Flip through any magazine devoted to health or fitness and you’ll see articles with titles like “X Ways to Power Up Your Metabolism” or some other reference to boosting resting metabolic rate. Many people gravitate to titles like this as they are looking for an easy way to lose weight. What better way than to fire up your inner furnace and burn more energy?
But, if you read these articles, you may find the suggestions they offer are overhyped. The truth is that there are no “magic” ways to massively dial up your metabolic rate and turn your body into a fat-burning machine. But, there are ways to subtly increase how many calories you burn in a day. Let’s look at some metabolism-boosting habits backed by science.
Factors that Influence Your Metabolic Rate
How rapidly you expend energy depends on your resting metabolic rate and two additional components, the extra calories you burn due to exercise and the calories you burn when you eat something. Yes, you burn calories when you consume food as the food has to be digested and processed. But, your resting metabolic rate comprises the bulk of the energy you burn every day, around 70%
Unfortunately, most of the factors that impact your resting metabolic rate you have little control over. Genetics, body size, and gender are three major factors. Men tend to have a slightly higher resting metabolic rate than women, although differences in muscle mass may explain some of the difference. Age is another factor. Resting metabolic rate tends to slow with age. These are things you can’t change. But, what about things you can?
Boost Your Metabolism: The Type of Fitness Training You Do
Aerobic exercise is a calorie burner short-term, but strength training is a long-term investment in your metabolism. Muscle tissue is more metabolically active than fat and having more of it on your frame means you expend more energy. Mind you, the difference is modest, but it all adds up. For every pound of muscle, you add to your frame, you’ll expend an additional 6 calories per day. So, if you build up 12 pounds of muscle, you’ll burn an added 72 calories over the course of a day. It doesn’t sound like a lot, but over a year, it’s not insignificant. Of course, it takes time since women can build, on average, about a pound a month through strength training. So, the calorie-burning benefits are often overstated, but you will modestly boost your resting metabolic rate if you put on substantial muscle.
Switching high-intensity interval training for steady-state exercise will also give your metabolism a subtle boost for up to 24 hours afterward (some studies say up to a few days) due to EPOC (excess post-exercise oxygen consumption) or the after-burn effect. However, the spike you get in metabolic rate isn’t enormous, but it does add up over time. Don’t forget, high-resistance strength training creates an after-burn effect as well. The key is intensity.
Boost Your Metabolism: Get Your Thyroid Checked
Your thyroid gland, a butterfly-shaped gland, in your neck is the master regulator of your metabolism. If it thyroid function slows, you’ll burn fewer calories per day at rest. An underactive thyroid is relatively common in women after the age of 50 and the most common cause is Hashimoto’s thyroiditis, an autoimmune condition where your immune system attacks thyroid tissue. It pays to get your thyroid function checked via a blood test, especially after menopause as an under-active thyroid can be treated.
Boost Your Metabolism: Don’t Be an Aggressive Calorie Restricter
Aggressive calorie restriction to lose weight can have an unwanted side effect – it can slow your metabolism. Even weight loss itself slows your resting metabolic rate. Your body tries to protect you from starvation. When you’re not feeding it properly, it tries to make do with less and the rate that it burns energy slows, a phenomenon called adaptive thermogenesis. Remember, your body is an adaptation machine! Adaptive thermogenesis is one reason most people regain the weight they lose.
How much does your metabolism slow when you dial back on calorie intake? Losing as little as 5% of your total body weight can reduce your resting metabolic rate by 20%. Studies also suggest that the slowdown in metabolic rate persists as long as a year after an individual loses weight. That’s why people are sometimes able to keep the weight they lost off, initially, but it eventually comes back. Strength-training helps you prevent some of the metabolic slowing that goes with dieting as it preserves metabolically active muscle tissue. On the other hand, it’s hard to build muscle when you’re in a calorie restricted state.
Boost Your Metabolism: Change the Composition of Your Diet
It takes more energy to break down, digest, and process protein relative to fat and carbohydrates. So, adding more protein to your diet boosts the number of calories you burn when you eat a meal. As you might expect, this effect is subtle but it all counts. Some past studies suggest that the catechins in green tea modestly boost metabolism. In one study, participants that drank the equivalent of three glasses daily burned an additional 100 additional calories per day. Plus, green tea is a rich source of antioxidants.
The Bottom Line
If you’re discouraged by the fact that you can’t place your metabolism on fast track, heed the wise words of Dr. Chih-Hao Lee, professor of genetics and complex diseases at Harvard’s T.H. Chan School of Public Health. He points out that metabolism plays only a minor role in weight gain. Most of it can be blamed on a poor diet and too little physical activity. And, those are things you can do something about. So, take advantage of it!
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PennNutrition.com. “Healthy Weight/Obesity”
PLOS One. “Effect of Constitution on Mass of Individual Organs and Their Association with Metabolic Rate in Humans—A Detailed View on Allometric Scaling” July 26, 2011.
Harvard Health. “The Truth about Metabolism”
Agriculture and Agricultural Science Procedia. Volume 8, 2016, Pages 762-768.
The American Journal of Clinical Nutrition. Volume 97 Issue 3. (March 2013)