Which fats are you eating?

Conventional wisdom ("fat is bad for you") and food labels ("fat-free") are easy shortcuts at the grocery store, but they're not good enough for healthy eating. To keep your body toxin-free, you may have to do some homework, says Alyse Levine, a registered dietitian in Los Angeles. Some quick lessons on fat:

All fat is not created equal. Unsaturated fat can be good, saturated fat is usually bad, and trans fat is practically poison. Both trans fat and saturated fat raise LDL (bad) cholesterol, but trans fat lowers HDL (good) cholesterol to boot. The double whammy means that traces of trans fat -- even a 2% increase in your daily intake -- can increase your risk of heart disease by 23%.

Food labels can be misleading. " 'Zero trans fat' is one of the most deceptive statements you'll find on food labels," Levine says. Foods with less than 0.5 grams of trans fat per serving still get the "zero" OK from the Food and Drug Administration. The American Heart Association recommends no more than 2 grams of trans fat a day, so you could reach the maximum intake with just four servings of such foods.

Ingredient lists are giveaways. "Partially hydrogenated oil" and "shortening" both translate into trans fat, for instance. And some foods are more likely to contain these ingredients. Candy, crackers, cookies and fried foods are some obvious suspects, Levine says.