Yes, you can teach your body to burn more calories — even while you sleep. Make a few simple changes to your diet and fitness routine and watch the pounds disappear.

By Nicole Gregory

Lose Weight Faster

Your best friend regularly eats doughnuts for breakfast yet remains maddeningly thin. You and your husband decide to lose weight together, and in two weeks he's lost 6 pounds and you've lost only 2. Your teenage son consumes everything in sight and just keeps growing taller, while you take two bites of chocolate cake one night and the next day the scale says you've gained 3 pounds.

Do you blame it all on metabolism and feel like simply giving up? Don't. While you may not naturally burn through calories like others do, making a few small adjustments to your exercise routine and diet can immediately rev up your metabolism — and help you lose weight.

Sound easy? It is. We'll tell you what you need to know to get started.

Can I Really Boost My Metabolism?

Yes. When your body turns the calories you eat into energy, it's called metabolism. To lose weight, and keep it off, you need to increase your metabolic rate — safely. Pills and supplements that claim to speed up this process may be dangerous. Like amphetamines and cocaine, these drugs artificially rev up the nervous system, and can exacerbate heart problems and even cause severe psychological problems, warns Jason Theodosakis, MD, assistant clinical professor at the University of Arizona College of Medicine in Tucson. The most effective way to naturally boost metabolism is through exercise, particularly the kind that helps build muscle. "Muscle burns calories at a higher rate than fat," says Leslie Bonci, RD, director of sports nutrition at the University of Pittsburgh Medical Center. So the more muscle you have in your body composition, the more calories you burn, even at rest. This is one of the miracles of exercise: Once you increase your resting metabolic rate, your body continues to require more energy for the basics of staying alive, such as breathing, digesting food, and pumping blood through your system. Even after you've taken a post-workout shower, changed clothes, had dinner, and put your kids to bed, your body keeps burning calories to cool down and repair itself, says Dr. Theodosakis.

How Come Some People Can Eat Everything Without Gaining Weight?

We all know people who rarely exercise yet never seem to have a weight problem. What's the deal? These are the factors that can make metabolism fast or slow:

Gender: Men naturally have more muscle than fat compared with women (even men who don't exercise), so their furnaces are always burning more calories. This is why men can generally get away with eating more and why they lose weight more quickly when they diet. The lesson? "You simply can't compare yourself with men!" says Bonci. Your body's needs will always be different from your husband's.

Age: Why is your teenager thin, no matter how many burgers or pizza slices he consumes? While kids are growing they burn more calories, says Michael D. Jensen, MD, an endocrinologist with the Mayo Clinic, in Rochester, Minnesota. On the other hand, once women enter their 40s their metabolism appears to slow. This is partly because estrogen and testosterone levels drop, causing a loss of muscle. "Muscle loss can be offset somewhat by strength training," says Dr. Theodosakis.

Genes: Is your thin friend a weight-loss genius? Probably not. She most likely comes from a thin family and may never have a weight problem. "The biggest predictor of how your body will burn calories is how much lean tissue you have, which you were born with or have built up in the gym," says Dr. Jensen. Lean tissue is everything that's not fat (muscle and bones).

Eat More Often And Lose Weight

It's not just what you eat but also how often that affects metabolism and weight loss. Read on for a day's worth of dining options that maximize calorie burn.

Breakfast > Eating an early-morning meal kick-starts your metabolism by turning on your digestive system (this actually burns calories). Plus, research from the University of Texas at El Paso found that eating 400-500 calories in the morning may keep you so satisfied you'll actually eat less the rest of the day.

Breakfast idea: A serving of whole-grain cereal topped with 1/3 cup blueberries and a cup of skim milk, plus a container of nonfat yogurt.

Snack > Eat three meals and three snacks throughout the day and you'll never feel starved, which can cause your body to hoard calories. And don't forget to drink H2O! One German study found that people who drank 17 ounces of cool water each day experienced an increase in metabolism. Researchers suspect that the body uses energy trying to warm the ingested water.

Midmorning snack idea: One tablespoon of peanut butter on 1 slice of whole wheat toast and 8 ounces of sparkling water.

Lunch > Eat a lunch that is light in calories but tastes good — enjoying your food is key to eating less.

Lunch idea: 1 cup reduced-sodium canned lentil soup, 6 tortilla chips with salsa, a small green salad, 1 orange, and an 8-ounce iced tea.

Snack > Include fiber (and protein) in every meal and snack, says Bonci. Fiber makes the body work hard at digestion, which increases metabolism. For instance, you burn more calories breaking down brown rice than white.

Afternoon snack idea: Three whole-grain crackers, 3 ounces low-fat cheese, and 1 cup nonfat milk.

Dinner > Beware: A big meal at night can overload your digestive system, causing some calories to be stored as fat.

Dinner idea: 5 ounces chicken, 1/2 cup pasta sauce, 1 cup whole wheat pasta, 1 tablespoon olive oil, and 1/2 cup broccoli. Eight ounces flavored sparkling water.

Snack > Don't go to bed hungry! Eating too little can slow your metabolism.

After-dinner snack idea: 2/3 cup chocolate frozen yogurt and herbal tea.

Copyright © 2008. Used with permission from the March 2008 issue of Family Circle magazine.