Slideshow: 10 Ways to Boost Your Metabolism

Boosting metabolism is the holy grail of weight watchers everywhere, but how fast your body burns calories depends on several things. Some people inherit a speedy metabolism. Men tend to burn more calories than women, even while resting. And for most people, metabolism slows steadily after age 40. Although you can't control your age, gender, or genetics, there are other ways to improve your metabolism. Here are 10 of them.

Your body constantly burns calories, even when you're doing nothing. This resting metabolic rate is much higher in people with more muscle. Every pound of muscle uses about 6 calories a day just to sustain itself, while each pound of fat burns only 2 calories daily. That small difference can add up over time. After a session of strength training, muscles are activated all over your body, raising your average daily metabolic rate.

Aerobic exercise may not build big muscles, but it can rev up your metabolism in the hours after a workout. The key is to push yourself. High-intensity exercise delivers a bigger, longer rise in resting metabolic rate than low- or moderate-intensity workouts. To get the benefits, try a more intense class at the gym or include short bursts of jogging during your regular walk.

Your body needs water to process calories. If you are even mildly dehydrated, your metabolism may slow down. In one study, adults who drank eight or more glasses of water a day burned more calories than those who drank four. To stay hydrated, drink a glass of water or other unsweetened beverage before every meal and snack. Also, snack on fresh fruits and vegetables, which naturally contain water, rather than pretzels or chips.

Some ingredients in energy drinks can give your metabolism a boost. They're full of caffeine, which increases the amount of energy your body uses. They sometimes have taurine, an amino acid. Taurine can speed up your metabolism and may help burn fat. But using these drinks can cause problems like high blood pressure, anxiety, and sleep issues for some people. The American Academy of Pediatrics doesn’t recommend them for kids and teens.

Eating more often can help you lose weight. When you eat large meals with many hours in between, your metabolism slows down between meals. Having a small meal or snack every 3 to 4 hours keeps your metabolism cranking, so you burn more calories over the course of a day. Several studies have also shown that people who snack regularly eat less at mealtime.

Spicy foods have natural chemicals that can kick your metabolism into a higher gear. Cooking foods with a tablespoon of chopped red or green chili pepper can boost your metabolic rate. The effect is probably temporary, but if you eat spicy foods often, the benefits may add up. For a quick boost, spice up pasta dishes, chili, and stews with red pepper flakes.

Your body burns many more calories digesting protein than it does eating fat or carbohydrates. As part of a balanced diet, replacing some carbs with lean, protein-rich foods can boost metabolism at mealtime. Good sources of protein include lean beef, turkey, fish, white meat chicken, tofu, nuts, beans, eggs, and low-fat dairy products.

If you're a coffee drinker, you probably enjoy the energy and concentration perks. Taken in moderation, one of coffee's benefits may be a short-term rise in your metabolic rate. Caffeine can help you feel less tired and even increase your endurance while you exercise.

Drinking green tea or oolong tea offers the combined benefits of caffeine and catechins, substances shown to rev up the metabolism for a couple of hours. Research suggests that drinking 2 to 4 cups of either tea may push the body to burn 17% more calories during moderately intense exercise for a short time.

Crash diets -- those involving eating fewer than 1,200 (if you're a woman) or 1,800 (if you're a man) calories a day -- are bad for anyone hoping to quicken their metabolism. Although these diets may help you drop pounds, that comes at the expense of good nutrition. Plus, it backfires, since you can lose muscle, which in turn slows your metabolism. The final result is your body burns fewer calories and gains weight faster than before the diet.