According to a study in the July 8 Journal of Agriculture and Food Chemistry, researchers found that mice who were fed a high fat diet and at the same time given acetic acid (the main component of vinegar), gained 10% less body fat than mice who weren't given acetic acid. It's believed that acetic acid fights fat by activating genes that produce proteins involved in the breakdown of fat. Other research on acetic acid suggests it may help control blood pressure and blood sugar. The bottom line: use a high quality vinegar as your salad dressing.