If you’ve ever struggled with the numbers on the scale, you've probably blamed it on your metabolism. But what is metabolism exactly and how does it work? The term metabolism actually refers to all the processes in the body that use energy, according to the U.S. National Library of Medicine, but the word is most commonly used when we talk about weight. “When someone says, ‘I have a fast metabolism’ or ‘I have a slow metabolism,’ they’re usually referring to their ability to lose weight or maintain a normal weight,” says Caroline Cederquist, MD, a bariatric medicine specialist in Naples, Florida.
Most people can increase or decrease the rate at which they burn calories throughout the day, but many don't know how or that their gender, daily habits, and even health conditions can affect their metabolism. Here are 10 truths about metabolism which might just be the key to unlocking your healthy weight.
It's really about your resting metabolic rate or RMR.
Metabolism can refer to any of the chemical processes that take place in your body, but what most people are interested in is their RMR — the amount of calories you burn while just sitting around. Online calculators can estimate your RMR, but they don’t consider your muscle-to-fat ratio, Dr. Cederquist says. If you’re interested in a more accurate figure, consult your doctor for a calorimeter test, which measures the amount of carbon dioxide you breathe out, to determine your RMR. Or, you can try these 11 science-backed ways to boost your RMR right now.
Eating more protein may boost your metabolism.
While there are few superfoods proven to rev your metabolism, protein is one nutrient that actually may increase the amount of calories you burn. A 2012 study published in JAMA, the journal of the American Medical Association, found that people who were fed more calories than they needed tended to have higher RMRs when they followed a normal- or high-protein diet compared with those who followed a low-protein regimen. For the best effects, Cederquist says, choose lean proteins like chicken and fish over fattier cuts and consume smaller amounts throughout the day.
Simple carbs are metabolism busters.
Most everyone knows to stay away from doughnuts and sodas when trying to lose weight, but other simple carbohydrates — like white bread and crackers — can also slow weight loss, Cederquist says. When you eat them, your insulin levels rise. The insulin then encourages the body to store the sugar for later use — as fat. Choose high quality carbohydrates like vegetables, fruit, beans and legumes, and whole grains.
More muscle equals higher metabolism.
More muscle mass in your body translates to more calories burned, even at rest, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) explains. A study published in the European Journal of Clinical Nutrition in July 2015 found that nine months of strength training raised people's resting metabolic rate by about 5 percent. Haven't exercised in a while? Get started with these four easy muscle-building exercises.
Men tend to have a higher metabolism.
That's because men usually have more muscle mass and higher levels of testosterone, both of which influence calorie burning, Cederquist says. In a 2014 study published in the British Journal of Nutrition, men who were placed on a specific weight-loss regimen lost twice as much weight as women on the regimen during the first two months of the study. This can be particularly disconcerting when you're trying lose weight with a male partner, but don't let it dissaude you.
Menopause affects metabolism.
According to Cederquist, menopause can lower the body’s calorie-burning ability. When women go through menopause, their estrogen levels drop, which can lower their metabolic rate. It can also cause them to accumulate more belly fat. To reduce your overall caloric intake, sign up for Everyday Health's free Meal Planner, a tool that delivers daily recipes and meal ideas based on your weight-loss goal.
Many health conditions can influence metabolism.
Sometimes specific illnesses can affect the speed at which you burn energy, Cederquist says. People with hypothyroidism, for example, can have trouble losing weight because their bodies do not make enough thyroid hormone, according to the NIDDK. Graves’ disease, on the other hand, can result in too much thyroid hormone in the body and cause dangerous weight loss. If you're concerned about your ability to lose weight, ask your doctor to check your thyroid to rule out any issues at your next visit.
How much — and when — you eat can affect your metabolism.
If you’re skipping meals early in the day and then sitting down to a big dinner, you’re probably sabotaging your metabolism. “If you don’t eat all day and then eat a large meal at night, you’ll get a higher insulin response and you’re much more likely to develop metabolic dysfunction,” Cederquist warns. In a study published in The Journal of Nutritional Biochemistry in July 2015, researchers found that mice given their daily allotment of food in one large meal developed more metabolic problems and gained more abdominal fat than mice fed several times a day — even though the first group of mice ate less food overall than the second. Eat healthy breakfast, lunch, and dinner each day — and pack healthful, low-calorie snacks to nosh on in between meals.
Vitamin D may play a role.
Vitamin D is usually touted for its contribution to bone health, but research has shown that it could also play a role in metabolism and weight change. A 2013 study published in the European Journal of Clinical Nutrition found that vitamin D deficiency was associated with an increased risk of becoming obese.
A healthy metabolism promotes a healthy mind.
Aside from weight maintenance, a well-functioning metabolism comes with many other positive benefits, says Brian Quebbemann, MD, a bariatric medicine specialist with the NEW Program in Newport Beach, California. “The same hormones that affect our physical health, control mood, hunger, sex drive, and ability to cope with stress,” he says.