"I have a fast metabolism; I can eat and eat and stay skinny." Most of us have heard someone say this, and a majority of us have responded with annoyance and envy. But what is metabolism, and can we make ours run a bit faster? Taylor Newhouse, a registered dietitian with the Texas A&M School of Public Health, helps break down what you should know about your metabolism.

What is metabolism?

Your metabolism isn't just what keeps your bragging friend lean, it's the constant process that your body is using to keep everything functioning. Your metabolism is always running, even when you're sleeping.

"Your metabolism is kind of the engine that keeps your body going," Newhouse said. "It's the drive that allows your body to utilize the food and nutrients you put into it."

Some people do have faster metabolism than others, and that is the work of genetics and someone's lifestyle. Although there's nothing you can do about your genetics, there are ways to impact the lifestyle side and give your metabolism a boost to keep it running in high gear.

How can you improve your metabolism?

Because the metabolism's base rate is set by genetics, there's no quick way to rev it up; it cannot be changed without making some long-term lifestyle changes.

"We can manipulate our metabolism to a degree," Newhouse said. "It's like a campfire: just like we need to give a fire tinder and pieces of wood in order to keep it from slowing down and burning out, we need to fuel our metabolism as well."

If you're looking to boost your metabolism, then there are a few changes you can make throughout the day. Working out, hydrating and eating right can help with your overall health, but there are also specific habits you can foster in order to give it a boost.

"Eating your leafy vegetables and working out can definitely help your metabolism," Newhouse said. "Muscle burns more energy than fat, so lifting weights or anything else that builds muscle -- along with eating correctly -- can play a large role in how our body processes nutrients."

Apart from getting in more muscle-building workouts and eating better, another important habit to kick your metabolism into gear is not ignoring the most important meal of the day: breakfast.

"People tend to overlook how important breakfast is," Newhouse said. "We go all night without food, and our body can approach a fasting state, an episode where our body will withhold calories, if we wait too long to eat after waking up."

What can slow your metabolism?

If it's possible to speed up your metabolism, then it's equally possible -- and far easier -- to slow it down. There are many habits that are easy to fall into that can make your metabolism run at a slower pace. One of these happens in the late hours of night, and involves what you're not doing: getting enough shut-eye.

Sleep deprivation is one of the biggest epidemics in American society, with more than one-third of adults getting less than the recommended seven to eight hours of sleep each night. Sleep is not only crucial for your metabolism, but skimping on sleep can also lead to long-term conditions such as heart disease and diabetes.

"Sleep is one of the biggest factors that people seem to forget about," Newhouse said. "Even if someone eats well and exercises, if they don't get adequate sleep, then their metabolism won't run as efficiently."

Although snacks often have a bad reputation for being unhealthy, they are very important to keep you fueled and nourish your body throughout the day. Snacks should have some protein, fiber and carbohydrates and should not have too much salt or sodium.

"Eating snacks won't slow down your metabolism if you're eating the right foods," Newhouse said. "Healthy snacks -- such as nuts, fruit or vegetables -- have the nutrients to slow the rate of digestion, keep you feeling fuller longer and keep your body working to process the nutrients."

Stress can also indirectly lead to problems with your metabolism. People with high amounts of cortisol, a stress hormone, tend to be overweight, and being overweight can slow your metabolism. Lowering your cortisol levels can start a chain-reaction that can help your metabolism run more efficiently.

What does your metabolism do over time?

Believe it or not, metabolism -- just like the rest of our body -- goes through the aging process. As your metabolism slows, your continuous diet and exercise choices become more important.

While the cause for this is unclear, women entering menopause will experience a slower metabolism and can find it more difficult to stay at a healthy weight, which makes diet and exercise vital to healthy aging.

"Nothing changes overnight," Newhouse said. "It's a matter of making the small choices that can add up to try and negate the effects that are naturally slowing down your metabolism."

If you're worried about how your metabolism is affecting your lifestyle, contact your health care provider or sit down with a registered dietician to set up a plan for a healthier daily life.

Materials provided by Texas A&M University. Note: Content may be edited for style and length.

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