Wed, Dec-30-15, 12:55
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Senior Member
Posts: 3,025
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Plan: Optimal Diet
Stats: 00/00/00
BF:
Progress: 8%
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uh - no and yes.
No, it is not calories, if you mean, are we all identical calorie machines such that you can count the calories on the label of food, and exercise according to the calories on your treadmill's little display, and it works out right. That rarely lines up. Or that you can eat the same 4000 calories as the other person and expect the same result as the other person.
Yes, it is calories, if you mean, does food have calories. depends on the person and the metabolism. In your example, the person who does not gain weight on 4000 calories may increase their expenditure with NEAT and TEF and metabolic "wasting the calories as heat" . Whereas the person who gains, does not use the calories, but stores them. And it seems to have a genetic component.
I like what Lyle McDonald has to say. The calories-in-calories-out equation is wayyyyyyy more complex.
The Energy Balance Equation by Lyle MacDonald
Quote:
The Energy Balance Equation
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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
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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.
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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.
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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.
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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
Let’s look at each....
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Last edited by Seejay : Wed, Dec-30-15 at 13:13.
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