"Percent calories from xxx":
the latest nutritional hoax!

     From the same folks who brought you the horrendous lies about The Four Food Groups, the "need" for humans to consume dead, rotting animal corpses, bird menses, and bovine beverage, comes recently yet another totally useless, intentionally misleading, mathematically absurd, and only confusing concept: "Percent of calories from xxx".

     First, a calorie is nothing more, or less, that a unit of energy, just as the BTU, erg, foot-pound, joule, horsepower-hour, watt-hour, electron-volt, or Newton-meter are.  The term "calorie", as uniformly misused in the bizarre pseudoscience of orthodox nutrition, is really the kilocalorie: the amount of heat required to raise a kilogram of water one degree Centigrade.  The way the 'calorie content' of a substance is determined is to burn one gram of it to completion in high-pressure, pure oxygen in a Parr calorimeter bomb and measure the amount of heat released.

     How does this relate to human nutrition?  It really does not, because we do NOT "burn" our eaten food to completion, as always occurs in the Parr bomb.  Here, "burning to completion" means that all the carbon is burned completely to carbon dioxide, and all the hydrogen is burned completely to water; clearly this does not happen in human digestion!  In fact, since all proteins, fats, and carbohydrates are NOT used for energy, and are indeed used for other quite different purposes than producing energy, the abstract "calorie content" of "foods" and nutrients is absolutely irrelevant and meaningless.  Worse, thinking that one calorie-equivalent of protein, one calorie-equivalent of fat, or one calorie-equivalent of carbohydrate are in any way similar or identical, as seen by our digestive biochemistry, is simply absurd.  Would a 'calorie' of DDT, gasoline, wood, alcohol, diamond, feces, iron, or an old shoe, be somehow 'equivalent' to a calorie of protein, fat, or cho?  Obviously not.  Further, since a calorie is a unit of energy, it can NOT be "burned" as is foolishly claimed in the currently popular nutribabble about "burning calories"!.  What would you get?  Calorie oxide?

     Calories are a useful concept in thermodynamics and physics, but they are totally irrelevant to human nutrition or diet.   It makes as much sense to try to classify and/or quantify "foods" by their density, color, refractive index, shape, electrical conductivity, pH, heat capacity, tensile strength, compressive modulus, sheer modulus, melting point, boiling point, thermal conductivity, dielectric constant, absorption spectra, dipole moment, optical rotation, solubility, surface tension, thermal expansion, vapor pressure, viscosity, reaction kinetics, or any other -totally irrelevant- physical property as their "calorie content". 

     Next, we see that the "% calories as xxx" concept is similarly absurd and intentionally misleading.

     In the irrational pseudoscience called "Nutrition" we have of late seen such claims as:

Analysis: Soy Milk

8 fl oz Soy Milk

Wgt: 240 g (8.47 oz)
Water: 93%
Calories 79.2
Protein 6.62 g
Carbohydrates 4.37 g
Fat - Total 4.61 g, which leads to:

Calorie Breakdown
======-----------------0----------25----------50----------75----------100
Protein 31%                ########
Carbohydrates 20%    ######
Fat-Total 49%           ##############

     Where did these numbers come from??
     Calculate the calories from each major nutrient by multiplying grams of each by standard cal/gram calorie content of each.

     That's where the "percent of calories from protein, carbohydrate, and fat" figures actually come from.
     However, what do they MEAN??  ABSOLUTELY NOTHING!!
     In the entirety of scientific endeavor, numbers are used to compare quantities of various parameters, and generally if the quantities (numbers) of various parameters of two different entities are equal, we can generally imply some sort of equality, equivalence, or interchangeability between the entities.
     E.g. if both Mary and John earn $10/hr, we can say their hourly incomes are equal. Or, the 10 grams of protein from Food A is the same amount as 10 grams from Food B.

     But, in the wacky pseudoscience of orthodox nutrition, "foods" with identical "percent of calories from pro, cho, and fat" may be incredibly DIFFERENT and may provide VERY DIFFERENT amounts of pro, cho, and fat!!  Thus, comparing "foods" with identical "% of calories from xxx" profiles in any meaningful way is absolutely not possible, nor is there any meaningful relationship or understanding to be drawn by regarding these numbers!

     Example #1:

     Let's look at two hypothetical "foods":

     So, are we to believe that we get identical nutrition from each of these foods, if we eat the same amount of each, because their calorie profiles are equal?? NO!!
     Food #2 would provide 33 times as much pro, cho, and fat and 33 times as many calories! Food #2 is 33 times as nutrient dense as Food #1 even though the "percent of calories from xxx" are numerically identical.
     Further, one would get the same PCF profile from an infinite number of foods with the same weight ratios; i.e. 1.1/1.1/1.1, 1.11/1.11/1.11, ... 2.1/2.1/2.1, ... in spite of the fact that their absolute quantities of macronutrients were different.
     Biochemistry, and digestion, occur as a function of absolute quantities, not internal ratios of meaningless numbers.
     This is why the "percent of calories from xxx" is totally meaningless and, worse, leads only to confusion that obfuscates the differences between high-fat and low-fat "foods".

Example #2:

     Let's look at an even more dramatic numerical example that points out the absolute lack of meaning in the "percent of calories from xxx" fantasy.  We have a cup filled with water and add one drop of vegetable oil: then, percent of calories from fat = 100%.  We have a swimming pool a million times as big filled with pork fat: the percent of calories from fat = 100%.
     Are we really supposed to believe that because the calorie profiles are the same, that the effects from eating each are the same??

Example #3:

     One is generally interested in the quantity of a certain nutrient consumed per day: the RDA's are given in grams per day.  If we have a certain food with, say, 10% of calories as protein, how much of this food should we eat to get 20 grams of protein??  There is NO way to calculate this, since the absolute amounts of all nutrients are irreversibly lost when one goes from true weight percent to "percent of calories from ...".

Example #4:

     Just why was this meaningless pseudoscientific unit introduced to a public that is already very confused about what a healthful diet for our species should be?? To encourage the ignorant public to consume even more high-fat foods!

ttdd

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