Terezie Tolar-Peterson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment. But does the speed of metabolism really vary all that much from person to person? This question is trickier than it might first seem — and whatever the current speed of your metabolism, there are things that will nudge it into lower or higher gears.
Metabolism is a biological term that refers to all the chemical reactions needed to maintain life in an organism. Your metabolism accomplishes three main jobs: converting food into energy ; breaking down food into its building blocks for protein, lipid, nucleic acid and some carbohydrate; and eliminating nitrogen wastes.
The energy value of a food is measured in calories. Basal metabolic rate is the minimum amount of calories required for basic functions at rest. So your total energy expenditure combines the two: your resting energy expenditure plus your energy expenditures for other activities.
The estimated daily caloric intake needs for an adult woman of pounds 57 kilograms range from 1, to 2, calories per day. For a man of pounds 70 kilograms , daily calorie needs can range from about 2, to 3, calories per day. In contrast, infants burn about 50 calories per pound of weight per day calories per kilogram. But the term "resting metabolic rate" is more common.
If you are looking to reach or maintain a healthy weight may find it helpful to calculate your BMR. You can either find the number using a formula designed by scientists, you can get it tested in a lab , or you can use an online calculator. No method is perfectly accurate, but a lab test will probably give you the best estimate. Put your height, weight, and age into our online calculator to find your basal metabolic rate with the addition of daily activity.
The calculator provides you with an estimate of the total number of calories you burn each day. Once you understand BMR and you get a good estimate of your number, you can use it to help you reach or maintain a healthy weight. First you can try to increase your basal metabolic rate, then you can increase the total number of calories you burn each day to help you reach your goal.
A combination of factors determines your basal metabolic rate. Genetic factors, age, gender and body composition all play a role. There's not much you can do to control genetics, age or gender. But you can change your body's fat to muscle ratio to boost your metabolism. So how do you change your body composition? Build muscle! Even when your body is at rest, lean muscle mass will burn more calories than fat.
And you don't even have to be a bodybuilder to see benefits. The total number of calories you burn each day is heavily dependent on your basal metabolic rate. But you can also burn more calories each day by making changes to your diet and activity level. Your basal metabolic rate combined with two other factors can give you an idea of the total number of calories you burn each day.
If you can burn more calories than you consume, you will create a calorie deficit or negative energy balance. A calorie deficit of calories per day should result in a pound weight loss per week. Learning about your basal metabolic rate and the total number of calories you burn each day is a positive step in the process of reaching or maintaining a healthy weight.
But this obscures many truths about this essential, yet still somewhat mysterious, biological process. Here are nine facts to help you understand metabolism, and how to think about it in the context of weight gain and weight loss. A lot of people talk about their metabolism like it's a muscle or organ that they can flex or somehow control.
But in reality, your metabolism refers to a series of chemical processes in each cell that turn the calories you eat into fuel to keep you alive, said Michael Jensen , a researcher who studies obesity and metabolism at the Mayo Clinic.
Your "basal" metabolic rate measures how many calories you burn while you're doing nothing, he added. The body's major organs — the brain, liver, kidneys, and heart — account for about half of the energy burned at rest, while fat, the digestive system, and especially the body's muscles account for the rest. There are three main ways your body burns energy each day: 1 the basal metabolism — energy used for your body's basic functioning while at rest; 2 the energy used to break down food also known as the thermic effect of food ; and 3 the energy used in physical activity.
As we explored in a feature , one very underappreciated fact about the body is that your resting metabolism accounts for a huge amount of the total calories you burn each day. Physical activity, on the other hand, accounts for a tiny part of your total energy expenditure — about 10 to 30 percent unless you're a professional athlete or have a highly physically demanding job. Digesting food accounts for about 10 percent.
It's true that two people with the same size and body composition can have different metabolic rates. One can consume a huge meal and gain no weight, while the other has to carefully count calories to not gain weight. Researchers have found some predictors of how fast a person's metabolism will be. These include: the amount of lean muscle and fat tissue in the body, age, and genetics though researchers don't know why some families have higher or lower metabolic rates.
Sex also matters, since women with any given body composition and age burn fewer calories than comparable men. You can't easily measure your resting metabolic rate in a precise way there are some commercially available tests, but the best measurements come from research studies that use expensive equipment like a metabolic chamber. But you can get a rough estimate of your resting metabolic rate by plugging some basic variables into online calculators like this one.
It'll tell you how many calories you're expected to burn each day, and if you eat that many and your weight stays the same, it's probably correct. The effect happens gradually , even if you have the same amount of fat and muscle tissue.
So when you're 60, you burn fewer calories at rest than when you're Jensen said this continual decline starts as young as age 18 — and why this happens is also another metabolism question researchers haven't answered.
There's a lot of hype around "speeding up your metabolism" and losing weight by exercising more to build muscle, eating different foods, or taking supplements.
But it's a metabolism myth. While there are certain foods — like coffee, chili, and other spices — that may speed the basal metabolic rate up just a little, the change is so negligible and short-lived, it would never have an impact on your waistline, said Jensen. Building more muscles, however, can be marginally more helpful. Here's why: One of the variables that affect your resting metabolic rate is the amount of lean muscle you have.
At any given weight, the more muscle on your body, and the less fat, the higher your metabolic rate. That's because muscle uses a lot more energy than fat while at rest see the graphic in section one. So the logic is if you can build up your muscle, and reduce your body fat, you'll have a higher resting metabolism and more quickly burn the fuel in your body. Jensen also noted that it's difficult for people to sustain the workouts required to keep the muscle mass they gained.
Overall, he said, "There's not any part of the resting metabolism that you have a huge amount of control over. The control tends to be relatively modest, and unfortunately, it also tends to be on the downside.
While it's extremely hard to speed the metabolic rate up, researchers have found there are things people do can slow it down — like drastic weight loss programs. For years, researchers have been documenting a phenomenon called "metabolic adaptation" or "adaptive thermogenesis": As people lose weight, their basal metabolic rate — the energy used for basic functioning when the body is at rest — actually slows down to a greater degree than would be expected from the weight loss.
To be clear: It makes sense that losing weight will slow down the metabolism a bit, since slimming down generally involves muscle loss, and the body is then smaller and doesn't have to work as hard every minute to keep running.
But the slowdown after weight loss, researchers have found, often appears to be substantially greater than makes sense for a person's new body size. In the newest scientific study to document this phenomenon, published in the journal Obesity , researchers at NIH followed up with contestants from season eight of the reality TV show The Biggest Loser.
By the end of the show, all of the participants had lost dozens of pounds, so they were the perfect study subjects to find out what happens when you lose a dramatic amount of weight in a short period of time. The researchers took a number of measurements — bodyweight, fat, metabolism, hormones — at both the end of the week competition in and again, six years later, in
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