From The Washington Post "Horizon" Section
HOW COME - Fat Facts -
Wednesday, September 8, 1999; Page H08
Q. Hope you can set us straight on the following question. There
are a lot of bragging rights involved. My daughter and her friends think
I'm nuts because I claim that it doesn't matter whether you eat a pound of
high-fat chocolate or a pound of low-fat anything, you will gain a
pound. They think that, if you eat a pound of chocolate, you can gain
more than a pound. I can't understand where the extra weight would
come from.
A. We referred this one to The Post's perpetually trim medical
writer Don Colburn. His report:
It's a good question, even if the bragging rights for both sides turn
out to be pretty low-cal.
Dad's basic argument -- that you can't gain more than a pound from
eating a pound of anything -- has at least an ounce of truth to it.
But it's not true that all pounds are equal when it comes to eating.
What matters for weight gain is how much energy content, measured in
calories, a food provides when it is absorbed by the body (and how
much energy the eater burns off through normal metabolism and physical
activity). People gain weight if they take in more food energy than
they burn off. Every extra 3,500 calories consumed -- whether from
chocolate or chop suey or chimichangas -- adds a pound of body fat.
A food's energy content per pound, known as caloric density, is the
key measure here. And caloric density varies widely from food to food,
says Ronald Krauss, head of molecular medicine at the Lawrence Berkeley
National Laboratory and former chairman of the American Heart
Association's committee on nutrition.
A 1.5-ounce Hershey milk chocolate bar has 232 calories. A pound of
chocolate -- about 11 Hershey bars -- would pack nearly 2,500
calories. By contrast, a pound of raw carrots provides only about 185 calories.
A pound of plain, skim-milk yogurt has 153 calories.
A food's total weight is not a good measure of its caloric punch.
Low-calorie carrots weigh a lot, but 88 percent of their weight is
water.
As veteran dieters know, it gets more complicated. Individual
metabolic rates differ. And not all calories are identical in their importance
to health. People with diabetes, for example, must pay special attention
to calories from sugar. People with heart disease may worry more about
calories from saturated fat.
Even dad's point about the impossibility of gaining more than a pound
by eating a pound of food, while literally true, may be more complicated
than it seems, Krauss points out. Eating something sweet, he notes,
"leads some people, at least, to want more. And one pound leads to
another."
