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Date: | Fri, 31 Jan 2003 22:23:26 -0500 |
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> hunter-gatherers consumed high amounts (45-65% of energy) of animal food.
And
> “the fat intake would be comparable or higher (28-58% energy) than values
> currently consumed in modern, industrialized societies”
>
> Yet on page 11 of The Paleo Diet, Cordain lists the fat content of the
paleo
> diet to be 28-47%. I'm wondering why the 11% drop from what Cordain cites
> from his paper quoted from above?
% energy is a different variable that % grams of protein/carbs/fat
carbs - 4 calories per gram
protein - 4 calories per gram
fat - 9 calories per gram
For example, if fat constitutes 28% of one's daily intake (in grams), then
the energy (in calories) achieved is:
fat - 28% g x 9 cal/g = 252 cal
protein - 32% x 4 cal/g = 128 cal
carbs - 40% x 4 cal/g = 150 cal
total calories = 530 cal
% derived from fat = 252/530 = 47.5%
Thus, a fat intake of 28% (in grams) represents 47.5% (in calories or
"energy").
Since the range described is 28 - 47% fat (grams), let's look at the other
end of the range (47% fat).
fat - 47% x 9 cal/g = 423 cal
protein - 32% x 4 cal/g = 128 cal
carbs - 21% x 4 cal/g = 84 cal
total calories = 635
% derived from fat = 423/635 = 67% (calories or "energy")
Thus, a fat intake of 47% (in grams) represents 67% (in calories or
"energy")
In summary,
28% (in grams) = 47.5% (in calories or "energy"), while
47% (in grams) = 67% (in calories or "energy")
Now this % "energy" from fat range (47.5% - 67%) simply doesn't jive with
the range Cordain quoted in the paper as 28 - 58%. I guess this is a long
winded way of saying: I don't know.
Rob
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