Even as Americans have been gaining weight, they have cut their average fat intake from 36 to 34 percent of their total diets in the past 15 years. And indeed, cutting fat to control or lose weight makes sense. Fat has nine calories per gram.Protein and carbohydrates(碳水化合物) have just four.Moreover, the body uses fewer calories to metabolize fat than it does to metabolize other foods. Compared with protein and carbohydrates-which break down into amino acids and simple sugars, respectively, and can be used to strengthen and energize the body - dietary fat is more easily converted to body fat. Therefore, it's more likely to stay on buttocks,thighs and bellies.
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