Where the worst type of fat is hiding in supermarket foods

Still a danger

Meanwhile, food manufacturers are allowed to use partially hydrogenated oils in their products, and so are restaurants. And if you're not savvy about reading Nutrition Facts labels, you may not detect the trans fat in your food. "The FDA doesn't require trans fat to be listed until there's a half gram or more per serving," explains McManus, "so the label may show zero grams of trans fat, even if a serving contains almost half a gram."

Are small amounts of trans fat dangerous? "It adds up, especially if you eat several foods with trans fat each day," says McManus. Based on FDA estimates, researchers at the CDC report it is possible that eliminating trans fats in the diet may prevent as many as 10,000 to 20,000 heart attacks and 3,000 to 7,000 deaths from heart disease each year.

What about other fats?

All fat is high in calories (nine calories per gram of fat, versus four calories per gram of carbohydrate, for example). A high-calorie diet can lead to weight gain, which can lead to chronic health problems.

An excess of saturated fats (such as those found in whole milk, butter, and red meat) can increase "bad" LDL cholesterol and lead to heart disease. Limit saturated fats to less than 7% of your total daily calories or less than 12 grams in a 1,500-calorie diet.

Some fats, within calorie limits, are good for you. Such "good" fats include monounsaturated fat (such as those in olive and canola oils, most nuts, peanut butter, and avocados) and polyunsaturated fat (for instance, in salmon, mackerel, walnuts, and safflower oil). Both are associated with lower LDL cholesterol and total cholesterol when substituted for saturated fats.