Where the worst type of fat is hiding in supermarket foods

Trans fats are undeniably bad for health, and they're still in many foods.

nutrition label grocery shopping fat
Image: GPointsStudio/Thinkstock

Lurking on supermarket shelves, within colorful, seemingly harmless packages, is something that can cause serious harm to your health: trans fat. "No amount of trans fat is acceptable, from a health standpoint," says registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital.

About trans fat

Trans fats in the diet come mostly from partially hydrogenated oils. They're made by a process that uses hydrogen gas to turn vegetable oils into solids. This new form of fat extends a food's shelf life and improves flavor and texture. It's been a mainstay in processed foods—such as pastries, crackers, margarine, and corn chips—for decades.

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