Thermic Effect of Food

A CASE AGAINST CALORIES (Thermic Effect of Food)

Many aspects of metabolism are very difficult and even impossible to explain without a decent background in nutrition or biochemistry.  The thermic effect of food is not one of these concepts.  Once it boils down to it, it is ARITHMETIC.  Simple addition and subtraction.

The way it works, is that every food eaten takes a certain number of kcal to digest.  When it comes to digestion there is physical digestion and chemical digestion.  An example of physical digestion is turning the steak you just ate into a liquid, so that it can then continue throughout the digestive system, where it ends up in the blood (still a liquid, and why liquifying food is necessary for our bodys to function).  I know the following statement is drastically dumbing things down for those with any background education… but you can’t have solid chunks of undigested steak, bread, and corn floating around in your arteries.  This is why physical digestion is necessary.

Chemical digestion is the next step once food is liquified.  An example of this would be breaking down the more complex proteins in the steak into smaller peptides and aminos that can enter the bloodstream.  They then are used for repair, to fuel the muscle, or to undergo gluconeogenesis and become converted to carbohydrates for fuel.  (This entire paragraph is unecessary knowledge for physique transformation, so I’ll end that discussion right there.  A sentence or two on chemical digestion was necessary to put physical digestion into context).

As you can imagine, it takes the stomach kcal (energy) to digest foods from solid to liquid.  When your stomach “does work” it needs calories just like when your legs do work on the treadmill.  The energy deficit created by the stomach using calories to digest food (and therefore access calories) is called the “thermic effect” of the food.  Your steak may be 40 grams protein, 10 grams fat, for a total of 250 kcal (9kcal/g of fat 4kcal/g protein)….  Your muscle milk may be 40 grams protein and 10 grams fat as well, resulting in the same kcal “description” on the nutrition facts…  However, this does not take into account the thermic effect of the foods. 

I do not even have to look up the thermic effect of steak and muscle milk to know that steak uses more kcal to digest (because it is a solid).  This is why, while calories do matter, creating an effective diet is a hell of a lot more complex than calories.

And to be specific, this is why protein shakes are far inferior for fat loss to meat, despite the meat having a higher kcal “label” due to fat being included.  The protein shakes have little to no physical digestion to go through, because they are already liquified.

You may be burning 100 calories while digesting your 250 kcal steak.  You may be burning 4 calories with the muscle milk.


Typically, meats and foods that are highest in fiber have the highest thermic value.  Insoluble fiber is so hard to digest that humans cannot absorb it, this is why it is healthy for the intestines, cleansing, and detox.  That does not mean the human body does not try to digest it. (Thus using calories)

Foods such as broccoli, cauliflower, lettuce, celery, and spinach may have a negative energy balance once the thermic effect is taken into account.  This means the label on your broccoli that says “100 calories” should really say “-35 calories”.

Fruit also has a high thermic effect but due to presence of sugars and actual calories it would not become negative….  But rest assured the amount of kcal you are absorbing from the fruit is less than what is labeled on the nutrition facts.

Meat, also, may have the highest thermic effect of any food, and correspondingly also a very high digestion time.  Caloric labels on meat products may be the farthest off of the true energy value of the food.

This is why you do not see physique athletes taking “calories” into account as a priority while dieting down to minimal levels of bodyfat.

(References to “muscle milk” in this post were inaccurate in kcal, protein, and fat content.  I wrote this in 45 minutes, to make a point, and checking sources to be exact was unecessary).

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