脂肪替代物只會讓你更肥

Counting on food with fake fats to help you slip into last year’s bathing suit? Better count again. Because a new study with rats shows that low-cal fat substitutes can actually promote weight gain. The work appears in the journal Behavioral Neuroscience. [Susan Swithers, Sean Ogden and Terry Davidson, "Fat Substitutes Promote Weight Gain in Rats Consuming High-Fat Diets"]

Dieters can choose from an array of snacktackular options in which sugars and fats are replaced by artificial, low-calorie substitutes. That sleight of hand seems ingenious. You can let your body think it’s getting the sweets and fats it craves while keeping the calorie count to a minimum.

But the new study suggests that this strategy is likely to backfire. Rats that consumed a mix of full-fat chips and chips with olestra wound up eating more and got fatter than rats that noshed on regular chips alone.

Their bodies were apparently getting mixed messages. A mouthful of fat is usually a signal that calories are coming, and the body reacts by getting ready to burn fuel. But olestra, which tastes like fat, carries no calories at all. So the body soon learns to stand down in the face of fat. All fat. Even real fat. Because as Shakespeare almost said, a chip by any other name still swells your seat.