In a message dated 10/4/02 9:05:25 AM, [log in to unmask] writes:

> But
>
>the practical significance of calories is this: No matter what the
>
>macronutrient composition of the diet, it is still possible that one is
>
>eating too much, and that is preventing weight loss.

I am reading a book called Body Heat by Mark Blumberg. He talks about
research on Diet Induced Thermogenesis, the phenomenon that's supposed to
keep us from obesity. Overeating induces DIT according to the research; the
body supposedly 'wastes' the extra calories via brown adipose tissue (BAT).
Studies on rats have found that when allowed to eat cafeteria style all they
want, they will eat 75% more food, but instead of gaining weight, their
metabolic output (heat) increases 75% so weight-wise it's a wash. Blumberg
says this implies that obesity results "from an inability to burn off excess
fat, not from mere overeating." Blumberg goes on to explain that wasting
energy is not all that's involved in preventing obesity. Apparently the
percentage of protein in the diet is crucial too -- but he suggests less,
not more. He says if a human had access to abundant sources of low protein/
high fat food -- he would store the fat, raise his leptin levels and then
stop eating. He should have a lot of energy from fat which he would burn off
as heat. But when he burned off the fat energy, he would be hungry again and
would eat another meal of low protein/high food, burn it off; eat a third,
burn it off until he had enough protein. Thus DIT is useful not only as a way
to prevent obesity, but to insure that we get  necessary nutrients.  Here's
the suprize: He claims that "For humans, when the diet is made up of 12%
protein, DIT is minimal (for rats it's 20%). Below these values, DIT
increases steadily. Above these values, heat production also increases, but
as by-product of the digestion of high protein diets; this is not DIT, but it
is wasteful. Thus the 12% and 20% values for the two species represent ideal
concentrations of protein for maximally efficient utilization of energy."
(p.185-6)

The trick might be to eat a diet comprised of no more than 12% protein and
the rest fat. We know that if carbs are thrown into the mix, we move into fat
storage territory which of course would have been great as a seasonal
response to carb supply to help us survive winter/non-fruting season coming
up, but it's something the majority of us probably don't need. I confess that
because of my years of low fat eating and the brain washing I've endured in
my Nutrtion education, I tend to 'justify' the fat that I eat as part of
eating protein -- it's still hard for me to eat just fat.

Namaste, Liz
<A HREF="http://www.csun.edu/~ecm59556/Healthycarb/index.html">
http://www.csun.edu/~ecm59556/Healthycarb/index.html</A>