10 Things Dieters Need to Know About Metabolism

When you're trying to lose those extra pounds and keep the weight off, it's good policy to understand how your body uses the food you eat. Your metabolism is the way your body processes everything you eat and drink, converting all that sugar, protein and fat into energy. It's a never-ending, two-part process of anabolism and catabolism. Anabolism is when energy is created and stored, and catabolism is when energy is released. All of this is controlled by the endocrine system, the system in charge a lot of our body's processes, from cell and tissue growth and repair to reproductive function and mood regulation.

While you can't directly control how your metabolism works, you can control what you eat, how much you eat and how much physical activity you get every day. These three factors have a lot of power over your metabolism. It always comes back to diet and exercise, doesn't it?

Everyone's body works differently, and everyone will have a different metabolic rate. The trick is to figure out how fast or slow your metabolism is -- that's called your Basal Metabolic Rate (BMR) -- and then tailor your caloric needs and amount of exercise to suit how your body works

BMR is an important piece of how to work with your metabolism to lose weight because it measures how many calories you burn when you're doing nothing. (Remember, even when you're not active, your body is still using energy for breathing and other basic functions that keep you alive.) It's calculated based on your age, gender, height and weight factors.

Calculate your BMR with Discovery Health's Basal Metabolic Rate calculator.

Your metabolism is individual to you, based on a combination of your genetics, age, gender, muscle mass and certain environmental factors. While your best friend who seems to be able to eat anything and still stay slim seems to have a faster metabolism, it's not likely her metabolic rate creating such a difference. She's probably just found, either through work or good luck, the perfect ratio of lifestyle factors. She's working with a balance of how many calories she eats, how much she exercises, how much muscle mass she has and how much she sleeps. If she has that piece of pie after dinner every night without gaining a pound, she's probably also already slender, very physically active and getting lots of uninterrupted sleep every night.

When you skip meals or severely reduce the number of calories you eat, your body compensates by slowing down your metabolism, allowing it to save calories for energy your body will need to handle its basic functions. When you eat too many calories without also increasing your physical activity, those unused stores mean weight gain.

Basically, weight management comes down to this: the more active you are, the more calories you burn. That means how much physical activity you get in a day has more impact on your weight loss and gain than a fast or slow metabolism. When you're trying to lose or maintain weight, physical activity is one of the most important factors because it's under your control -- you choose how sedentary or active you want to be.

A 150-pound person who runs for 60 minutes (with a pace of a 10-minute mile) will burn about 680 calories, or roughly the number of calories in a Whopper from Burger King. But even the most sedentary among us is still burning calories, just not very many. Our bodies use about 10 percent of the calories from the foods we eat to process that food. Just don't count on that 10 percent to impact your waistline.

Muscle mass makes us strong, and as luck would have it, it also helps us burn calories -- during workouts and during downtime. Strength training, done with resistance to help build muscle mass, usually includes exercises such as weight lifting or using a resistance band. Adding strength training to your workout routine will help build muscle mass and keep your bones strong. One pound of muscle burns about 15 calories a day, and while that's still not much, it's more than what one pound of fat will do for you. Multiple studies have found that when strength training is added to our weekly exercise routines, our basal metabolic rate gets a boost.

It may not be your midnight snacks but rather your lack of sleep that's sabotaging your diet.

A study conducted at the University of Chicago found that when we don't get enough sleep, "sleep debt" changes the way our endocrine system functions. That includes our metabolism [source: Speigel]. And it's not good. Getting half of the recommended sleep -- four instead of eight hours of sleep each night -- for just six nights alters how our bodies regulate blood sugar levels and store energy so much that otherwise healthy participants suddenly began to show early symptoms of diabetes.

If you're normally getting about seven or eight hours a night, adding or subtracting about an hour won't make much of a difference. But if you're not getting more than four or five hours of sleep a day, add another two or more and kick start your weight loss.

As we age our metabolic rate naturally slows down, just another joke Mother Nature plays on us. According to researchers at the University of Colorado, sedentary postmenopausal women have roughly a 10 percent decrease in their BMR. That would help to explain the common complaint of women who are in their 40s and 50s: weight gain and an inability to lose weight as they were able to before.

To combat the impact age has on our metabolic rate, we need to step up our game -- beginning in our 40s, we need fewer calories, about 200 fewer, to help maintain our weight. And don't forget physical activity. No matter what our age, exercise and strength training are key to increasing metabolic rate and losing weight.

Your thyroid is a butterfly-shaped gland located below your Adam's apple. While you probably never think twice about what it does for you, when it starts to go wonky you'll wonder why no matter what your efforts are you just can't lose weight.

The way the thyroid works is that it releases hormones that control many bodily functions, including, you guessed it, your metabolic rate. When your thyroid gland slows down, even on the slow side of normal, your metabolic rate also slows down. Conversely, if it's overactive, your metabolic rate speeds up. Your primary doctor can test your thyroid function, and if needed prescribe synthetic thyroid hormones to help your lagging gland.

Caffeine gets both a good and a bad rap. When it comes to boosting your metabolism, it may help to brew up a pot of coffee. Caffeine is a stimulant, and many people find that it improves their alertness -- that's caffeine's affect on the central nervous system. Stimulants rev your engine, and that includes boosting your metabolism.

In addition, studies have found that green tea may boost your metabolism and help you lose or maintain weight, especially when combined with caffeine. Researchers at the Lausanne University in Switzerland found that study participants who drank three servings of green tea over a span of three days saw a 4.6 percent increase in their energy expenditure -- and that equals a boost in metabolism [source: University of Maryland].

Most dieters are used to keeping track of what and how much they're eating -- this is good, but with a few tweaks it could be better. What you eat won't likely directly impact the speed of your metabolism -- it's the total number of calories and your level of physical activity that will speed your weight loss.

To help boost your weight loss potential, choose foods that are high in protein (lean meats, fish, soy), fiber (pick whole grains over refined carbs) and low-fat dairy. Watch your portions and number of calories you eat in one day -- to lose one pound, you need to reduce your calorie intake by 3,500 calories, the amount of calories in one pound of fat. (Losing 500 calories from your diet a day for 7 days will translate into losing one pound in one week).

To figure out what's right for you try calculating your BMR and the Harris Benedict formula to get a good idea of your personal caloric needs. The more you know about how your body works, the better you can work with it.