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Frozen dinners

"Read labels carefully when you're in the frozen-foods section," says Giancoli. They are likely to contain trans fat not just to make the foods more stable but also to give them a fattier feel in your mouth, she adds.

Frozen dinners and microwave meals are some of the biggest problems. Marie Callender's country fried beef, grilled chicken bake, tortellini Romano, and fettuccini alfredo dinners, for example, all contain at least 0.5 grams of trans fat each.

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