Have you ever wondered whether you have a slow metabolism? The concern
usually arises after you have tried to lose weight and were unsuccessful.
So, what is resting metabolic rate and how does it affect your ability to lose
weight? Simply put, it is the calories your body burns when you haven't eaten a
meal or exercised recently, and you are resting. Resting metabolic rate makes up
about 70% of the total calories you burn each day.
In this article, we will briefly look at 8 factors that impact resting metabolism.
Gender
Generally speaking, men have a higher resting metabolic rate than women, which is due to the fact that men are usually taller and carry more muscle mass on their frame compared to women. Women, on the other hand, have a higher body fat percentage by nature.
Genetics
There are people who seem to eat whatever they want and never gain a pound:
these fortunate people have genetics on their side, as some people are born with a faster metabolic rate and are more resistant to weight gain.
Age
It is not surprising that children have a faster resting metabolic rate than adults,
since they are actively growing and using more energy. Once you reach the age of 20, you lose the age advantage and your resting metabolic rate starts to slow down.
In fact, studies show that resting metabolic rate drops by about 2% each decade
after the age of 20. Women often experience a further slowdown in metabolic rate after menopause, which is why strength training is so important to preserve muscle mass.
Body Composition
When you lose body mass and your body has less total tissue to support and needs to burn less energy, you burn fewer calories each day. A person who has a higher ratio of muscle to body fat will also have a faster metabolic rate relative to
someone with a high percentage of fat and little muscle. Muscle uses up more
energy than stored fat when you're active and at rest.
Temperature
Working out in higher temperatures, for instance, practicing hot yoga, may help
you to burn more calories. As your body needs to cool itself and pump more blood faster, your body initially works more, and thus burns more calories. However, you should always keep in mind that working out in high temperatures dehydrates you faster: remember to keep a water bottle at hand.
Diet and Calorie Intake
Drastic calorie restriction can drop your resting metabolic rate by as much as 25%. When you deprive your body of energy and nutrients, it slows your metabolism to conserve your body's energy stores. Frankly, this explains why people lose weight early in a low-calorie diet, but then the weight loss slows down or stops. Your resting metabolic rate adapts to accommodate the amount of energy to which the body has access.
In contrast, eating a big meal will bump up your resting metabolic rate for a period of time. Every time you eat something, you get a modest metabolic boost due to the extra energy your body uses to digest, absorb, and metabolize the food you eat.
In addition, certain dietary components can cause a temporary boost in
metabolism. For instance, caffeine is a stimulant that activates your nervous system and boosts your metabolic rate. Some studies also suggest that green tea, due to its caffeine and catechins, raise resting metabolic rate. Every time you bite into a hot pepper, it not only creates body heat, it burns more energy for a short period of time. However, the metabolic boost is short-lived and is unlikely to have a meaningful weight loss benefit.
The Health of Your Thyroid Gland
Your thyroid gland is the master regulator of your metabolic rate. The average
woman has a resting metabolic rate equivalent to 1400 calories per day, while men burn around 1600 calories at rest.
However, hypothyroidism, an underactive thyroid gland, is more common in women after the age of 50. When the thyroid gland is underactive, it produces less thyroid hormone and that slows resting metabolic rate. A blood test that measures thyroid hormone levels is the best indicator of whether a person has this condition.
Exercise
Exercise has two effects on metabolism: first, it burns calories and therefore
contributes to the day's total calorie burn; second, it can also modestly boost your resting metabolic rate if you build more metabolically active muscle tissue. People who lose a significant amount of weight and maintain it usually say that they exercised to meet their goal. Additionally, studies show that exercise is important for weight loss maintenance in people who lose significant amounts of body weight.
The Bottom Line
Now you know the factors that control your resting metabolic rate. Keep moving
your body, continue strength training, and don't lower your calorie intake too much or you could end up slowing yours down. Also, should you be interested in some extra help in your weight-loss journey, take a look at our personal training services.
References:
Prog Mol Biol Transl Sci. 2018; 155: 85-107. Published online 2018 Feb 1. doi:
10.1016/bs.pmbts.2017.12.003.
Huffington Post. "A Fast Metabolism Could Make You Age More Quickly"
Medscape Family Medicine. "Can Diet and Exercise Really Change Metabolism?"