Skip to main content
Jefferson Health

Home of Sidney Kimmel Medical College

What Is Metabolism? How It Works and Relates to Weight Loss

While metabolism may be the driver behind how your body uses and burns energy, many experts agree that focusing on metabolism alone can’t guarantee better health.

Metabolism has been framed as a key factor in weight loss and something you can “boost.” To help debunk this common misconception, understand how metabolism works and how much of a role it can play in sustainable weight management, we spoke with bariatric surgeon Dr. Marc Neff, registered dietitian Sara Hoffman and nurse practitioner Megan Price of Jefferson’s Bariatric Surgery and Medical & Surgical Weight Loss programs.

What is metabolism?

Metabolism breaks down and converts what we consume into energy. “It’s basically your body’s engine,” says Dr. Neff. “It runs your life.”

The metabolic process supports the body’s most basic, life-sustaining functions – such as breathing and blood flow – to the most complex actions, explains Price. Between 50-70% of this energy goes toward what your body does when it’s “at rest.” This is known as your basal metabolic rate (BMR). The remainder of your metabolic energy is used to digest food, exercise and perform your daily activities, adds Hoffman.

Metabolism is comprised of two more distinctive, simultaneous processes: anabolism and catabolism. Anabolism creates the “building blocks,” or molecules and energy stores, while catabolism breaks down larger molecules to provide energy to fuel anabolism and the rest of your bodily functions.

What can affect your metabolism?

Everyone’s metabolic rate is different, and it can be influenced by several non-modifiable factors – including genetics, age and sex – and modifiable factors, such as the food we eat, level of physical activity, sleep habits, body composition (muscle-to-fat ratio), certain medications and even stress.

Metabolic disorders, such as type 2 diabetes, hypothyroidism (underactive thyroid) and other hormonal and endocrine complications, can also disrupt the normal metabolic process. These can occur due to genetics or when an organ is diseased or damaged, explains Hoffman.

It’s also important to consider how metabolism can be indirectly impacted by our environment, notes Dr. Neff. “Your car would run differently if you were running it through the snow versus on a clear day, he explains. “The pandemic has been a huge culprit in hindering the way our bodies function. It’s changed our eating habits (our fuel) and our exercise habits (how we burn that fuel). Elevated cortisol levels, due to stress, can also increase our appetite.”

Can you have a ‘slow’ or ‘fast’ metabolism?

Your metabolic rate can potentially change with behavioral changes, but there are also evolutionary factors that come into play that we don’t know exactly how they work, explains Price. “If your metabolism is functioning at a faster rate, you’re going to burn food quicker – as opposed to storing it as fat,” Price says. “While this may seem more appealing in today’s society, historically, a slower metabolism was seen as more beneficial, because it was a means of survival – not starving.”

Can you ‘boost’ your metabolism?

Technically, yes. But it’s not a simple fix. There’s no “magic pill,” supplement or powder that’ll result in overnight changes, says Hoffman. If you see products that make these kinds of claims, you should be leery of them.

“It’s easy to blame a slow metabolism when you struggle with your weight, but having a faster metabolism does not guarantee a smaller body composition,” Hoffman continues. “Plus, changing your metabolism takes time and it involves focusing on a lot of other aspects of your health.”

A stereotypical short-term diet is actually detrimental for metabolism, explains Dr. Neff. “As you lose weight, your body interprets it as less food in your environment, so in order to survive, your metabolism slows. This is why many people hit a plateau during weight loss and have to adjust or ‘up’ their routine.”

“It’s also where you see ‘yo-yo dieting,’” adds Price. When you come off of any intense dietary restriction, your metabolism stays slow and takes time to adapt.

If you’re looking for ways to boost your metabolism, instead ask yourself if you really need to, suggests Price. It may not be as significant to weight loss as you think.

Metabolism vs. Sustainable Weight Management

Metabolism is just one factor in weight loss and weight management. It’s not solely about “calories in” and “calories out,” says Price. “It’s all about finding what works for you in terms of sustainable changes and finding balance – hormonal balance, balancing food and movement.”

Whether your metabolism is slow or fast, if you consume more calories than your body needs to function, they’re going to be stored, and it’s this stored excess energy that causes weight gain, explains Hoffman. If you’re trying to lose weight, you’ll need to burn fat stores, which takes nourishing your body with protein and fiber-rich whole foods, not skipping meals or restricting yourself.

What You Can Do

“The body is like a self-repairing machine,” says Dr. Neff. “For it to perform at its best, we have to put in the long-term maintenance. Remember, it’s not selfish to take care of yourself.”

Some key behavioral changes that Dr. Neff, Price and Hoffman recommend making – not only for better metabolism but overall health – include:

  • Be mindful of what you eat. A well-balanced diet should be full of whole foods (not processed foods) and focused on portion control, with treats in moderation.
  • Be active throughout the day. It’s recommended that adults fit in at least 30 minutes of cardiovascular activity five days a week; strength-training exercise three days a week is especially beneficial for metabolism.
  • Set a healthy sleep routine. Adequate sleep – between seven to nine hours – helps the body heal, regulates hormones, reduces stress and more.
  • Manage your stress levels with healthy coping mechanisms. Stress triggers your body to hold on to energy it could be burning, and it also increases cravings for unhealthy foods.

“Maintaining your health is like putting together a never-ending puzzle; the moment you think all the pieces are in place, life happens, and you have to rearrange them again,” says Price. “That’s why there are healthcare professionals and specialists in medical and surgical weight management. You don’t have to complete the puzzle alone.”

[Main photo credit:]

, ,
From the Experts