First, the bad news: Most of the hype about foods that boost metabolism really is just that—hype, at least when it comes to weight loss. Yes, you can drink ice water and your body will burn a few extra calories warming the water up to body temperature. And yes, you can chew gum and burn some calories working your jaw muscles. But even if you do these things all day long, you will not boost your metabolism enough to match the calorie burn of one good aerobic workout.
Now, the good news: There are a few healthy foods that really do boost your metabolism, in a modest way, and that can help you burn fat. Here they are:
Green tea. A number of studies confirm that drinking green tea can help you burn fat and lose weight. Green tea contains a number of active ingredients that affect how your body burns and stores fat. One component even inhibits your body’s ability to make new fat cells! Drink three to five cups a day of freshly brewed green tea. Caffeinated green tea works better than decaf. In fact, any food that contains caffeine will rev up your metabolism a bit.
Hot peppers. Compounds in hot peppers, called capsainoids, make your mouth burn. They also cause your body to generate heat. They promote the release of stored fat into the bloodstream, making it easier for cells throughout your body to use fat for energy–and get rid of it forever. The best way to get this effect: eat a couple of hot peppers and then exercise. Adding hot peppers will help you burn an additional 100 or so calories, and, over time, give you a slight edge in reducing body fat.
Garlic. Like hot peppers, garlic is thermogenic. It makes your body generate heat, which burns calories. Garlic revs up an enzyme called AMP-activated protein kinase that regulates metabolism. This enzyme targets many areas of the body, including muscles and a form of fat called brown fat, which produces heat and burns off calories. Garlic works best for weight loss if it’s eaten raw. Add raw garlic to salad dressings or foods like hummus, bean dips and salsa. Or add it just a minute or two before you’re finished cooking a stir-fry or pasta sauce.
And there's even more good news…Just plain eating boosts metabolism.
Any food increases your metabolism for a short period of time after you eat it. It’s an effect called post-prandial thermogenesis–and that means, simply “post-meal heat production.” It’s calculated as the number of calories required to metabolize, or break down and absorb, the food you’ve just eaten. It is usually less than 10 percent of the calories you have eaten.
If you are trying to lose weight, there are two things you should know about post-meal heat production: Protein has the biggest effect, and fat has the smallest. (Carbs are in the middle.) That means that a high-protein meal uses up more calories during digestion than does a high-fat meal, which truly can go directly to your hips if it’s not being used immediately to produce energy. It’s also the reason that eating too few calories when you’re dieting will often lead to slowed metabolism and stalled weight loss.