Grapefruit juice does not burn fat, despite the ever popular grapefruit diet. One study showed that obese people who ate grapefruit before a meal lost weight over a 12-week period, but scientists think it's simply the water in grapefruit that helps people feel full.
There is a lot of conflicting information concerning whether grapefruit helps burn fat, but there are not any scientific studies to support the claim. People who eat fruit instead of junk food or drink juice instead of a soda may lose a pound or two. Eating small, healthy meals multiple times per day stabilizes blood sugar levels and boosts the metabolism, which does cause weight loss.