Your cube mate advises against eating after 8 p.m., a girl from your yoga class swears by the grapefruit diet, and your best friend warns that mixing carbs and protein can pack on the pounds. Sure, you've been hearing diet tips like these from well-meaning people for years, but is there any truth to them? To set the record straight on the most oft-repeated advice, we consulted a team of nutrition experts. They revealed which strategies you should forget and which live up to their get-slim promise.





Q. Will chewing low-cal foods like sugar-free gum and celery help me burn calories?



A. It might, but hardly enough to trigger weight loss. Gum and certain veggies are often called "negative-calorie" foods because they supposedly take more energy for your body to chew or digest than they contain.



The negative-calorie myth was put to the test when researchers at the Mayo Clinic in Rochester, Minnesota, asked people to chew sugarless gum at a rate of 100 bites per minute. After calculating the energy expended (about 11 calories per hour), they concluded that a person who chomped on a piece every waking hour of the day for a month would lose less than a pound. As for celery? All that crunching does burn energy, but it amounts to less than the 6-calorie stalk contains. The bottom line: If you really want to shed pounds, give your jaw a rest and start moving your body.





Q. Can coffee really rev up my metabolism?



A. It's true: Java can stoke your calorie-burning furnace—provided you drink it black. A study in the journal Metabolism found that the caffeine in two cups of coffee ...