On Sat, 25 Sep 1999, Ilya wrote:

> What you are saying here explains why SOME of the calories
> may not be used up in an extremely high caloric intake situation.
> (Bodys ability to utilize these calories maxes out). This does
> NOT explain why NONE of the calories above maintenance seem
> to be utilized (no fat/weight gain). My point was very simple -
> you were wrong when you said that the body does not simply
> discard calories, that they must be used or stored. I was
> trying to show that not only can they be discarded, but they
> are discarded in large amounts (everything above the needed level).

My recollection is that there is very little published research
on this question.  Lyle McDonald once posted an abstract of a
study that appeared to show that people on a high-fat ketogenic
diet would not gain weight until their caloric intake reached a
rather high level -- but there was still at level at which they
gained weight.  So there also appears to be an upper limit to
what is discarded.

At, say, 5,000 calories per day, most people are well beyond the
level at which their body can actually burn those calories
(unless perhaps they are Sherpa porters or something).  This
implies that thousands of calories of ketones are being discarded
via urine, breath, etc., each day -- *or* that significant
amounts of fat are leaving via the stool.

From a paleolithic standpoint, I tend to assume that the ability
to store energy as body fat had a high value.  Fat not only is
energy that can be used later but also serves as insulation.  The
colder climates where carbs are scarce are precisely the climates
where such insulation would be needed, so it would make sense
that we should have an ability to make body fat even under
low-carb conditions.

Todd Moody
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