Metabolism is one of those topics that sort of looks like a messy, cluttered house. There’s just so much in there it can hard to make any sense out of it. Usually, when we talk about metabolism, we mean the processes your body uses to break down food and create energy. But, it's not so simple as calories in/calories out. Why can your skinny best friend eat sweets all day long and never gain an ounce? And, why can’t you lose weight eating only dry salads for two weeks? Do you wish you could increase your metabolism?

How quickly or slowly your body burns calories (your metabolism) depends on many things. One of these factors is your basal metabolic rate (BMR), which is the how your body burns calories at rest, when it is just keeping your body alive. Your BMR is largely determined by heredity, but it is also affected by certain medications as well as some diseases, such as thyroid disease.

But you can certainly impact your metabolism by your lifestyle. You can slow it down or rev it up.

Dieting is a great way to slow down your metabolism. When you significantly restrict calories, your body reacts quickly by slowing down the rate it burns available calories, and holding on to its stored energy (also known as fat). This is the famine factor. When your body senses a shortage of available food, it works to keep you alive by slowing down its consumption of food (or energy).

You can also increase your metabolism. Primarily, building muscle, exercising and eating can speed up your metabolism and help you burn calories more quickly.

Muscle burns more calories than fat. This is the primary reason men lose weight much more quickly than women. Overall, they have much more muscle tissue than women, so they burn more calories more quickly.

Building muscle does not “turn fat into muscle”, as you might have heard. Exercising, particularly strength training, makes your muscles bigger and muscles burn more calories (even when they are not working) than fat. Having more muscle means you burn more of the calories you consume (storing fewer of them as fat), or if you do not consume enough calories, you burn your body’s stored energy (which is fat).

Exercising more also increases your metabolism. Moving your body requires additional energy. You will burn more calories with walking than you will when sitting, for example. But, you will also get added benefits from exercise which help you burn even more calories. Exercising causes your body to heat up, thereby increasing its calorie burning even after you stop exercising. This is called the thermal effect.

Eating increases your metabolism by the thermal effect, too. Your body works to digest food and this work increases your metabolism. This is why many experts recommend eating breakfast every day (to kick-start your metabolism after resting) and eating several small meals instead of just a couple of big ones. Of course, overeating or consuming more calories than you burn will negate any thermal effect you might get by eating often, so be careful here!

Essentially, your metabolism is always working, and you are always burning calories, even when sleeping. And, you may have inherited a slower metabolism or slowed yours down through dieting and/or inactivity. But, you can increase your metabolism again with just a few simple steps. Move your body and feed it properly and it will re-learn to be a calorie-burning machine. Start by taking a walk today!

The Biggest Loser has had great success in increasing contestants' metabolism with their workouts, like this one:



Learn the proper way to eat by making better food choices for life with the "You" docs: