Trans fats are also created when unsaturated fats are heated to high temperatures, as in deep-fat frying. Although they are technically unsaturated fats, trans fats behave like saturated fats by clogging arteries and increasing the susceptibility of cholesterol to oxidize. When the American Heart Association advised Americans to give up butter in favor of “hearthealthy” margarine, it was sadly guiding people out of the frying pan right into the fire.

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