How to Slow Down Your Metabolism

Determine your Basal Metabolic Rate (the energy burned while at rest). You can find the formula for this online or use the following calculations based on gender:

• Women: BMR = 655 + (9.58 x Weight kg) + (1.85 x Height cm) - (4.7 x Age years)
• Men: BMR = 66 + (13.7 x Weight kg) + (5 x Height cm) - (6.8 x Age years)

Calculate your daily caloric needs using the Harris-Benedict formula. Once you've determined your BMR, you can estimate your total calorie needs based on different activity levels. Slowing down your metabolism also means 'turning off' the body’s burning processes, thus reducing your energy requirements. If you are:

• Inactive or rarely exercise: Calories to maintain weight = BMR x 1.2
• Engage in light exercise 1 to 3 days a week: Calories to maintain weight = BMR x 1.375
• Engage in moderate exercise 3 to 5 days a week: Calories to maintain weight = BMR x 1.55
• Engage in intense exercise 6 to 7 days a week: Calories to maintain weight = BMR x 1.725
• Engage in vigorous exercise daily: Calories to maintain weight = BMR x 1.9

"Slow metabolism" does not directly cause weight gain. If you’re looking to gain weight, click here for healthy weight-gain tips. Most doctors agree that many other factors contribute to weight gain or loss, not necessarily metabolism. These factors include:

• The number of calories you consume daily.
• Your level and frequency of exercise.
• Genetics and family history.
• Any medications you’re currently taking.
• Unhealthy habits, such as poor sleep patterns.

Slowing your metabolism is not the healthiest way to gain weight. To slow down metabolism, you would need to do uncomfortable things such as skipping meals or reducing caloric intake. A medically sound way to gain weight should look like this:

• Increase caloric intake. Consume more calories than you burn each day.
• Address underlying health issues that may be causing weight loss, such as thyroid problems, diabetes, or anorexia nervosa.

Skipping meals. If you want to slow your metabolism, start by skipping meals. This is not a healthy way to decrease metabolism, but it is effective. Skipping meals causes the body to believe it is preparing for starvation, leading the metabolic rate to decrease in order to conserve energy.

Consume fewer calories. When you provide your body with fewer calories, it compensates by slowing down its overall metabolic rate. This makes sense because, when there isn't enough energy available, the body can't burn as many calories as it would with an abundant supply.

• Note: Reducing calorie intake may force your body to burn its own cells or muscle mass to make up for the calorie deficit. If you're already underweight, this method shouldn't be used to gain weight.

Get enough sleep. Each time you sleep, your metabolic rate drops significantly, and it continues to stay slow for a period even after waking up.

Replace simple carbohydrates (sugar) with complex carbohydrates (starches and fiber) when possible. Numerous studies show that sugar and fruit are digested and absorbed faster than complex carbohydrates, like those in bread, leading to sharp fluctuations in blood sugar levels. Research also indicates that complex carbohydrates (such as those in bread and corn starch) have a lower overall oxidation rate over a six-hour period compared to sugar.

• Sucrose (table sugar) also contains fructose, whereas complex carbohydrates consist solely of glucose. Eating fructose causes the body to generate more heat (burn more calories) compared to glucose.
• Choose fiber-rich foods like whole grains (especially whole-grain cereals) and leafy vegetables. A high-fiber diet can reduce thermogenesis in the body for up to six hours post-meal.

Add seeds to your meals. Among various food types, seeds are almost dry and serve as a rich source of healthy unsaturated fats. Seeds are among the most energy-dense foods, and you can buy them pre-packaged. It's observed that polyunsaturated fats oxidize more slowly than monounsaturated fats. Seeds are also high in the amino acid arginine. The body uses arginine to produce nitric oxide, a gas that helps slow down the metabolic rate.

Keep your body warm. Heat loss is a primary factor that depletes the body's energy, so wearing warm clothing is crucial for reducing your metabolic rate. In cold environments, the body automatically breaks down protein in cells, which impacts ATP synthesis and generates heat instead of producing useful energy from the food consumed.

• The cold also stimulates increased thyroid hormone production, which activates protein breakdown. Thyroid hormone is "the most important regulator of basal metabolic rate (BMR)," contributing to about half of the BMR value.

Hug someone if you're with others. Move to the warmest place or create a shelter if you're outdoors.

Stay still. Everything you do burns calories, even small actions like picking up firewood or stepping over rocks. After physical activity, your body continues to maintain a faster metabolic rate for some time, even when you're lying down resting. Walking one kilometer burns about 60 calories, but this figure doesn't include the increased metabolism caused by movement. So, try to sleep if possible.

Don't drink cold water or eat snow. Your body has to use energy to warm cold water. It's better to conserve that energy for vital activities that could save your life, like finding food or seeking an escape route.

• Stay calm. Even if you find yourself in a dangerous situation, it’s important to remain calm, as stress uses up energy. Anxiety triggers an increase in adrenaline and thyroxine, two hormones that significantly stimulate metabolism. This response is known as the fight-or-flight reflex.
• Avoid caffeine. Caffeine is a stimulant that raises your heart rate and accelerates metabolism.
• Stay warm, but don’t overheat. No matter how tightly you bundle up, always leave a little space for air circulation inside. If you overheat, your body will sweat and burn more calories, much like when you’re too cold.
• A moderate temperature (neither too cold nor too hot) is ideal for conserving energy. Research shows that the body uses energy most efficiently at temperatures between 24-27°C. At 20-22°C, even though it’s still within room temperature, your body generates more heat. Just a small temperature difference like that can increase metabolism by 2-5%. Temperatures from 28-30°C also boost metabolism similarly, causing your body to radiate more heat. The body doesn’t reduce heat production in hot weather (thyroid hormones control this process, and they are secreted at a constant rate), but instead, it generates even more heat due to other energy-consuming processes like sweating. Your body cannot reduce heat generation on demand to help you cool off or conserve energy.
• If you have hyperthyroidism, consider taking potassium iodide (120-300 mg of iodine per day). Before the discovery of antithyroid medications in the 1940s, potassium iodide was the only chemical compound used to treat hyperthyroidism. Antithyroid drugs like methimazole and propylthiouracil take weeks to reduce thyroid hormone production. The thyroid already stores a significant amount of hormones that continue to be secreted, even while new hormone production is limited by medication. Methimazole and propylthiouracil reduce thyroid hormone production but can’t stop the release of existing hormones. These medications can reduce metabolic rate to a level comparable to thyroidectomy within 24 hours. Potassium iodide can immediately block iodine absorption into the thyroid (the first step in thyroid hormone production), which is why it is used in radiation emergencies to protect the thyroid from radioactive iodine-131, a carcinogenic form of iodine.
• You can adjust your metabolism, but only to a certain extent. For instance, your metabolic rate will slow down when you sleep, but not as much as you might think: sleep reduces metabolism by 5-10% compared to resting while awake. Genetics play a role in metabolism, but not as much as commonly believed. Body composition has a far greater impact. Tall, lean individuals lose heat more easily than those with stockier builds. People with more muscle mass need more energy, which is why men typically eat more than women. Age also affects metabolism, but it’s out of our control—metabolism decreases by about 2% every decade. As a result, older people have lower caloric needs. Other factors such as ion pumping (like the sodium-potassium pump) also influence metabolism, but researchers still don’t fully understand this and are continuing to study it. Illness and menstruation are other uncontrollable factors that can increase metabolism and energy requirements.

• If you slow down your metabolism but continue to provide your body with the usual amount of energy, you will gain weight. Your body doesn’t require as much food when its metabolism is slow, so it stores excess energy as fat.