—Barbara Manning Lee's Summit, Missouri
A: Some research indicates that vinegar, which provides a diluted dose of acetic acid, slows stomach emptying and thus potentially prolongs the sense of fullness after a meal (presumably, this is true even if the meal is nothing but vinegar). Of perhaps greater interest, vinegar lowers the glycemic index of foods such as white bread and pasta, making them more filling, possibly because the carbs enter the bloodstream more slowly. Also, by giving the appetite center a flavor—astringent—vinegar makes the brain feel as if it were being fed. Evidence that vinegar helps with weight loss or self-control is hard to find, but these mechanisms do make the idea plausible. As for safety, because vinegar is acidic, it may irritate the esophagus and stomach. Over time too much acid may leach calcium from bone and damage tooth enamel. Generally, though, up to three tablespoons of vinegar a day—at only 9 to 15 calories total—should be fine.