Weight Management Weight Loss What Is Metabolism? Change Your Metabolic Rate for Weight Loss or Maintenance By Malia Frey Malia Frey Facebook LinkedIn Twitter Malia Frey is a weight loss expert, certified health coach, weight management specialist, personal trainer, and fitness nutrition specialist. Learn about our editorial process Updated on April 15, 2021 Medically reviewed Verywell Fit articles are reviewed by board-certified physicians and nutrition and exercise healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Tyra Tennyson Francis, MD Medically reviewed by Tyra Tennyson Francis, MD LinkedIn Tyra Tennyson Francis, MD, is a board-certified family medicine physician and currently serves as the medical director of an outpatient clinic. Learn about our Medical Review Board Print B2M Productions / Getty Images When it comes to losing weight or maintaining your current weight, your metabolism can influence your results. If you're concerned about this, it's helpful to understand exactly what metabolism is. It's also beneficial to know what can affect it and, if yours might be slower, how to help speed it up. Metabolism Defined Metabolism refers to the biochemical processes that the body uses when converting food (calories) into energy to both sustain life and to support physical activity, whether exercise or non-exercise. These processes include: BreathingDigesting foodDelivery of nutrients to your cells through the bloodUse of energy by your muscles, nerves, and cellsElimination of waste products from your body The rate at which you burn calories or energy is called your metabolic rate. This number includes your basal metabolic rate (BMR)—the number of calories needed to support essential functions, like breathing and circulating blood—and calories burned during physical activity. Your BMR is the most significant component of your metabolic rate, accounting for 60% to 75% of your total calories expended daily. Factors Affecting Metabolism Everyone's metabolic rate is different, as many factors can influence how fast (or slow) our body uses or converts energy. Age Metabolism slows as we age. Some studies suggest that this is because our body composition changes as we get older. We gradually lose fat-free mass and, since fat burns fewer calories than muscle, our metabolism declines. Age-related changes in our organs can also reduce metabolic rate. Sex Males generally have a higher metabolism than females. Research indicates that this could be due to females conserving energy and storing fat more efficiently than their male counterparts, though it also appears that differences in various hormones may play a role as well. Body Composition Lean muscle mass burns more calories than fat, even when your body is at rest. So, the more muscle you have, the more calories you burn over the course of a day and the higher your metabolism. For people who are obese, energy expenditure can be impacted by inflammation. Body Size (Height) Your height can also affect your body's metabolic rate, but in somewhat complex ways. People who are taller tend to have a higher BMR (because they're bigger), but some research has found that they tend to burn less calories during exercise, relative to their body weight, compared to shorter people. When both your height and waist measurements are taken into consideration, it can help determine whether you're at risk of developing metabolic abnormalities such as metabolic syndrome. Body Temperature The body uses as much as 40% of its total energy expenditure in an attempt to keep its temperature stable. Therefore, if you are exposed to extreme temps, your body will have to work harder. Working harder raises your metabolism. People who are obese tend to have lower core temps, so some researchers suggest that this could have lowered their metabolism and contributed to their initial weight gain. Caffeine or Stimulant Intake If you've ever had too much coffee or too many energy drinks, you have likely felt your metabolism raise firsthand. This is because stimulants such as caffeine can increase your metabolic rate. Their risks can outweigh their benefits, though, so this isn't the safest way to boost your metabolism. Hormones If thyroid hormones are not produced properly by your body, your metabolism may increase or decrease. If the thyroid doesn't produce enough hormones (hypothyroidism), the metabolism slows, which may result in weight gain. Whereas, if the thyroid produces too much (hyperthyroidism), this typically contributes to weight loss. Pregnancy Women who are pregnant have a faster metabolism. This is due to an increase in body mass, as well as physiological changes in the body. If the woman starts out with a low body weight, her food intake may have to be increased to ensure that she gets enough calories and nutrients. Food Intake What's one of the first things most people do when they go on a diet? They cut calories and reduce their food intake. However, your body needs the nutrients in food to support a healthy metabolism. Metabolism also increases when food is being digested. Activity Level When you move more during the day, either through exercise or routine daily movements like walking or standing, your body burns more calories. The activity revs up your metabolism, making it easier to lose weight or maintain a weight loss. Your total energy expenditure can change from day to day depending on activity level, but your basal metabolic rate stays fairly steady. Calculating Your Metabolic Rate To determine your current metabolic rate, you first need to calculate your BMR, or the number of calories your body needs for basic functioning. The most accurate way to do this is to have it tested in a lab. Some health clubs offer metabolic testing as well (for a fee). Another option is to calculate your estimated BMR yourself. Online calculators are available or, if you'd prefer to calculate this number by hand, you can do so by using the Harris-Benedict Equation: Men: 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age in years) = BMRWomen: 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.330 x age in years) = BMR Once you have your BMR, you can figure out your total metabolic rate. This number is a combination of your BMR and the calories used for processes like exercise and other daily movements. Using a fitness tracker is the easiest way to add up the number of calories burned due to movement. If you burn 700 calories from daily movement, for example, and your basal metabolic rate is 1200 calories, your total energy consumption (metabolic rate) would be about 1900 calories. How to Increase Metabolism for Weight Loss There are some things that you cannot change about your metabolism. For example, you can't change your age or sex. But there are some things that you can do to boost your metabolism and lose weight. These include: Exercise: You burn more calories when you exercise. Even an easy workout increases your metabolism. Harder and more intense workouts burn more calories. Increase your daily movement: No time to exercise? Move more during the day. Simple daily tasks like walking, climbing stairs, gardening, and housework require your body to work harder and burn more calories. Add muscle: You can improve your body composition to burn more calories. Do strength training exercises to build muscle, and you can burn more calories all day long, even when your body is resting. Eat the right number of calories: Eating too many calories can cause weight gain. Eating too few calories can cause your metabolism to slow down. Make sure you're eating enough calories to maintain a healthy metabolism. A Word From Verywell Your metabolism will change slightly from day to day. If you can learn how to manage and maintain a healthy metabolism on a regular basis, it can be easier to achieve both weight loss and weight maintenance for the long term. How to Boost Metabolism in Different Ways Was this page helpful? Thanks for your feedback! Get nutrition tips and advice to make healthy eating easier. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 12 Sources Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. U.S. National Library of Medicine. Metabolism. Updated Apr 02, 2021. Comana F. Resting metabolic rate: How to calculate and improve yours. National Academy of Sports Medicine. Geisler C, Braun W, Pourhassan M, et al. 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Core temperature: A forgotten variable in energy expenditure and obesity? Obesity Rev. 2012;13(S2):97-104. doi:10.1111/j.1467-789X.2012.01040.x Liu A, Arceneaux III K, Chu J, et al. The effect of caffeine and albuterol on body composition and metabolic rate. Obesity. 2015;23(9):1930-5. doi:10.1002/oby.21163 Kawicka A, Regulska-Ilow B. Metabolic disorders and nutritional status in autoimmune thyroid disease. Postepy Hig Med Dows (Online). 2015;69:80-90. doi:10.5604/17322693.1136383 Most J, Dervis S, Haman F, Adamo K, Redman L. Energy intake requirements in pregnancy. Nutrients. 2019;11(8):1812. doi:10.3390/nu11081812 Kullman S, Kleinridders A, Small D, et al. Central nervous pathways of insulin action in the control of metabolism and food intake. The Lancet: Diabetes & Endocrinology. 2020;8(6):524-34. doi:10.1016/S2213-8587(20)30113-3 Additional Reading U.S. National Library of Medicine. Metabolism. Updated July 2, 2020.