If you truly want to win big in the fat-loss game, you’ve got to boost your metabolism. Burn more calories each and every day—whether you’re crushing it in the gym or chilling on your tush—and fat loss is pretty much guaranteed. But how does your diet tie in? We asked the experts to break down what to eat to rev your inner calorie-burning engine.
Metabolism, put most simply, is the process by which our bodies convert what we eat into the energy we need to survive and function, explains dietitian Jim White, R.D., owner Jim White Fitness & Nutrition Studios. Our basal metabolic rate (BMR) is the number of calories our body needs to maintain basic functions (like keeping our organs running). It accounts for the bulk of our total metabolism. From there, exercise, digestion, and any movement we do outside of the gym also contribute to our total calories burned. (This total is called ‘total daily energy expenditure.’)
If you want to significantly increase your total daily energy expenditure, you’ve got to increase your BMR. Sure, burning more calories during your workouts and getting more steps in helps, but boosting your BMR has a much bigger impact on the bottom line. And one major way to do that: protein.
Protein: A Metabolism Unicorn
Before we get into metabolism-boosting superfoods, there’s one food you should focus on if you want to burn more calories: protein. Not only do you burn extra calories just digesting the nutrient, but it can also help you increase your basal metabolic rate over time.
The Thermic Effect Of Protein
The calories you burn digesting your food—called the thermic effect of food (TEF)—account for about 10 percent of the total calories you burn in a given day. (That’s twice as much as the average workout.)
Thing is, different macronutrients have different thermic effects, White explains. Your body uses up to five percent of the calories in fat you eat, and up to 15 percent of the calories in carbs you eat just to digest them. But protein? Your body uses a whopping 20 to 35 percent of its calories during digestion! “For example, if you consume 200 calories of protein, your body will use between 40 and 70 of them just to digest it,” White says.
One 2015 Journal of Science & Medicine in Sport study of active women found that they experienced 30 percent greater TEF after eating a high-protein meal (45 percent calories from protein) than after eating a low-protein meal (15 percent calories from protein). Burn more calories every time you eat? Yes, please.
Protein And Basal Metabolic Rate
Even more significant than protein’s immediate effect on calorie-burning, though, is its ability to help increase basal metabolic rate over time.
“The key to boosting metabolism is to build muscle,” says Toronto-based dietitian and nutrition counselor Abby Langer, R.D. In fact, lean body mass is the number one determinant of metabolic rate. While every pound of fat burns two calories per day at rest, every pound of muscle burns roughly six. The more muscle you have, the more calories you automatically burn every single day.
Plus, not only does having more muscle boost your baseline calorie burn, but it also enables you to work out harder and longer, so you burn more calories during exercise, too.
Since your muscles are literally made of protein, you have to get ample protein from your diet (and strength train) if you want them to grow.
How Much Protein To Eat
“Without a sufficient supply of amino acids from dietary protein, the body begins to break down muscle and metabolic rate decreases,” White says.
For optimal muscle gain, one 2018 Journal of the International Society of Sports Nutrition study recommends eating 0.4 to 0.55 grams of protein per kilogram of bodyweight at least four times per day. If you weigh 180 pounds, that means putting back 132 to 180 grams of total protein per day.
What About Metabolism-Boosting Superfoods?
When it comes to boosting your metabolism through food, protein definitely takes the cake. Still, researchers and dieters alike are constantly hunting for other metabolism magic bullets.
In the lab, many of these metabolism-friendly foods (think green tea, ACV, and hot peppers) yield significant results, says Langer. Thing is, that doesn’t necessarily mean they work wonders in the real world.
Take green tea, which stimulates metabolism through an antioxidant called ECGC and its caffeine content, for example. According to one review published in Advances in Nutrition, you would have to drink roughly nine eight-ounce cups of green tea per day to increase your total daily energy expenditure by just four percent. (That’s about 80 extra calories if you normally burn 2,000.)
Of course, green tea is still worthy of your mug; its antioxidants fight free radical damage and have been linked to a lower risk of multiple forms of cancer. Just don’t expect it to make the fat melt off your body.
Spicy foods share a similar story. “Capsaicin [a compound found in chili peppers] speeds up the rate at which the body turns calories into heat to use for fuel, called thermogenesis,” White says. “However, the effect is slight.”
One study published in The American Journal of Clinical Nutrition found that people who consumed an oil containing capsinoid extract (capsaicin is a capsinoid) daily for 12 weeks didn’t see any bump in resting metabolic rate. However, their levels of abdominal fat decreased by 1.11 percent.
While concentrated amounts of capsinoids may offer some fat-loss benefit, eating mouthfuls of chili peppers will likely just leave you with a burnt mouth.
The Bottom Line
If you want to add a spicy kick to your foods or sip jumbo mugs of tea, go for it! It certainly won’t hurt your metabolism-revving efforts. Just remember to focus primarily on incorporating high-protein foods—like poultry, fish, eggs, and beans—into all snacks and meals.