Expertise Fitness and Wellness. Frequently asked questions. Giselle Castro-Sloboda Fitness and Nutrition Writer.

Metabolic rate and dieting -

But there are a lot of myths related to the impact metabolism has on your health, especially in terms of weight loss. In simple terms, metabolism is the internal process by which your body expends energy and burns calories.

This process works at different intensities in different people. How fast your metabolism works is determined mostly by your genes. Chih-Hao Lee, professor of genetics and complex diseases at Harvard's T.

Chan School of Public Health. Age also affects metabolism, as it can slow over the years, even if you start out with a fast metabolism. Differences in metabolism speed are evident in how easy or hard it is for people to gain or lose weight. A slow metabolism burns fewer calories, which means more get stored as fat in the body; that's why some people have difficulty losing weight by just cutting calories.

A fast metabolism burns calories at a quicker rate, which explains why some people can eat a lot and not gain extra pounds. But you can't entirely blame a sluggish metabolism for weight gain, says Dr. Is it possible to speed up a naturally slow metabolism, or rev up one that has become sluggish over time?

That, along with adopting a healthier diet and making sure you get enough exercise, may give people the extra push they need to lose and maintain weight. Pick up the pace. Add some high-intensity interval training to your regular routine. After a period of interval training, your metabolism can stay revved up for as much as a full day.

For example, when you're walking or jogging on a treadmill or outside, speed up for 30 to 60 seconds, and then slow to your usual pace; repeat the cycle for eight to 12 minutes. Eat protein and do weight training. Your metabolism increases whenever you eat, digest, and store food, a process called thermic effect of food.

Protein has a higher thermic effect compared with fats and carbohydrates because it takes longer for your body to burn protein and absorb it.

It's not clear how much of an effect protein has on metabolism, but studies suggest the best approach is to combine adequate protein intake with weight training, which increases muscle mass — and that also can boost metabolism. The loss of lean tissue muscle when you diet — which burns around calories per kilogram each day — lowers resting metabolic rate , meaning you need fewer calories than you previously did.

But the body also deliberately slows down metabolism to preserve energy stores and minimise weight loss. When the body senses depleted fat stores it triggers adaptive thermogenesis, a process which further reduces resting metabolic rate — and may stunt weight loss despite strict dieting.

Adaptive thermogenesis can kick in within three days of starting a diet, and is suggested to persist way beyond dieting — even hampering weight maintenance and favouring weight regain.

It showed that participants had a significant decrease in their metabolic rate, even several years after initial weight loss. Participants needed to eat up to calories less than expected daily. Other studies have also shown metabolic slowing with weight loss, but with much smaller decreases around calories fewer a day to maintain weight.

Research seems to show that most adaptive thermogenesis happens in the actual dieting phase as a temporary response to the amount of weight being lost. For example, one study on fasting diets showed metabolic rate indeed decreases as a result — but those who had the the greatest decrease in metabolic rate already had a higher metabolic rate to begin with.

Overestimaing metabolic rates at the start of a study or errors in predicting metabolic rate after weight loss could both also affect study results. When we lose weight, the main change we see is a decrease in body fat.

Church says. RELATED: A Scientifically Proven Way to Lose 1 Pound of Weight. It is typically determined only in laboratory settings, with people undergoing measurements in a darkened, temperature-controlled room immediately after 8 hours of sleep and 12 hours of fasting and reclining, according to the American Council on Exercise.

RMR is typically 10 to 20 percent higher than BMR, according to the NASM. RELATED: 21 Tips for Weight Loss That Actually Work.

Knowing your BMR or RMR can help you better determine your total daily energy expenditure in order to create a caloric deficit, defined as consuming fewer calories each day than you burn for energy.

A caloric deficit is required to lose weight. But because most people do not have access to state-of-the-art labs that are required to determine BMR, equations are often used to make approximations. The easiest way to measure your metabolic rate is to use an online calculator.

You can find many calculators online, and all use varying equations. The commonly used metabolic equation, called the Harris and Benedict equation, was first designed in and updated in While it was intended to estimate BMR, it actually estimates RMR, according to the NASM.

It uses height, weight, biological sex, and age to determine RMR and is based on average lean mass levels. The Mifflin-St Jeor equation is another equation that uses the same variables but may be more accurate, Church says. Other metabolic equations, such the Cunningham equation, use your total levels of lean body mass, which is a primary determiner of BMR and therefore RMR.

Calipers and smart scales are two popular at-home options, while the most accurate measures are performed in professional and laboratory settings. RELATED: 9 Hard Truths About Weight Loss That Can Help You Slim Down.

Men: For example, if a man is pounds, 5'11", and 43, his RMR is 1, calories. For example, if a female is pounds, 5'3", and 36, her RMR is 1, calories. For example, if a male is pounds, 5'11", and 43, his RMR is 1, calories. Women: 9. For example, if a man is pounds, 5'11", 43, and his body-fat percentage is 20 percent, his RMR is 1, calories.

For example, if a female pounds, 5'3", 36, and her body-fat percentage is 25 percent, her RMR is 1, calories. BMR or RMR can be used to estimate total daily caloric expenditure. According to the American Council on Exercise , after you determine your RMR, based on one of the above equations or an online calculator, you can multiply it by one of the numbers below, called activity factors:.

Figuring Metbolic your basal metabolic rate with a Rest and recovery or online calculator can Metaboolic you determine dietimg calorie deficit needed to help you Metabolci Rest and recovery. The dietinv of Natural ways to rev up metabolism you need eieting for your body Effective cholesterol control function Rzte called your basal metabolic rate, or BMR. If you know your BMR, you can better determine your caloric needs for healthy weight loss. You burn most of your daily calories with zero effort, movement, or even thinking. The calories used to maintain these basic bodily functions add up to your BMR. BMR — which is often used interchangeably with resting metabolic rate, or RMR more on that later — is one of many factors in the total number of calories you burn in a given day, also called your total daily energy expenditure TDEE.