Not all fat found in food is your enemy. Fat energizes your body, helps absorb nutrients and makes you feel full. Still, while some forms are healthful (such as olive oil), others are harmful. And trans fats are the most dangerous type.

Why They’re Bad: Trans fats raise your LDL—or “bad”—cholesterol more than other fats. And in one study, people who ate lots of trans fats gained extra jelly belly—the worst place to pick up weight because it contributes to heart disease.

What They Are: Certain shortenings and oils usually used to cook prepared foods, baked goods, snacks, fast foods and fried foods. There are two types: naturally occurring trans fats—which appear in tiny amounts in foods like butter—that aren’t that bad for you, and others, made by man, which are. The harmful trans fats (a.k.a. hydrogenated or partially hydrogenated oils) usually show up as shortenings and cooking oils that scientists have reformulated to keep them from spoiling as quickly in foods and your pantry.

What You Should Do: Now that researchers have discovered their relationship to heart disease, cities and school systems are banning trans fats from restaurants and cafeterias. Learn to recognize them in the chart at left. 

Learn to recognize the good, bad ad worst

  How to spot ’em: What they do: Where to find ’em:
Unsaturated Fats: GOOD They stay liquid at room temperature Raise the good (HDL) cholesterol in your bloodstream and reduce the bad (LDL) by scrubbing newly formed cholesterol out of your arteries Olive, fish, sunflower, corn, soybean and canola oils (some canola oils also contain saturated fat)
Saturated Fats: BAD Most stay solid at room temperature Raise bad (LDL) cholesterol in your blood Bacon, grease, lard, butter, cheese, whole milk, cream, fatty meats and coconut, palm and palm kernel oils
Trans Fats (man-made): WORST They can be liquid or solid at room temperature, so read ingredient labels. Look for the words hydrogenated or partially hydrogenated Raise bad LDL cholesterol, lower good HDL cholesterol and add fat to your midsection  Some shortenings, including original Crisco; many fast foods (think French fries), cookies, doughnuts and cakes; and many margarines, chips and snack foods


What does “0 trans fat” mean?

Even when a food label carries these words, the offending fat may be present. As long as they stay under ½ gram per serving, the Food and Drug Administration lets food manufacturers make the no-trans-fats claim. So check out the ingredients: If you see the words hydrogenated or partially hydrogenated oil, trans fats are present. And when eating out, ask whether the restaurant prepares food using any of the transfats listed in the chart above.