What is Metabolism and Can You Change It?

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When we talk about metabolism, what we are usually referring to is your Basal Metabolic Rate or your BMR.

Your metabolism refers to a complex series of chemical processes that convert food into energy as well as establishing the rate at which your body burns calories. Ultimately, your metabolism is responsible for how quickly or easily you gain and lose weight.

To get a bit more specific, these metabolic processes require energy.

They build up tissues, break down tissues and provide fuel for energy. The way we measure these metabolic processes is in calories per day. In other words, it's the number of calories you body expends every day to keep you functioning and alive.

Beyond Your BMR

While we talk about BMR, a more important and all-inclusive calculation is your RMR or your Resting Energy Expenditure. While BMR is how many calories your body burns just to exist, your RMR includes the total number of calories your body burns every day, also called your Total Daily Energy Expenditure (TDEE). Your TDEE includes your BMR, the thermic effect of food (TEF), non-exercise activity thermogenesis (NEAT), the thermic effect of exercise and excess post oxygen consumption (EPOC or the afterburn).

If that all sounds confusing, it kind of is. Think about it like this - Your TDEE includes your BMR, which may be partially based on genetics (although we can influence BMR), eating, exercising, moving around and how much afterburn you experience from your exercise.

For the record, the higher the intensity of the exercise, the greater the afterburn.

Can You Increase Your Metabolism?

You may have heard all kinds of (ridiculous) things that could increase your metabolism. Things like eating spicy foods, drinking green tea or dousing your foods with hot sauce. Those things may give your metabolism a little boost, but it won't last, so you can stop killing yourself with spicy things.

What does work?

Muscle Mass

Muscle is your body's main source for burning fat. Think of muscle like the furnace in your basement heating your entire house. The more muscle you have, the more calories you burn all day, without even trying.

You don't have to work like a bodybuilder to build muscle. Just try lifting weights 2-3 times a week. A simple total body workout will do to get you started.

Eating Protein on a Regular Basis

Your body works harder to break down protein than it does to break down fat and carbs, so the more you eat, the more calories you burn while digesting your meals. That doesn't mean you want to go too crazy. You do still need fat and carbs to function well.

Here's a great list of high protein foods and the amount of protein in each serving size.

Eating Smaller, More Frequent Meals

There's some evidence that eating more frequently will also increase your TDEE while skipping meals has the opposite effect. Skipping meals or not eating enough actually slows down your metabolism, which is why it's so important to eat regularly throughout the day.

High Intensity Interval Training

Finally, one other thing that can increase your RMR is HIIT. This type of training takes you well out of your comfort zone, at least for short periods of time, and doing that taxes your body to the point where you burn extra calories after your workout just to bring your body back to its normal state.

You don't need to do HIIT every day - In fact, that's a bad idea because it can lead to injury, burnout and overtraining. However, doing it a couple of times a week is a great way to work on that metabolism.

Sources

American Council on Exercise. ACE Personal Trainer Manual, 5th Edition. San Diego: American Council on Exercise, 2014. p. 334

Kelly, Mark P., Ph.D. "Resting Metabolic Rate: Best Ways to Measure It-And Raise It, Too." American Council on Exercise. ACE.

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