Several factors speed up your metabolism, and most of them are under your control. Your body burns calories through three main channels: your baseline resting rate (which keeps your organs running), the energy cost of digesting food, and all the movement you do throughout the day. Each of these can be nudged higher through specific habits.
Daily Movement Matters More Than Exercise
The biggest variable in how many calories you burn each day isn’t your gym routine. It’s everything else you do: walking, standing, fidgeting, carrying groceries, climbing stairs, even gesturing while you talk. This category of calorie burn, called non-exercise activity thermogenesis (NEAT), can vary by up to 2,000 calories per day between two people of similar size, age, and body composition.
For someone who sits most of the day, NEAT accounts for roughly 6 to 10% of total daily energy use, maxing out around 700 calories. A person who works on their feet can burn up to 1,400 calories through NEAT alone. Someone in a physically demanding job like agriculture can hit 2,000 calories or more, making NEAT responsible for over 50% of their total energy expenditure. The practical takeaway: finding ways to move more throughout the day, not just during a workout, has a larger metabolic impact than most people realize. Standing desks, walking meetings, parking farther away, and taking stairs all contribute to this number in a meaningful, cumulative way.
What You Eat Changes How Many Calories You Burn
Your body spends energy just breaking down and absorbing food. This is called the thermic effect of food, and it varies dramatically depending on what you eat. Protein costs the most to digest, increasing your metabolic rate by 15 to 30% of the calories consumed. Carbohydrates raise it by 5 to 10%. Fats are the cheapest to process, bumping your rate by only 0 to 3%.
This means if you eat 300 calories of chicken breast, your body might use 45 to 90 of those calories just digesting it. Eat 300 calories of butter, and digestion costs you almost nothing. Over the course of a day, swapping some carbohydrate or fat calories for protein can meaningfully increase the total energy your body uses. This is one reason higher-protein diets tend to support weight management even when total calorie intake stays roughly the same.
How Exercise Keeps You Burning After the Workout
Exercise burns calories while you’re doing it, obviously. But certain types of training also elevate your metabolic rate for hours afterward. This “afterburn” effect occurs because your body needs extra oxygen and energy to repair muscle tissue, clear metabolic byproducts, and restore itself to a resting state.
Both high-intensity interval training and resistance training (weight lifting) produce a significant afterburn. Research in aerobically fit women found that both types of exercise kept metabolic rate elevated for at least 14 hours post-workout, burning roughly 33 calories per 30 minutes compared to a baseline of 30 calories per 30 minutes. That’s a modest but real difference that adds up over time. By 24 hours, metabolic rate had returned to normal in both groups. Steady-state cardio, like jogging at the same pace for 40 minutes, generally produces a smaller and shorter-lived afterburn.
Beyond the afterburn, resistance training builds muscle. Muscle tissue is more metabolically active than fat, so carrying more of it raises your resting metabolic rate permanently, not just for a few hours after a session.
Sleep Deprivation Slows Everything Down
Poor sleep disrupts the hormones that regulate hunger, energy storage, and metabolism. When you’re sleep-deprived, your body produces less leptin (the hormone that signals fullness) and more ghrelin (the hormone that triggers hunger). In one controlled study, just two nights of sleeping only four hours caused a significant drop in leptin and a significant rise in ghrelin compared to two nights of sleeping ten hours, even though participants ate the same amount of food. The result was increased hunger and appetite across the board.
Six days of sleeping only four hours per night reduced leptin levels by 19% on average and cut peak leptin by 26%. Sleep deprivation also raises cortisol (a stress hormone) in the evening and disrupts how your body processes blood sugar. These shifts make your body worse at using the energy you consume and more likely to store it as fat. Deep sleep is when your body releases growth hormone, which supports muscle repair and fat metabolism. Cutting sleep short means cutting that process short too.
Cold Exposure Activates a Hidden Calorie Burner
Your body contains a type of fat called brown fat that generates heat by burning calories. Unlike regular white fat, which stores energy, brown fat acts more like a furnace. It activates when you’re exposed to cool temperatures, and it burns a surprising amount of energy doing so.
A meta-analysis found that spending time at temperatures between 16 and 19°C (roughly 61 to 66°F) increased daily energy expenditure by an average of about 188 calories compared to sitting at a comfortable 24°C (75°F). Both the volume and activity of brown fat increased during cold exposure. You don’t need to take ice baths. Simply keeping your home slightly cooler, spending more time outdoors in cool weather, or turning the thermostat down a few degrees can activate this system.
Water Has a Small but Real Effect
Drinking water temporarily increases your metabolic rate through a process called water-induced thermogenesis. A study found that drinking 500 ml of water (about two cups) boosted metabolic rate by 30%. The effect kicked in within 10 minutes and peaked at 30 to 40 minutes. The total calorie burn from a single glass of water is modest, but if you drink several glasses throughout the day, it contributes to a slightly higher baseline. Staying well-hydrated also supports every other metabolic process in your body, from digesting food to transporting nutrients.
Capsaicin and Caffeine
Spicy food and coffee both have mild metabolism-boosting properties. Capsaicin, the compound that makes chili peppers hot, has been shown to increase resting energy expenditure. In one study of overweight individuals, consuming capsaicin with meals over 13 weeks increased resting calorie burn by about 119 calories per day compared to a placebo. At more moderate, everyday doses, the effect is smaller, closer to 10 extra calories burned per day. Caffeine similarly raises metabolic rate temporarily, though the effect varies between individuals based on tolerance and genetics.
Neither substance is a game-changer on its own. But combined with other habits on this list, they can contribute to a small metabolic edge over time.
Your Age Matters Less Than You Think
A landmark 2021 study published in Science analyzed energy expenditure data from over 6,000 people ranging from 8 days old to 95 years. The results overturned a common belief: metabolism doesn’t meaningfully decline in your 30s or 40s. After adjusting for body size and composition, metabolic rate stays remarkably stable from age 20 to 60. The real decline begins after 60, and it’s gradual.
The metabolic slowdown most people blame on aging is actually driven by losing muscle mass and becoming less active over the decades. Both of those are largely preventable. If you maintain your muscle through resistance training and stay physically active, your metabolism at 50 can look very similar to your metabolism at 25.