Yes, there are several factors that influence how fast your body burns calories at rest, and some of them are within your control. Your resting metabolic rate, the energy your body uses just to keep you alive, is shaped by your muscle mass, what you eat, how much you sleep, how active you are, and your hormonal health. Some of these you can adjust deliberately, while others shift naturally over time.
Why Someone Would Want a Slower Metabolism
Most metabolism advice focuses on speeding things up for weight loss, so wanting the opposite can feel like swimming upstream. But people who burn through calories quickly often struggle to maintain or gain weight, feel hungry constantly, or lose muscle during illness or recovery. In clinical settings, people with hypermetabolism (often caused by burns, infections, or overactive thyroid) are given high-calorie meal plans and told to limit physical activity to prevent their bodies from burning through energy reserves.
Understanding what actually controls your metabolic rate helps you make targeted changes rather than guessing.
Muscle Mass Is the Biggest Lever
Pound for pound, muscle burns significantly more energy at rest than fat does. One pound of muscle uses roughly 4.5 to 7 calories per day just sitting there, while fat tissue burns far less, somewhere around 50 to 100 times less than muscle per equivalent weight. This is why people with more lean mass tend to have higher resting metabolic rates.
If your goal is to lower your daily calorie burn, reducing intense resistance training can, over time, decrease your muscle mass and lower your resting rate. That said, this comes with real trade-offs: less muscle means less strength, reduced bone density, and poorer metabolic health overall. For most people, losing muscle deliberately isn’t a good strategy. A better approach is to keep your muscle but adjust your calorie intake upward to match what your body burns.
What You Eat Changes How Many Calories You Burn
Your body spends energy just digesting food, a process called the thermic effect of food. But not all foods cost the same amount of energy to process. Protein is the most metabolically “expensive” nutrient: digesting it increases your metabolic rate by 15 to 30 percent of the calories consumed. Carbohydrates raise it by 5 to 10 percent. Fats raise it by just 0 to 3 percent.
This means a diet higher in fats and lower in protein will result in fewer calories burned during digestion. If you’re trying to slow your overall energy expenditure, shifting your macronutrient balance toward more healthy fats (avocados, nuts, olive oil) and moderate carbohydrates, while eating less protein, will reduce the metabolic cost of eating. This won’t dramatically change your resting rate, but it chips away at total daily calorie burn.
Reducing Physical Activity
This one is straightforward but worth spelling out. Your total daily energy expenditure has three components: your resting metabolic rate (the biggest slice, usually 60 to 70 percent), the thermic effect of food, and physical activity. Of these, physical activity is the most variable and the easiest to change.
Cutting back on exercise, especially cardio and high-intensity training, directly reduces how many calories you burn each day. Even small changes matter: taking fewer steps, sitting more during the day, or switching from running to walking. If you’re someone with a naturally fast metabolism who’s trying to gain weight, reducing exercise while increasing calorie intake is one of the most reliable combinations.
Sleep and Hormones Play a Quieter Role
Sleep deprivation doesn’t slow your metabolism in a helpful way, but it does reshape your hormonal landscape in ways that change how your body handles energy. Consistently sleeping fewer than seven hours per night disrupts two key appetite hormones: ghrelin (which makes you hungry) goes up, and leptin (which signals fullness) goes down. The result is a body that constantly feels hungry and craves calorie-dense foods. Over time, this pattern is linked to a 38 percent increase in obesity risk among adults.
So while poor sleep doesn’t technically lower your resting metabolic rate, it creates conditions where your body stores more energy than it burns. That’s not the same thing as a “slower metabolism,” and it comes with serious health consequences including insulin resistance and increased inflammation.
Thyroid hormones have a more direct effect. Your thyroid gland essentially sets the dial on your basal metabolic rate. When thyroid hormone levels are low (hypothyroidism), your body burns fewer calories at rest, which often leads to weight gain. When levels are high (hyperthyroidism), the opposite happens. You can’t safely manipulate your thyroid function on your own, but if you suspect your metabolism is unusually fast, getting your thyroid levels checked is a reasonable first step. An overactive thyroid is a treatable medical condition, not just a personality trait.
Certain Medications Lower Metabolic Rate
Some prescription drugs slow calorie burn as a side effect. Beta-blockers, commonly prescribed for high blood pressure and heart conditions, can reduce heart rate enough to lower your daily energy expenditure. The degree of this effect depends on the specific medication and dose. Other drug classes, including certain antipsychotics and antidepressants, are well known for promoting weight gain partly through metabolic changes.
None of these should be taken specifically to slow your metabolism. But if you’re already on one of these medications and noticing changes in your weight or energy levels, the metabolic effect is a likely contributor.
Your Metabolism Will Slow on Its Own With Age
A large study published in 2021 tracked energy expenditure across the human lifespan and found that metabolism holds remarkably steady through early and middle adulthood. The real decline doesn’t begin until around age 60, when both resting metabolic rate and total energy expenditure start dropping by about 0.7 percent per year. By age 90 and beyond, total energy expenditure is roughly 26 percent lower than in middle-aged adults.
This decline tracks closely with loss of fat-free mass (muscle and organ tissue). So the age-related metabolic slowdown isn’t mysterious. It’s largely driven by the body gradually losing the tissue that burns the most energy. For younger adults worried about a fast metabolism, this natural trajectory means the problem is likely to ease over the decades without any intervention.
The Most Practical Approach
If your real goal is gaining or maintaining weight despite a fast metabolism, trying to slow your metabolic rate directly is less effective than simply eating more. Calorie-dense foods like nuts, nut butters, oils, whole milk, dried fruit, and avocados let you take in more energy without needing to eat enormous volumes. Eating more frequently, aiming for meals plus two or three snacks per day, also helps.
Reducing cardio while maintaining some resistance training preserves your muscle and bone health while cutting down on total calories burned. And shifting your diet toward more fats and carbohydrates (with moderate protein) slightly reduces the energy your body spends on digestion. Combined, these changes are more sustainable and healthier than any attempt to fundamentally suppress your metabolic rate.