Gabe Mirkin, M.D.
Please don’t be taken in by ads that say you will burn fat
instead of sugar while you sleep. Even if the products worked,
you burn so few calories during sleep that it is irrelevant whether
you are burning sugar or fat.
Your body burns primarily fat and sugar for energy. The
harder you exercise, the more sugar your muscles use. You use
the lowest percentage of fat when you exercise and the highest
percentage when you sleep. Your body converts fat into sugar
and sugar into fat, so the crucial factor is how many calories you
burn, and not whether you burn more fat or sugar. For example,
the average 150 pound person burns about 60 calories an hour
during sleep, compared to more than 600 calories per hour while
jogging. If you burn 80 percent fat during sleep, you will burn 48
calories of fat or one fifth of an ounce. If you burn 50 percent fat
when you exercise, you will burn 1.3 ounces of fat per hour or
more than six times as much.
There are many other products on the market today that
promise to help you lose weight. None will help you unless they
get you to exercise more and eat fewer calories. If you are
serious about losing weight, learn to eat lots of vegetables,
fruits, whole grains and beans; avoid concentrated sources of
fats, especially saturated fats and partially hydrogenated oils;
and stay away from refined carbohydrates (foods made with
flour, white rice or milled corn, and all added sugars). Start a vigorous exercise program that you can continue for the rest of your life.
10/4/05