"Unfortunately, there's no spigot you can turn on to flush excess calories out of your fat stores" and speed up your metabolism, says Gabriele Ronnett, M.D., Ph.D., the founding director of the Center for Metabolism and Obesity Research at the Johns Hopkins University School of Medicine, in Baltimore. But you can keep your metabolism stable—and maybe even give it a bit of a boost—by making gradual changes to your lifestyle. Doing so will help you maintain a healthy weight (or lose a little if you need to) while ensuring that your bodily systems keep humming along and doing their jobs well. Here, seven science-backed tricks.
1. Skip the 6 A.M. workout and sleep in instead.
Your resting metabolic rate is lowest when you are, well, resting and drops about 15 percent overnight, reaching its slowest point in the early morning. So if you're trying to lose weight, you might think it makes sense to skimp on shut-eye. "But there's a cost," warns Kong Chen, Ph.D., the chief for energy metabolism research at the National Institutes of Health's Diabetes, Endocrinology & Obesity Branch, in Washington, D.C. New research has revealed that sleep deprivation alters a person's hormone balances, stress levels, and appetites, among other negative effects. Case in point: When study subjects slept just four hours per night for six nights, the rate at which their bodies processed calories from glucose (or sugar) dropped by 40 percent, according to a 2010 evidence review published in the International Journal of Endocrinology. By sleeping at night, you charge up your metabolism to make the most of the daylight hours.
2. Get your exercise in through short bursts throughout the day...
Yes, long, strenuous workouts burn calories. But as soon as you finish one, your thrifty metabolism will try to bring those expended calories right back, in case you need them later. "As a result, you may unintentionally eat more or move less the rest of the day to make up for a big burn," says Arya Sharma, M.D., Ph.D., the chair of obesity management and research at the University of Alberta, in Edmonton.
The fix? Break your exercise into smaller, more frequent periods of activity. This will increase your active metabolism without causing a spike in appetite. You may also maximize a metabolic effect known as the after-burn: If you do one big workout per day, the after-burn is once and done. "But if you do three or four 10-minute workouts throughout your day, you kick-start that after-burn every time," says Sadie Lincoln, the founder of Barre3, a yoga, Pilates, and dance–inspired workout. You'll also build and keep lean muscle mass, which, when you're active, can burn as much as 20 times the calories as fat, says Chen.
3. ...except on days you splurge.
Went overboard at the buffet? In that case, you'll need to up the ante on that day's regimen. A 2013 study from the University of Bath, in England, found that adding a 45-minute run on days when participants ate 75 percent more than normal kept their blood sugar levels stable.
4. Put protein on almost every plate.
Digesting protein requires more energy than any other type of calorie, which makes it great for boosting metabolism. "The trouble is that to see a meaningful extra burn, you need to eat a diet that's 35 to 40 percent protein, which is hard to sustain and could even have negative health consequences," says Roberts. (A 40-percent-protein diet typically requires eating quite a bit of meat or tofu. Think four slices of bacon and eight egg whites. And that's just for breakfast!) A happy medium: Consuming fat, carbohydrates, and lean protein with most meals. Your body metabolizes each macronutrient differently. (Carbohydrates are the easiest to digest; fat requires slightly more work.) Eat all three together and your metabolism will chug along optimally.
5. Go easy on fried foods and sweets.
When you consistently take in too many high-carb and high-fat foods, your metabolism gets into a habit of storing the extra as fat. And once it's deep in that storage mode, it starts a process known as enzyme inhibition, which is the metabolic version of hoarding: Enzymes block the usual process of converting fat and carbohydrate calories into fuel and instead store more and more of them as fat. "At the molecular level, your system gets confused and starts to work less efficiently," says Ronnett.
6. Don't forget to snack.
Just say no to long waits between meals, as well as cleanses and detoxes. All of these can trigger that thrifty metabolic instinct to protect you against apparent famine. "Smaller, more frequent meals may also help on this front," says Sharma.
7. Swap diet soda for seltzer.
For every diet soda you drink on a daily basis, your risk of becoming overweight within the next decade may increase by 65 percent. One possible reason: New research on artificial sweeteners suggests that drinking diet soda may blunt your body's ability to process sugar, and that in turn throws off your metabolism.