> 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