10 False Nutrition Facts Everyone Knows

Fat-free Foods are Better for Dieters
Dietician Jennifer Shea (L) from Shaw's/Star Market and Nora Saul, nutrition manager from Joslin Diabetes Center, look at the ingredients in yogurt at the store's location in Cambridge, Mass. Sometimes fat-free doesn't mean less calories. Wendy Maeda/The Boston Globe via Getty Images

If you're watching your waistline, chances are you've stocked up on a few helpers: fat-free salad dressing, "lite" mayonnaise and low-fat cookies. Unfortunately, as you munch your way through that box of not-very-tasty fat-free mini-muffins, there are lingering doubts. If so much of what you eat is low-fat or fat-free, why aren't you losing weight?

It's because fat-free foods have a dark side. They may cut out the fat, but it's been replaced with sugar -- lots of sugar, which helps make fat-free foods more palatable. This isn't a better option because sugar is stored in the body as fat [sources: Glassman, Poulter].

Mistakenly believing low-fat foods -- defined as having less than 3 grams of fat per serving -- save calories can also lead to more consumption of the product rather than eating the full-fat version. In fact, some low-fat foods have almost as many (or more) calories and sugar as the regular version. Plus the sodium is often higher. For instance, the Dunkin' Donuts blueberry muffin has 460 calories, 44 grams of sugar and 450 grams of sodium. The reduced fat version has 410 calories, 40 grams of sugar and 620 grams of sodium [sources: WebMD, Dunkin' Donuts].