Ingestão de nutrientes, armazenamento de nutrientes e oxidação de nutrientes
This is going to be a bit of technical/unapplied article, I’m going to try to keep it short and to the point and mainly it serves as a background for some topics I want to talk about in the near future (especially alcohol) so just be forewarned as you start on this. When people talk about diet, it’s common to divide the various nutrients that humans consume into two gross categories which are:
- Macronutrients: nutrients consumed in large amounts (’macro’ = large)
- Micronutrients: nutrients consumed in small mounts (’micro’ = small)
I’m also going to assume that you’re getting your nutrients through food and it’s going in through your mouth. Certainly nutrients can be given via infusion but this is usually done in a hospital setting (sometimes athletes will rehydrate and carb-load with IV fluids and glucose, mind you) and I’ll assume you’re not doing that.
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Digestive Efficiency and Your Poop
Clearly anything you eat has to go through the process of chewing, swallowing and into the stomach for digestion. There a bunch of stuff happens where the nutrients are broken down to one degree or another. And either they get absorbed (moving into special cells to be released into the bloodstream, or lymphatic system in the case of dietary fats) or not. If you’re particularly interested in the digestion processes of the different macronutrients, I’d refer you to the specific articles:
A Primer on Dietary Fats Part 1 for fat digestion.
A Primer on Dietary Carbohydrates Part 1 for carb digestion.
What are Good Sources of Protein-Digestibility for protein digestion.
Nutrients that aren’t absorbed in the stomach move further down the intestine where in some cases (for example, certain fibers), they are digested by special bacteria and re-enter the bloodstream as short-chain fatty acids. This is discussed in Fiber – It’s Nature’s Broom.
Nutrients that pass that stage eventually come out the other end in your poo and we needn’t talk about that much more. I’ll only note in this regards that digestive efficiency in humans is generally very high. Fats are absorbed with about 97% efficiency (e.g. if you eat 100 grams fat, you’ll absorb 97 grams of them), animal source proteins are about 90-95%, vegetable source proteins can be in the 80% range and carbohydrates vary drastically depending on their form, fiber content, etc. But for the most part, with the exception of high-fiber foods, you’re not losing a lot of calories in your poop.
I would note, having said more about poop than necessary at this point, that there appears to be slight differences (based on the gut bacteria present) in how efficiently individuals absorb calories from the diet but this only amounts to perhaps a 100 cal/day difference between the highest and lowest people. OF course, in cases of specific disease where there is nutrient malabsorption, all these comments go out the window but I won’t talk about that here. I’ll assume you have a normally functioning gut, etc.
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Fates of Ingested Nutrients: Oxidation or Storage
So what happens after nutrients get through the stomach and intestines and into the body? Broadly speaking, there are two primary fates for nutrients at this point which are oxidation or storage. A third that I should at least mention is that, under certain conditions, nutrients will sort of ’sit’ in the bloodstream either causing problems there or eventually being excreted in the urine. Outside of various pathophysiologies (e.g. runaway diabetes where glucose is lost in the urine in large amounts), the urine excretion route is generally minimal approaching insignificant and I won’t focus on it further here.
Oxidation simply refers to the direct burning of fuels for energy. This can occur in the liver, skeletal muscle and a few others places and all 4 macronutrients can strictly speaking undergo oxidation after ingestion. So fatty acids from dietary fat ingestion can be used to produce energy, carbohydrate can be burned off, a little appreciated fact is that under normal circumstances as much as half of all dietary protein ingested gets metabolized in the liver via a process called deamination with some of it simply being burned off for energy.
Storage should be fairly clear and the nutrients (with the exception of alcohol) can be ’stored’ in the body for later use. Carbohydrates can be stored as liver or muscle glycogen, under rare circumstances they are converted to and stored as fat. Dietary fat is stored either in fat cells or can be stored within muscle as intra-muscular triglyceride (IMTG). Under certain pathological conditions, fat gets stored in places it’s not supposed to go, a situation called ectopic fat storage. In a very real sense there’s no true store of dietary protein although amino acids from protein digestion are used to make various proteins and hormones in the body. Skeletal muscle is, in essence, a ’store’ of protein in the body. There is no store of alcohol in the body.
Which is the segue into the only real point I have to make in this piece: as it turns out, the size of a nutrient’s store in the body is inversely related to the body’s propensity to oxidize it after ingestion. This is especially true in terms of the size of the store relative to the amount consumed on a daily basis.
Put a little more clearly, the better the body’s ability to store a given nutrient, the less it tends to alter/increase oxidize that nutrient after ingestion. And vice versa, the smaller the store in the body of a given nutrient relative to intake levels, the more likely the body is to oxidize that nutrient after ingestion. I’ve shown the implications of this in the table below and will make comments about specific nutrients below that.
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| Nutrient | Size of store relative to daily intake | Oxidation increase due to intake |
| Fat | Very high | Low |
| Carbohydrate | Roughly equal | High |
| Protein | Moderate | Moderate |
| Alcohol | None | Perfect |
Fat
Body fat stores are effectively unlimited as individuals reaching 1000 lbs (and 70-80% body fat) have demonstrated. Even a relatively lean male at 180 lbs and 12% body fat is carrying 21 pounds of fat. Each pound contains maybe 400 grams of actual stored fat and that means about 8500 grams of fat stored in the body. Contrast this to a relatively high daily intake of perhaps 100-150 grams per day and you can see that the body’s store of fat is much much higher than what you eat on a day. And most people aren’t 12% body fat.
But for the most part, ingested dietary fat has little impact on fat burning in the body; that is, when you eat dietary fat, your body doesn’t increase fat oxidation. One exception is if an absolutely massive amount of fat (like 80 g) is consumed all at once but even then the effect is fairly mild. Some specific fats, notably medium chain triglycerides, are somewhat of an exception to this; they are oxidized in the liver directly. Rather, the primary controller of dietary fat oxidation in the body is how many carbohydrates you’re eating, which I’ll explain momentarily.
Carbohydrate
For carbohydrate, the body’s stores are relatively close to the daily intake. A normal non-carb loaded person may store 300-400 grams of muscle glycogen, another 50 or so of liver glyogen and 10 or so in the bloodstream as free glucose. So let’s say 350-450 grams of carbohydrate as a rough average. On a relatively normal diet of 2700 calories, if a person eats the ‘recommended’ 60% carbs, that’s 400 grams. So about the amount that’s stored in the body already.
For this reason, the body is extremely good at modulating carbohydrate oxidation to carbohydrate intake. Eat more carbs and you burn more carbs (you also store more glycogen); eat less carbs and you burn less carbs (and glycogen levels drop). This occurs for a variety of reasons including changing insulin levels (fructose, for example, since it doesn’t raise insulin, doesn’t increase carbohydrate oxidation) and simple substrate availability. And, as it turns out, fat oxidation is basically inversely related to carbohydrate oxidation.
So when you eat more carbs, you burn more carbs and burn less fat; eat less carbs and you burn less carbs and burn more fat. And don’t jump to the immediate conclusion that lowcarb diets are therefore superior for fat loss because lowcarb diets are also higher in fat intake (generally speaking). You’re burning more fat, but you’re also eating more. But that’s a topic that I’ve not only addressed previously on the site but may look at in more detail in a future article with this piece as background.
Protein
The body’s total protein stores (and note again that this isn’t a true store in the sense of body fat and glycogen) is maybe 10-15kg or so when you add it all up. Which is pretty high compared to an average daily intake. The DRI for protein is only about 50-60 grams per day for the average person and even folks eating 200-300 grams per day are still eating far less protein than stored. Which is why protein oxidation rates can change with intake.
As I mentioned above, an under-appreciated fact is that about half of all ingested dietary protein is metabolized in the liver (details on this can be found in The Protein Book). Some of it is oxidized for energy while others are converted into other things (including glucose and ketones) for use elsewhere. But, protein oxidation rates do change in response to intake. So, when protein intake goes up, oxidation will increase; when protein intake goes down, oxidation rates decrease. This change isn’t immediate (as it more or less is for carbohydrates) and takes 3-9 days to occur but mis-understanding of this process has led to some goofy ideas such as protein cycling.
But it also explains one other issue of importance to protein which has to do with speed of digestion. Early studies, including the oft-cited study on whey and casein by Boirie find that fast proteins are burned off for energy to a greater degree than slower digesting proteins. Since the body doesn’t have anywhere to store the rapidly incoming amino acids, it simply burns off more for energy. This, along with differences in handling (e.g. the fact that fast proteins are absorbed by the gut as discussed in Casein Hydrolysate and Anabolic Hormones and Growth – Research Review) are a big part of why slower digesting proteins invariably lead to better overall protein retention in the body; not only does more make it into the bloodstream but less is burned for fuel.
Alcohol
And, finally, as noted above, there is absolutely no store of alcohol in the body. None whatsoever. Effectively, alcohol is seen as a sort of metabolic ‘toxin’ or ‘poison’ to the body. And this means that alcohol oxidation is 100% perfect, that is, the body will effectively do everything in its power to get rid of the alcohol increasing alcohol oxidation to maximum (which means decreasing the oxidation of other nutrients consumed with that alcohol) so that the alcohol can be gotten rid of.
I’m going to ask readers not to read anything into the above paragraph, don’t infer or try to draw conclusions about how alcohol might or mightn’t fit into the diet in terms of anything. As it turns out, alcohol is an oddity among nutrients with seemingly contradictory effects on things. I’m going to address that in detail in a forthcoming article and, for now, just take the above as some much needed background information.
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Summing Up
And that’s that. After consumption and digestion, nutrients have a couple of primary fates in the body which are oxidation (burning) and storage (for use later). And, as it turns out, the propensity for the body to store or oxidize a given nutrient is related to the body’s built-in store relative to intake. In the case of dietary fat, where stored fat is much higher than daily intake, the body tends to store incoming fat and burn very little. Fat intake per se has very little impact on fat oxidation rates.
Rather, the rate of fat oxidation is related to carbohydrate intake as the body is able to precisely alter carbohdyrate oxidation to changing intake. Eat more carbs and burn more carbs (and less fat); eat less carbs and burn less carbs (and more fat). Protein is somewhere in the middle, oxidation can increase or decrease relative to intake but the effect takes time (3-9 days). Finally is alcohol, with no storehouse in the body, alcohol oxidation will take 100% precedence over everything else when it is consumed. I’ll discuss the implications of this in an article on alcohol (and it’s rather schizoid effects on body weight and body composition in a later article).
The Energy Balance Equation
Recently on the Internet, a common meme is that the application of thermodynamics to the human body is incorrect. This usually comes out of people talking about something that they clearly do not understand in any way shape or form which is the energy balance equation.This is usually used as a lead in to the idea that the “Calorie theory of weight gain and weight loss” is incorrect or what have you. This leads to even more abjectly stupid ideas that I’m not getting into here.
Today, I’m going to do my best to clear things up about what the energy balance equation does and doesn’t mean and why people, who don’t really have a clue what they’re talking about, don’t understand it. Hopefully by the time you’ve gotten to the end of this, you’ll understand it.
What is the Energy Balance Equation?
In its simplest form, the energy balance equation is meant to represent what does (or at least should) happen to the body by looking at the difference between energy intake (from food) and energy output.
In it’s exceedingly simplest form, the energy balance equation is this:
Energy in = Energy out + Change in Body Stores
This is essentially just a restatement of basic thermodynamics, since energy can’t be created or destroyed, it all has to be accounted for in some form or fashion. In this case, differences between intake and output show up as changes in the energy stores of the body.Now, in the case of the human body, changes in energy stores will show up as changes in the amount of different tissues in the body. Excess energy is converted or stored via conversion into body tissue (e.g. body fat, muscle tissue, etc.). Since excess energy is stored in the body as tissues that contain mass, I will (marginally incorrectly) refer to changes in body mass throughout this article.
I’m doing this as people tend to fixate on changes in mass/weight rather than on energy per se (we can measure changes in weight on the scale, or changes in fat or muscle mass; you can’t readily measure changes in energy stores of the body). As you’ll see below, this confusion about the energy value of different tissues is a big part of the confusion and claims regarding the equation itself.
By the same token, if energy intake is less than output, the body will pull on stored energy within the body and there will be some loss of tissue (e.g. fat, muscle, etc.). Again, I’ll refer to changes in mass in this article, just realize that, for technical accuracy, the real changes is in the energy store of the body.
Now, the above is a very simplified version of the energy balance equation and this is part of where folks get into problems.
But we have three basic bits of the equation: Energy In, Energy Out and Change in Body Stores. I want to look at each including some of the places that people make some really flawed arguments and draw some really flawed conclusions based on their misunderstanding of what’s going on.
A More Detailed Look at the Equation: Energy In
Now, energy in is actually the simplest aspect of all of this, this represents the number of calories that you ingest each day from the nutrients protein, carbs, fat, fiber and alcohol.
Of course, even that is not so simple. First and foremost, not all foods are digested with identical efficiency. On average, high quality animal-source proteins are digested with roughly 90-95% efficiency with vegetable source proteins coming in lower than that (80-85%), fats digest with about 97% efficiency and carbs can be as low as 80% depending on fiber content.
There can be some variance between different sources of the same nutrient as well. For example, a recently developed carbohydrate called resistant starch (it resists digestion) is absorbed with poor efficiency, more calories are lost in the stool compared to other carbs; some sugar alcohols share this effect (although they can just as readily cause massive stomach upset and diarrhea because of it). You don’t generally see massive differences in proteins or fats although there can be slight differences.
Put differently, some energy is lost prior to digestion (and shows up in the feces), never to be absorbed by the body. But strictly speaking you can make an adjustment on the energy in side of the equation to take digestibility into account with a correction factor (which would vary depending on the nutrient in question)
But I think you get the idea: the point is that the calorie in value can vary a bit depending on the specific nutrient and source of that nutrient. The amount of calories listed on the side of the food you’re eating may not be exactly the number of calories that make it through digestion and into the body. If anything, the value will be slightly less.
High-fiber diets tend to have this effect generally, as soluble fiber binds a small amount of protein and fat in the stomach carrying it out without digestion. So if you jack up soluble fiber intake, you end up absorbing less of the calories that went into your mouth; more are lost in your poop.
There is also some evidence that based on differences in the bacteria in the gut, there may be small differences in how well or poorly people extract energy from food during digestion, the most recent paper I’ve seen suggests that this can vary by roughly 100 calories per day. So that’s another place where the equation might be modified for any given individual.
I’d mention that, currently, no-one knows how to modify this in any useful fashion (although weight loss per se appears to cause the gut bacteria to shift to a different type) but that technology (through the use of pre- or pro-biotics) will likely come through in a few years.
Please note: This doesn’t deny the validity of the energy balance equation, it just means that it’s more complicated than people realize.
A More Detailed Look at the Equation: Energy Out
The energy out part of the equation is more complicated than people understand and I’d recommend my article Metabolic Rate Overview for a detailed look at the different components of the out part of the equation and their determinants.
Summing up, there are 4 primary aspects of the energy out part of the equation which are Resting/Basal Metabolic Rate (RMR/BMR), the Thermic effect of food (TEF), the Thermic Effect of Activity (TEA) and a more recent addition which is Spontaneous Physical Activity/Non-Exercise Activity Thermogenesis (SPA/NEAT). Essentially TEA refers to calories burned through formal exercise/activity, SPA/NEAT is more subconscious and represents daily movement, going from seated to standing, fidgeting and a host of other stuff that isn’t conscious voluntary exercise.
I’m going to come back to this below but something that is VERY important to remember is that none of the above is static: it all changes based on what the person is doing and their diet, activity, environment, etc.
A Mid-Article Review
So I’ve looked at some of the factors that can modify both the energy in and energy out part of the equation. Now we can rewrite the equation a bit more usefully as:
Energy In (corrected for digestion) = (BMR/RMR + TEF + TEA + SPA/NEAT) + Change in Body Stores
Even that’s not complete and there are other things that can go on the energy out side of it, various inefficiencies in biochemical pathways (that basically waste calories through heat) and such things. I’d note that most of these don’t appear to contribute terribly significantly to the energy out side of things but they are worth noting since they modify the overall equation.I’d also note that people often make comments about the above equation which shows just how utterly clueless they are about it. For example, people will point out that replacing carbs with protein leads to greater weight loss although they have the same calories; ergo the equation is wrong. What they fail to realize is that protein has a higher thermogenic effect and this modifies the TEF value of the equation; the energy OUT side of the equation changes if you replace carbs with protein. But they seem to try to treat the sides of the equation independently in this case; which is wrong.
Now, even with the above, a commonly made argument that the energy balance equation is wrong is that, invariably, changes in either intake or expenditure don’t seem to scale with predicted or expected changes in body mass. That is, armed with the above, if you know intake and output, you should be able to know exactly how much body mass will change, right?
Put differently, it’s commonly stated that if you reduce food intake by 500 calories/day you will lose one pound per week. Yet when people do that very thing, this never happens in the real world. Or if you add 500 calories/day of food, you should gain a pound, and that pretty much never happens either in the real world.
Hence the equation is invalid, right? Wrong.
There are three different reasons why the expectations of most people in terms of changes in the energy balance are incorrect and, again, it’s based on their own simplistic understanding of what’s going on. Those three reasons are
- Water balance
- Muscle and fat are not identical
- The fact that the energy balance equation is not static
Water Balance
This is the easiest to explain so I’ll tackle it first. First note that water contains zero energy and zero calories. I can add a billion gallons of water to either side of the equation and it doesn’t affect the equation itself (quick note: some work suggested that ingestion of water, or cold water, could increase energy expenditure so that is an indirect way that water might impact on the equation, but this is not what I’m talking about).
However, water balance issues completely screw up expectations about changes in body mass. Every woman reading this knows that she can swing some amount of body weight (could be a couple pounds, could be 10 pounds) across a menstrual cycle and carbohydrate intake has a massive impact on water balance. But those changes don’t mean anything in terms of the energy balance equation.
Early studies of very-low carb diets (all discussed in detail in my first book The Ketogenic Diet) reported water loss ranging from like 1-15 pounds in the first few days. I’m fairly little and I can drop 7 lbs of water in 3 days of carbohydrate restriction (it comes right back with carb-loading).
Similarly, if you add a bunch of sodium to someone’s diet after a period of low-sodium intake, they will gain several pounds of water. But it doesn’t affect the energy balance equation in any way because water has no caloric/energy value.
I’ve talked about this on the site in various contexts, in the article Of Whooshes and Squishy Fat, I talk about how water retention can mask true fat loss in some people. The deficit is there, the activity is there and nothing is happening. Then boom, overnight, 5 pounds drops off. It’s not a thermodynamic miracle, nor does it defy the energy balance equation, water shifts just screw things up.
I discussed this in a different context in the article Not Losing Fat at a 20% Deficit, What Should I Do?, some people seem prone to retaining water (they tend to be a little bit ‘tightly wound’ mentally in my experience), they overproduce cortisol (which shows cross-reactivity with the mineralocorticoid receptor) and this causes water retention, especially when they diet and train too hard. They maintain a nice deficit, etc. but nothing is happening. Energy balance equation is wrong, right? Nope, it’s just water.
The same thing works in the other direction, early studies (invariably lasting 4-7 days) on very low carb diets found greater WEIGHT loss for the lowcarb vs. high-carb diets. Aha, there’s a metabolic advantage. Nope, it’s just water loss (due to a variety of mechanisms) and water doesn’t have calories on either end of the equation. So this doesn’t disprove the energy balance equation because water has no calories.
So that’s reason one while the expected change in body mass often doesn’t scale with the deficit or expectations: water loss throws everything off. This doesn’t invalidate the energy balance equation though, because water doesn’t have energy on either side.
Muscle and Fat are Not Identical
The next wrench that throws people into confusion about the energy balance equation has to do with the difference in gaining or losing fat and muscle. We’ve all heard for decades that if you create a 3,500 cal/week deficit, you will lose one pound and this is what people expect to happen exactly without fail, and if it doesn’t, clearly the energy balance equation is invalid.
Did you ever wonder where that value of 3,500 cal per pound comes from?
Quoting from The Stubborn Fat Solution:
WAT in humans is composed primarily (anywhere from 80 to 95%) of lipid. By lipid, I
mean stored triglycerides (TG) which are simply a glycerol molecule bound to three free
fatty acid (FFA) chains. The remaining part of the fat cell is comprised of a little bit of
water as well as all of the cellular machinery needed to produce the various enzymes,
proteins, and products that fat cells need to do their duty. As it’s turning out, fat cells
produce quite a bit of stuff, some good, some bad, that affects your overall metabolism.
For the record, one pound of fat is 454 grams and let’s assume 90% lipid on average. So
about 400 or so grams are actual stored TG. When burned by the body, one gram of fat
provides 9 calories so 400 grams of fat contains about 3600 calories of stored energy. Now
you know where the old axiom of ~3,500 calories to lose a pound of fat comes from.
Note: WAT = white adipose tissue, the primary type of fat in the human body.
So there ya’ go, create a 3,500 cal/week deficit and you should lose one pound of fat, right? Again, wrong.There is a built in assumption in the above that turns out to not be necessarily correct but also throws a wrench into expectations about the energy balance equation. That assumption is that 100% fat is being lost when a deficit is created. Now, if you diet correctly (e.g. the way I describe in my books), this is a pretty good assumption but it’s not universally true. Often people also lose muscle and connective tissue on a diet.
And the issue is that muscle and connective tissue doesn’t provide as much energy to the body as a pound of fat. Rather than 3,500 calories to break down a pound of fat, a pound of muscle provides about 600 calories to the body when it’s broken down for energy.
Let me put this in mathematical terms, to show you how the identical 3,500 calorie/day deficit can yield drastically different changes in body mass depending on what percentage of tissue you’re losing. I’m going to use the extremes of 100% fat, 50/50 fat and muscle, and 100% muscle.
| Condition | Energy Yield | Total Weight Lost |
| 100% Fat | 3500 cal/lb | 1 pound |
| 50%Fat/50% Muscle | 2050 cal/lb | 1.7 pounds |
| 100% Muscle | 600 cal/lb | 5.8 pounds |
See what’s going on? The assumption of one pound per week (3,500 cal/week deficit) is only valid for the condition where you lose 100% fat. If you lose 50% fat and 50% muscle, you will lose 1.7 pounds in a week for the same 3,500 calorie deficit. Lose 100% muscle (this never happens, mind you, it’s just for illustration) and you lose 5.8 pounds per week.
I’d note that I suspect this is why many rapid weight loss centers advise against exercise: exercise limits muscle loss on a diet and the simple fact is that you will lose MORE TOTAL WEIGHT faster if you lose muscle.
Finally, I’d note that most obesity researchers assume a loss for obese individuals of roughly 25% lean body mass and 75% fat which would put the true expected weight loss somewhere between the 1 lb/week and 1.7 pounds per week. But I don’t feel like doing the math.
I should note that the above numbers aren’t the same as for weight gain but there are differences in the amount of energy required to store one pound of muscle vs. one pound of fat. So there are still differences and this means that the predicted weight gain and actual weigh gain won’t be identical; the math just isn’t quite the same as what I presented above.
But the critics say, it still never works out that way. Even if you account for water and the above, the math still never works out. The calorie hypothesis is still incorrect.
But they always seem to steadfastly ignore the final factor.
The Energy Balance Equation Isn’t Static
This is the real biggie which is why I saved it for last. As noted above, the energy balance equation can be written a bit more complexly as:
Energy In (corrected for digestion) = (BMR/RMR + TEF + TEA + SPA/NEAT) + Change in Body Stores
Here’s what I want to talk about now: every factor on the right hand side, BMR/RMR, TEF, TEA and SPA/NEAT can change based on environment. Please read that sentence again a couple of times.People have this weird tendency to assume that if their maintenance caloric intake is exactly 2500 calories (at calorie balance); therefore if they start eating 2000 calories (or increase activity to burn 500 calories/day) they should lose exactly 1 pound of fat per week. Or that that 2,500 calorie/day maintenance will not change.
Ignoring the water balance and muscle vs. fat thing, this is still incorrect and here’s why: the equation isn’t static. It changes. Sometimes considerably. And this makes predicted and actual changes in body mass different.
Some examples:
When you lose weight, BMR/RMR goes down. Some of this is simply due to reduced body weight (a smaller body burns less calories) but there is also an adaptive component due to changes in hormones like leptin, insulin, nervous system output and thyroid hormones (this topic is discussed in detail in both The Rapid Fat Loss Handbook and A Guide to Flexible Dieting). This lessens the actual deficit that is being created because the previously estimated maintenance value is no longer correct (to keep losing fat at anywhere near the same rate, calories have to be reduced further to take this reduction into account).
The Thermic effect of food is related directly to the amount of food that you’re eating. Now, TEF is usually rough-estimated at 10% of total food intake (this is just an average value for average diets). But that means that if you reduce food intake by 500 cal/day, you will be burning 50 cal/day less via TEF. Your previous maintenance of 2500 has already been reduced to 2450 cal/day. So the assumption of a static 2500 cal/day maintenance is already made invalid simply by the act of reducing food intake (albeit slightly).
Ok, you say, what if I add exercise instead? Well, some research has found that (and this usually happens in older people) excessive amounts of activity burned during exercise causes people to move around less later in the day. For example, say you put yourself through 500 calories of hard activity but, due to fatigue, you sit on the couch more later that night, burning 300 calories less than you expended before training. The supposed 500 calorie deficit you’re creating is really only 200 calories because your SPA/NEAT has adjusted itself. You might expect one pound per week fat loss but the deficit is actually less than half of that (200 cal/day * 7 days = 1,400 calories = 0.4 pounds fat per week).
As well, people often get lethargic on a diet, they move around less. The 2500 cal/day maintenance level goes down because SPA/NEAT goes down because they have less energy. The amount of daily movement that occurred at caloric balance (or surplus) drops. So the expected deficit (and hence change in body mass) is no longer accurate since parts of the energy out equation have changed.
I’d note that all of this goes for weight gain and overeating as well. All of the components can change, sometimes considerably. So the predicted or expected weight gain in response to a given change in energy intake is rarely exactly what is seen. That’s in addition to water balance issues and the difference in caloric value of muscle and fat.
BMR/RMR goes up a bit when people overeat, of course gaining weight raises RMR/BMR because a larger body burns more calories. Since TEF is directly related to energy intake, if you increase food intake, TEF goes up slightly (and this depends on the nutrient in question with protein having the largest effect).
Changes in SPA/NEAT can vary hugely and explain most of the discrepancies in expected vs. actual weight gain. In the earliest study, when overfed nearly 1000 calories/day weight/fat gain varied almost 10 fold but this was explained by massive variance in NEAT; some people increased their spontaneous movement by 700 cal/day (making the true surplus 300 cal/day) while one poor person (a woman) had her NEAT go down a little bit (she gained the most fat). This is mostly genetic, unfortunately.The point of all of this is this: When people say that the energy balance equation is invalid, this is simply not the case. The equation is completely valid, what is invalid are the assumptions that people are making about what the equation means or says.
I think when you read articles decrying the energy balance equation as invalid or incorrect, you’ll find that they ignore (or simply are unaware) of all of the above. The equation is perfectly valid and humans are as subject to the laws of thermodynamics as anything else in the universe. Physics is not just a good idea, kids, it’s the law.
Most claims that the energy balance equation is invalid are due to people simply not knowing what they are talking about. The equation is valid, it has to be, what’s invalid are people’s assumptions about how things should work.
Final note, I’m turning off comments on this article for reasons I think people will find obvious.
On that note, don’t try to sneak in comments (good or bad) in the comments section of other articles, they will be deleted. And that goes for both positive AND negative comments. I just deleted one positive comment because it would be intellectually dishonest of me to allow positive ones to get through and delete negative ones. None of them are getting through on this piece.
Also, if you want a quick review on the topic, I’d suggest the following paper:
Schoeller DA. The energy balance equation: looking back and looking forward are two very different views. Nutr Rev. 2009 May;67(5):249-54.
How We Get Fat
Ok, this is going to be a bit ranty but, trust me, I write better when I’m upset. If the Internet has proven anything to me over the years it’s this: basic literacy is sorely lacking. Because the comments in response to the article I wrote on Tuesday, Excess Protein and Fat Storage – Q&A indicate that not only can people not understand rather basic concepts, they insist on reading things into what I am saying that I have never said. I could rant about making uncritical inferences but I’ll spare everyone that.In that piece I answered a very specific question with a very specific answer. I made no implications of anything beyond the exact answer I gave to that specific question. And somehow people managed to read all kinds of asinine stuff into it, things that I never said or even began to imply. It’d amaze me if I hadn’t seen people do this consistently over the past 15 years.
The basic confusion in that article was that folks interpreted my saying that carbs and protein can’t be converted to fat as ‘Lyle says you can’t get fat overeating carbs and protein’. Which I absolutely didn’t say. But people inferred, incorrectly. Basically, what I said and what they heard were not the same thing.
I’d note before continuing that if folks had taken 30 seconds to click on and read the article I linked Nutrient Intake, Oxidation and Storage, they would have realized the mistake they were making as I specifically said that overeating carbs can still make you fat, just not through direct conversion (rather through indirect mechanisms). But in addition to a lack of basic literacy, laziness seems to be endemic on the net as well. And for not taking a couple of minutes to read the piece that I specifically linked to, a bunch of people got confused and then aggro.
I’d also note that if folks reading the protein piece had taken time to read the, I dunno, 200+ other articles on the site, they’d realize that I am making no such claim that you can eat all the carbs you want (or that lowcarb diets are superior, or whatever nonsensical conclusions they reached). Or that one specific dietary approach (e.g. lowcarbs) is automatically superior to another.
But rather than do that, they took a single article, addressing a single specific question, and ran with it. That’s not a good thing to do, you can’t take a single answer to a single specific question out of context and take that to represent what I believe. Well you can but it’s stupid to do so. That’s what a lot of people did.
But since they couldn’t do any of that, couldn’t take the time to even read the single linked article much less the rest of what’s on the site, rather than writing about something more interesting today, I’m going to clear it up once and for all. And I still expect someone to read this completely wrong and go around the Internet mis-representing what I’m saying. I’m used to it at this point.
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How We Get Fat Part 1: Energy Intake Exceeds Energy Output
At a fundamental level, fat storage occurs when caloric intake exceeds caloric output, a topic I discussed in some detail in The Energy Balance Equation. Now, I know that a lot of people claim that basic thermodynamics don’t hold for humans. Simply, they are wrong. Invariably, the studies used to support this position are based on a faulty data set: to whit, they are drawing poor conclusions about what people SAY that they are eating.
For example, one popular book bases one of its many incorrect theses on a 1980 report suggesting that the obese ate the same number of calories as the lean. Ergo, obesity was caused by something else. The problem is this, the data set is wrong. A fact we’ve known for nearly 30 years but that the author was somehow unable to become aware of in his ‘5 years of dedicated research’.
Study after study after study over the past 30 years shows that the obese systematically under-report their food intake (by up to 30-50%) and over-report their activity (by about the same). So when they say they are only eating 1800 calories per day, they may be eating 2400-3600 calories per day. And their activity isn’t nearly what they think.
And when you put those same folks in controlled metabolic ward conditions and control their food intake and/or activity output…voila, the energy balance equation holds. It’s only when you believe the (incorrect) self-reported data that it doesn’t.
And make no mistake I am NOT saying that the obese are lying about their intake, not consciously anyhow. Most people simply suck at knowing how much they are actually eating. Leave them to self-report it and they almost always screw it up. If you’re mistaken enough to believe the self-reported values, you reach even more screwed up conclusions about things.
In that vein, I have found that the chronically underweight “I can’t gain weight no matter what I do” are invariably vastly over-estimating what they are eating. That is, they are eating far less than they think. Other studies show that ‘health conscious people’ tend to under-report their true ‘junk food’ and dietary fat intake; to appear more healthy they conveniently forget or leave out that trip to the burger joint.
Put differently, this isn’t something that only occurs in the obese (so spare me accusations of ‘hating the obese’ or some nonsense). Am I clear or are people going to misinterpret me some more in the comments and claim I said that fat people lie about their food intake? Because I’m not saying anything of the sort. Make no mistake, I’m sure some do lie about it; most are just clueless about how much they are actually eating.
Now let me make it clear that there is obviously a lot more going on here, hormones and all manners of other stuff impact on the energy balance equation. For example, chronically elevated cortisol does a lot of nasty things in terms of reducing metabolic rate (reducing the energy out side of the equation) as well as negatively impacting on calorie partitioning (where calories go when you eat them as discussed in Calorie Partitioning Part 1 and Part 2). But for the most part, a lot of that is outside of our control. It’s relevant but you can’t do much with most of it. So I’ll focus on calories.
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How We Get Fat Part 2: Nutrient Intake, Oxidation and Storage Part Deux
The primary storage of fat in the body is in fat cells, duh. Most of that is found in what is called subcutaneous fat, which is found under the skin. There is also fat stored around the gut area called visceral fat (this surrounds the organs). Fat can also be stored in ‘bad’ places like the liver and pancreas under certain conditions; this is called ectopic fat storage.
I’m going to focus here on subcutaneous fat. There, whether or not fat is stored or removed comes down to a concept called fat balance, which I discuss in some detail in The Ultimate Diet 2.0. You can think of fat balance as the fat specific equivalent of energy balance. That is
Net Change in Fat Stores = Fat Stored – Fat Burned
I’d note that the same nutrient balance holds for protein, carbohydrates and alcohol (which I’m not going to talk about today). That is, the net effect on bodily stores, whether protein or carbohydrate stores in the body increases, decreases or stays the same comes down to the balance of protein/carb stored vs. protein or carbs/burned.
So at a fundamental level, fat gain occurs when fat storage exceeds fat burning (technically oxidation). And fat loss occurs when fat oxidation exceeds fat storage. I’d note that both processes take place in some amounts throughout the day, controlled by a host of processes I’m not going to talk about. Just recognize that what happens over time in terms of your fat stores comes down to the relationship between those two processes: fat storage – fat oxidation.
So what determines fat oxidation and fat storage rates?
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How We Get Fat Part 3: Back to Nutrient Intake, Oxidation and Storage
Now, here’s where people got confused by Excess Protein Intake and Fat Storage – Q&A, and where they would have been unconfused by clicking the linked article on Nutrient Intake, Oxidation and Storage. In fact, I’d suggest you go read it right now, it’s not that long and since I’m not going to retype all of it here (that’s why I wrote it the first time), it’d be a good idea. I’ll wait.
However, since I know most of you will have just ignored my suggestion to actually read that piece, I’m going to summarize a few points from it (as well as from the Q&A):
- Carbs are rarely converted to fat and stored as such
- When you eat more carbs you burn more carbs and less fat; eat less carbs and you burn less carbs and more fat
- Protein is basically never going to be converted to fat and stored as such
- When you eat more protein, you burn more protein (and by extension, less carbs and less fat); eat less protein and you burn less protein (and by extension, more carbs and more fat)
- Ingested dietary fat is primarily stored, eating more of it doesn’t impact on fat oxidation to a significant degree
Carbohydrates are rarely converted to fat (a process called de novo lipogenesis) under normal dietary conditions. There are exceptions when this occurs. One is with massive chronic overfeeding of carbs. I’m talking 700-900 grams of carbs per day for multiple days. Under those conditions, carbs max out glycogen stores, are in excess of total daily energy requirements and you see the conversion of carbohydrate to fat for storage. But this is not a normal dietary situation for most people.
A few very stupid studies have shown that glucose INFUSION at levels of 1.5 total daily energy expenditure can cause DNL to occur but this is equally non-physiological. There is also some evidence that DNL may be increased in individuals with hyperinsulinemia (often secondary to obesity). There’s one final exception that I’ll use to finish this piece.
But when you eat more carbs, you burn more carbs and burn less fat. And that’s why even if carbs aren’t directly converted to fat and stored as such, excess carbs can STILL MAKE YOU FAT. Basically, by inhibiting fat oxidation, excess carbs cause you to store all the fat you’re eating without burning any of it off. Did you get that? Let me repeat it again.
Carbs don’t make you fat via direct conversion and storage to fat; but excess carbs can still make you fat by blunting out the normal daily fat oxidation so that all of the fat you’re eating is stored. Which is why a 500 cal surplus of fat and a 500 cal surplus of carbs can both make you fat; they just do it for different reasons through different mechanisms. The 500 calories of excess fat is simply stored; the excess 500 calories of carbs ensure that all the fat you’re eating is stored because carb oxidation goes up and fat oxidation goes down. Got it? If not, re-read this paragraph until it sinks in.
Oh yeah, the same holds for protein. Protein isn’t going to be converted to and stored as fat. But eat excess protein and the body will burn more protein for energy (and less carbs and fat). Which means that the other nutrients have to get stored. Which means that excess protein can still make you fat, just not by direct conversion. Rather, it does it by ensuring that the fat you’re eating gets stored.
Of course protein also has the highest thermic effect, more of the incoming calories are burned off. So excess protein tends to have the least odds of making you fat under any conditions; but excess protein can make you fat. Just not by direct conversion to fat; rather it’s indirectly by decreasing the oxidation of other nutrients.
Ok, is the above clear enough? Because I can’t really explain it any simpler but will try one last time using bullet points and an example. Let’s assume someone is eating at exactly maintenance calories. Neither gaining nor losing fat. Here’s what happens with excess calories. Assume that all three conditions represent identical increases in caloric intake, just from each of the different macros. Here’s what happens mechanistically and why all three still make you fat:
- Excess dietary fat is directly stored as fat
- Excess dietary carbs increases carb oxidation, impairing fat oxidation; more of your daily fat intake is stored as fat
- Excess dietary protein increases protein oxidation, impairing fat oxidation; more of your daily fat intake is stored as fat
And I’d note again, since someone will invariably misread this that that doesn’t mean that a low-carb and/or low-protein diet is therefore superior for fat loss. I’m not saying that and don’t think that I am. Because in such a situation, while you may be burning more fat, you’re also eating more dietary fat. So net fat balance can be unchanged despite the dicking around with macronutrient content. It still comes down to the deficit.
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The Obvious Question: Why Not Just Eat Zero Dietary Fat?
And now I’ll answer the question that I know every person who has read (and hopefully understood) the above is asking: so if carbs and protein are rarely converted to and stored as fat, and make you fat by decreasing fat oxidation and causing all ingested dietary fat to get stored as fat, can’t I eat as much as I want of protein and carbs so long as my dietary fat intake is zero?
And the asnswer is still no. Remember how I teased you above with one other exception, when carbs are converted to fat for storage? That exception is when dietary fat is below about 10% of total daily calories. Under that condition, the body ramps up de novo lipogenesis. So you still get fat.
Because the body is usually smarter than we are. Under conditions where dietary fat intake is ‘adequate’ (meaning 10% of total calories or more), the primary fate of that fat is storage and protein and carbs are used for other things. And when dietary fat is too low, the body will start converting ingested carbs (and probably protein, though it would still be rare) to fat for storage.
Oh yeah, the other question you’re going to ask in the comments “What about alcohol?” That’s going to require a full article so be patient. I know that’s another thing lacking on the Internet but so be it.
And I really hope that clears things up. If it doesn’t, read this piece and the linked articles until it is.
Adjusting the Diet
In various places on the site, I have made the comment that such things as caloric intake and activity will have to be adjusted based on real-world fat loss. For example, in the Q&A on How to Estimate Maintenance Caloric Intake, I pointed out that one of the reasons that I use the quick estimates for such things as maintenance calories and setting initial caloric intakes is that they always have to be adjusted anyhow.Today I want to talk about how I do that adjustment, note that if you’ve read either The Rapid Fat Loss Handbook or A Guide to Flexible Dieting, this is the same information in the last chapter where I talk about setting up moderate deficit diets and how to adjust them. I’d only note that the same basic information can be used when either small or larger deficit are used as discussed in Setting the Deficit-Small, Medium or Large.
.A Quick Note about Water Balance
Before I get into the meat of the article, there is one topic I want to bring up first. Many people have an expectation of fat loss being this nice weekly linear thing that occurs in a predictable fashion. And certainly, for some people this can be the case. However, for an equally large number of people (and I’d probably tend to argue that these folks are in the majority), fat loss does not occur in a predictable linear fashion.
Rather, there are often stops and starts or, as it’s often referred to on the Internets, stalls and whooshes. I discussed this topic in some seriousness in The Stubborn Fat Solution and excerpted that bit in the article Of Whooshes and Squishy Fat. The main culprit here is almost always water retention which can mask fat true fat loss and make it look as if a diet that is otherwise set up perfectly (and working just fine) actually isn’t.
People vary in how predisposed they are to this occurring. Some folks seem to retain water like crazy, especially if they try to combine hard deficits with excessive and or too intensive of activity. Women of course have an additional factor of shifts in water balance throughout the menstrual cycle. Even that is massively variable, some women gain little to no water weight throughout the month, others can hold an extra 5-10 pounds (2.5-5kg or so) easily.
Coupled with a generally slower rate of fat loss in the first place, women can go nuts trying to figure out if their diet is working or not. Put differently, let’s say a woman is on a moderate deficit diet and should be losing right around 1 pound of fat per week. If she is holding an extra 5-10 pounds of water, it could take 5-10 weeks before she actually sees that her diet is working.
Of course, if the water retention is related to menstrual cycle stuff, what she should see if times of the month when her weight/fat is down (below where she started) and other times when it’s not. Plotting weight or some attempt to measure body composition on a monthly basis to see what the overall trend is is probably going to be more beneficial than looking at it on a week to week basis.
My point in bringing this up is actually not just to depress people. Rather, I’m pointing out that what I’m going to discuss in this article in terms of adjusting the diet can be done too often. For folks who have issues with water retention (who may see big drops every couple of weeks rather than smaller drops weekly), trying to gauge true weekly fat loss and adjust the diet is usually a losing proposition.
Rather, those folks may have to only look at what’s happening every 2 weeks to decide when and if to adjust their diet. Women with major menstrual cycle swings may even have to chart their monthly trends to see what’s happening and only make adjustments every 4 weeks.
Yes, I know this is a pain but at this point there’s really no solution for it. All of the methods that we have to measure body composition are too inaccurate to get around this and the point I want everybody to really take home is that expecting predictable weekly fat loss may not be realistic depending on individual propensity to hold water or not.
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Back to the Point
Accepting the above, that water balance can throw off expectations on a week to week (or even month to month) basis in terms of fat loss, the first necessary data point is what the predicted or expected fat loss actually is. I gave some examples of this in Setting the Deficit-Small, Medium or Large and clearly the expected fat loss will depend on two things: the size of the dieter and the size of the deficit. Bigger dieters and/or bigger deficits mean faster expected fat loss and vice versa.
For the purpose of this article, I’m going to use a relatively ‘average sized’ dieter and a moderate deficit with a weekly expectation of approximately 1-1.5 pounds per week of true fat loss. This would be a reasonable degree of fat loss for a relatively ‘average sized’ male using a moderate deficit (20-25% below maintenance); again the numbers would be different for smaller/larger dieters and/or smaller/larger deficits.
Based on that, the chart below is how I’d adjust calories (either by reducing food intake or increasing activity, again a topic I’ll address another day in terms of which may be better or worse) based on measured weekly (or bi-weekly) fat loss.
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| Average Weekly Fat Loss | Is There Performance Loss | Adjustment |
| Less than 1 lb/week | Reduce Calories by 10% | |
| 1-1.5 lbs/week | No Change | |
| 2+ lbs/week | No | |
| Yes | Increase Calories by 10% |
Frankly, there’s nothing that exciting in the chart and it should be fairly self-explanatory. If your predicted fat loss is 1-1.5 lbs/week (and you’re not messing up your calories somehow, through mis-measurement or what have you) and you’re not achieving that, you need to reduce calories further (or increase activity to burn the extra).
Clearly, if you’re hitting your goal numbers right on the spot, don’t change anything.
Of course, there are times when the actual weekly weight loss ends up being larger than expected. Some of this can be water or what have you but not always. And that leads me to an explanation of the middle column.
As I discussed in Weight Training for Fat Loss, one of the primary metrics that should be used while dieting (for non-athletes) is the maintenance of poundages in the gym. Now, it’s not always possible to maintain 100% of strength (and this tends to be a bigger issue as folks get to lower and lower body fat levels) but if major dropoffs are being seen and training is correct, that usually indicates that muscle is being lost. In that situation, the deficit must be reduced, either food intake should be increased or some of the extra activity (usually excessive cardio) should be reduced.
Of course, the same would go for athletes who are trying to reduce body fat levels, if some useful metric of their performance (e.g. run time, cycling power output, whatever) is worsening, then the deficit is too aggressive and calories should be increased (with any ‘junk’ or extra activity being reduced if necessary).
I’d note that, strictly speaking, I could have included the performance loss column for any of the weekly fat losses. Some people even doing everything ‘right’ simply can’t achieve optimal fat loss results without performance loss. They will need to use less agressive deficits (again either reducing food intake or increasing activity) to avoid major performance falloffs.
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Summing Up
And that’s how I adjust diets. Honestly, there’s nothing too majorly complicated to it and there are basically three steps.
First off you need to have some idea of what the expected or possible fat loss for a given deficit is. I’d note that people always want fat loss to be faster than it is no matter what they do. If they are losing 1 pound per week, they want 2 pounds per week. If they are losing 2 pounds per week, they want 4 pounds per week. If they are losing 5 pounds per week, they will want 10 pounds per week. This is just human nature but it’s not always realistic.
Certainly there are ways to do this (usually involving monster daily deficits as discussed in Setting the Deficit-Small, Medium or Large) but even there there is going to be some expected degree of fat loss based on the deficit that is created. You need to know what is realistic based on the deficit that is being created.
Second there needs to be some awareness of the issues related to whooshes, stalls and water balance. This basically relates to how frequently you are going to decide whether your current activity level and deficit need to be examined and/or adjusted in the first place. Folks vary in how much of an effect this has.
Women, on average, have bigger issues but some men also deal with it. If you know that you take 2 weeks before you see a drop, clearly using a single week of measurement to make a decision is a mistake. If you’re a woman with major monthly swings, you may have to only examine true fat loss on a 4 week cycle, using what happens weekly (or daily as is sometimes the case) will not only drive you nuts but be inaccurate.
And then you simply compare the expected fat loss to the actual fat loss. If what happened is less than what’s predicted (and you’re not mis-measuring food or something), then you need to increase the deficit slightly. If you’re right in the sweet spot, losing what you’d predict, don’t change anything. And if you’re losing more than predicted, you may need to increase calories (or decrease activity).
I usually use small adjustements here, 10% is usually fine for increases or decreases. Then stay there for whatever time period is appropriate for you individually and adjust again. Eventually you’ll nail it down to exactly where you need to be.
Since I imagine someone will ask about this in the comments, I’d note that, as people lose weight/fat, and maintenance requirements fall (both as a function of body mass loss along with the adaptive adjustments), often caloric intake has to be reduced further (or activity increased) to maintain the same degree of weight/fat loss. This is something I’ll address in more detail in a later article.
Finally, another consideration is performance loss. If you’re a general weight trainer or physique athlete, poundages in the gym are the usual metric. If they are cratering you are probably losing muscle; regardless of the weekly fat loss, you need to reduce the size of the deficit. You need to either increase calories or reduce volume (usually cardio). For performance athletes, there should be some performance metric that you’re tracking to judge if your diet is doing more harm than good. If that metric is going down, you need to reduce the size of the deficit.
Not Losing Fat at 20% Deficit, What Should I do? – Q&A
Question: If someone is looking to reduce body fat and is not showing progress at 20% below their calorie maintenance level, what would be the next logical step to induce fat loss? This person engages in regular aerobic and resistance training.Answer: The first question I would ask this person is if they had just started their diet and exercise program. I have often see this sort of weird ‘delay’ in fat loss when people first start a new diet/exercise program. And this tends to be far more so the case for women than for men (men always have it easier).
Trainees would be doing everything ‘right’ and absolutely nothing measurable would happen for the first four weeks. And then sometime after week 4, there will be this big change in body composition, seemingly overnight. On the Internet, this is often called the ‘whoosh’ (which usually comes after a ’stall’).
Which, of course raises the question of what is causing this to occur. Some of it may have to do with gene expression in terms of mobilizing and burning fat off the body, these pathways seem to take some time to get up to full speed when people are just starting out. Some of it may simply be the error in terms of making caliper measurements and our ability to measure small changes with current technology. I suspect a lot of it has to do with water balance. When in doubt, I just chalk it up to voodoo magic and acknowledge that it happens even if we don’t exactly know why.
I honestly suspect that weirdness in water balance plays a huge role in this; and there is a lot of individual variance in how much people are prone to retain water (simply, some are more prone than others). I discussed the ‘whoosh’ phenomenon in The Stubborn Fat Solution and honestly think that water retention and such tend to ‘mask’ true fat loss in a lot of cases, at least over the short term. Then seemingly overnight, it looks like someone has lost several pounds of fat; people wake up leaner and lighter. At some point in the future, I’ll write a full article about the topic.
And while the above applies to both men and women fairly equally, women have an additional issue which is the changes in water balance throughout the month due to the menstrual cycle. As I discussed in Body Composition Recommendations, some women can shift fairly significant amounts of water over the duration of their monthly cycle. That will tend to overwhelm all but the most extreme rates of fat loss.
Trying to measure fat or weight loss in women on a week to week basis is often a futile endeavor and females may have to measure only once per month (ideally at the same point in the cycle) to get any sort of consistent or comparative measures. Women should generally pick a specific point in their cycle and make all measurements then to track changes month to month.
Another option is to measure weekly but only compare the same week of the cycle each month. So week 1 of the cycle would be compared to week 1 of the cycle a month down the road, week 2 is compared to week 2, you get the idea. What doesn’t work is comparing week 1 to week 3 because the body may be holding a ton of water during one of the weeks and not during the other making comparison impossible.
Tangentially, an idea that seems to come in and out of fashion in bodybuilding circles is that of a water load. Bodybuilders who think that they are holding water may bump up water intake fairly significantly for a few days before cutting it back to normal levels. This can often help the body to normalize water balance and may help get past the water retention issue.
I’ve often also seen refeeds (high-carbohydrate overfeeding as discussed in A Guide to Flexible Dieting) trigger whooshes. A bit more accurately, people get fed up with dieting for a month with no visible results, say ’screw this’ and go pig out. And frequently wake up several pounds lighter and looking leaner. I just try to structure and control it a a bit better with structured refeeds.
Something else to consider has to do with the issue of the estimation equations for maintenance intake. As I discussed in How to Estimate Maintenance Caloric Intake, I use a rough estimate for maintenance of 14-16 cal/lb (31-35 cal/kg). A standard moderate deficit is usually a 20% reduction which puts most people in the range of 10-12 cal/lb (22-26.5 cal/kg).
However, those values are only estimates which have to be adjusted based on real world fat loss (I’ll discuss how I make adjustments in a later article). In modern times, with decreasing amounts of daily activity, I’m finding that many people, unless they engage in quite a bit of exercise during the day, find that even 10 cal/lb doesn’t generate significant fat loss. Because their true maintenance is lower than the estimate.
I have known people who have to go to 8 cal/lb (often with an hour of activity daily) to lose fat at any reasonable rate. So if you’re basing the 20% reduction on one of the estimation equations, that may be getting you into trouble. If your true maintenance isn’t actually 15 cal/lb, using a 20% reduction from that starting point won’t yield appreciable fat loss because true maintenance is lower than the equation is predicting.
A related issue is that, contrary to what some seem to believe, maintenance caloric expenditure is not static, it can vary somewhat with changing diet and activity (both up and down). During dieting, many people tend to move around a bit less during the day, due to fatigue and lethargy, and this reduces the pre-diet maintenance level, offsetting some of the supposed deficit.
An additional factor has to do with systematic mismeasurement of food. And here I’m not talking about people just grossly mis-estimating their food intake; rather, I’m talking about folks who are measuring the amounts of food they’re eating but making mistakes in their measurement (a point made in some detail in Leigh Peele’s Fat Loss Troubleshoot). If you’re using cup or teaspoon (or whatever your metric equivalent) measures to track your food, it’s very possible to end up eating more than you think because you’re still mis-measuring things.
A good example is peanut butter, if you load a tablespoon (supposedly 16 grams and about 100 calories according to the label) fully and then actually weight it on a digital scale, it will invariably be more than 16 grams. And since we all know that you actually overfill the spoon and and lick the sides, well….it’s easy to get a lot more calories than you’re actually writing down. And over the course of multiple meals per day, this adds up.
Depressingly, even vegetables, which are often thought of as ‘free foods’ on a diet, can be a problem in this regards. Due to hunger, some dieters start eating enormous amounts of vegetables (e.g. a head of cauliflower) and when you actually go look up the amount of digestible calories this provides, it does start to add up.
For smaller dieters who don’t have a huge deficit in the first place, it’s possible to eliminate the deficit almost entirely because of this type of thing. Correlating your cup/spoon measures on an actual digital scale may be necessary to make sure you’re not doing this. Yes, this is a pain in the ass and yes this starts pushing people towards insane levels of obsessive compulsive neuroticism. But in some cases it’s absolutely necessary to ensure that what you think you’re eating is actually what you are eating.
However, assuming that none of the above is the actual problem, what would I recommend someone in this situation do? It’s easy, if a 20% deficit is not generating reasonable enough fat loss, I’d suggest increasing the deficit by an additional 10% (this can be done by reducing calories or increasing activity a bit) for a month to see what happens. If that’s still not working, maybe go another 10% for a month. And if nothing has happened by then, I’d suggest getting some blood work done because something would appear to be profoundly wrong.
Of Whooshes and Squishy Fat
A few weeks back I answered a question about Not Losing Fat at a 20% Deficit, What Should I Do? and among other things, one comment I made had to do with a water retention that often occurs during fat loss which can mask fat loss and make it appear as if the diet is not working. I also mentioned specifically that I had written (with a straight-face no less) about whooshes in The Stubborn Fat Solution, along with a related phenomenon which I call squishy fat.In any case, to expand on that issue, I’m going to excerpt the chapter section from The Stubborn Fat Solution dealing with both phenomena. With that introduction, I give you (again, with a straight face)…
Of Whooshes and Squishy Fat
Before you freak out and think you’ve entered some weird Internet forum where people talk about stalls and whooshes, please bear with me; there’s actually some physiological rationale to what I’m going to discuss.
Many people have noted that fat loss is often discontinuous, that is it often happens in stops and starts. So you’ll be dieting and dieting and doing everything correctly with nothing to show for it. Then, boom, almost overnight, you drop 4 pounds and look leaner.
What’s going on? Back during my college days, one of my professors threw out the idea that after fat cells had been emptied of stored triglyceride, they would temporarily refill with water (glycerol attracts water, which might be part of the mechanism). So there would be no immediate change in size, body weight or appearance. Then, after some time frame, the water would get dropped, the fat cells would shrink. A weird way of looking at it might be that the fat loss suddenly becomes ‘apparent’. That is, the fat was emptied and burned off days or weeks ago but until the water is dropped, nothing appears to have happened.
For nearly 20 years I looked for research to support this, I was never sure if it was based on something from the 50’s or he just pulled it out of thin air as an explanation. Recently, one paper did suggest that visceral fat can fill up with water after massive weight loss but that’s about it.
Somewhat circumstantially, people using Bioimpedance body fat scales (which use hydration to estimate body fat levels) have noted that body fat appears to go up right before a big drop. This implicates water balance as the issue here.
As well, women, who have more problems with water retention, seem to have bigger issues with stalls and whooshes than men. Further, some individuals who have done dry carb-loads (high carbohydrate refeeds without drinking a lot of water) have seen them occur; presumably the body pulls water into the muscles and out of other tissues (fat cells). In lean individuals, appearance is often drastically improved with this approach, it doesn’t do much for those carrying a lot of fat.
I’d note that dry carb-loads suck because you’re so damn thirsty. Interestingly, even normal refeeds often work in this regards, perhaps the hormonal effect ‘tells’ the body to chill out and release some water. So not only do refeeds seem to improve stubborn fat mobilization the next day (as discussed above), they may help the body drop some water so that you can see what is happening.
Finally, many have reported whooshes following an evening which included alcohol. A mild diuretic, this would also tend to implicate water balance issues in the whoosh phenomenon.
I’d also note that this isn’t universal, lean dieters often see visual improvements on a day to day basis; a lot seems to depend on whether or not they tend to retain water in general. Folks who do have problems with water retention tend to have stalls and whooshes, those who don’t show nice consistent visual changes.
On a related topic, I wanted to discuss something else that often happens when people are getting very lean and dealing with stubborn body fat: the fat gets squishy, feeling almost like there are small marbles under the skin. Yes, very scientific, I know. That’s the best I can do.
As folks get very lean, down to the last pounds of fat, the skin and fat cells that are left will often change appearance and texture. It will look dimply (as the fat cells which are supporting the skin shrink and the skin isn’t supported) and feel squishy to the touch. This is bad in that it looks really weird, but it’s good because it means that the fat is going away. I have nothing truly profound to say about this topic, just realizes that it happens and usually indicates good things are happening.
