Advice about dieting can come from many different directions at once. How do you sort out the good advice from the bad?

Laughingly, many believe that celery and chewing sugar-free gum can burn calories. Give your mouth a rest and get your body moving instead. Studies from prestigious organizations like the Mayo Clinic have debunked the “negative-calorie” myth that has upheld the gum and celery whispers.

Coffee, on the other hand, can rev up your metabolism significantly. Two cups of coffee, for instance, can cause the female body to expend 50 extra calories (in a 145 pound woman). Be careful though: sugar, cream and milk lessens the metabolic effect of black coffee because it can cause insulin levels to rise.

Eating after 8 p.m. may or may not cause increased body fat. Caloric intake throughout the day determines what happens when that late-night snake is consumed. Be careful to not overeat at night, however, if your day meals are light. This will reverse any beneficial effect.

Exercising on an empty stomach can burn more fat, but a better workout awaits if one eats a good meal beforehand. University of Ottawa researchers asked test subjects to treadmill until 400 calories were eliminated. While those who skipped breakfast burned 58 percent more fat, although fasting doesn’t always turn into significant weight loss.