[Mise à jour du 17/08/2021]
There is a time in life when you can eat whatever you want without gaining weight or almost. However, the metabolism, that is, the rate at which we burn calories, would peak much sooner, and decline much later than we think. At least that’s what a scientific study published on August 13, 2021 suggests in the journal Science.
The researchers here analyzed the average number of calories burned by more than 6,600 people, in 29 different countries, during their lifetime. The ages of the participants ranged from just a week to 95 years old.
“As we age, there are a lot of physiological changes that take place in phases of our life such as puberty and menopause. What’s strange is that the timing of our ‘metabolic life stages’ doesn’t seem to match the markers we associate with growth and aging.”, Said study co-author Jennifer Rood, in a communicated.
“Some people think their teens and 20s are the age at which their calorie burning potential peaks.”Said Dr Peter Katzmarzyk, also co-author of the study. “Corn [celle-ci] shows that infants [ont] the highest metabolic rates of all“, he added. Energy needs increase during the first 12 months of life, so by their first birthday, babies burn calories 50% faster than adults in proportion to their height.
After the significant growth of early childhood, an individual’s metabolism slows down by about 3% each year until their twenties, when it stabilizes. And this until the fifties, even in the presence of pregnancies. According to the study data, our metabolism does not really start to decline until after age 60. The slowdown is very gradual, only 0.7% per year. But a 90-year-old would need 26% fewer calories each day than someone in their 40s. Part of the blame is the loss of muscle mass, since muscle burns more calories than fat.
5 things to know about metabolism
Responsible for our mood, the speed of aging, and our physical form, metabolism remains however unknown. Thanks to the work of researchers, we can better understand how this process that determines our energy consumption works.
Metabolism is a complex system. He determines how quickly and efficiently the body burns calories and how many calories we can eat in a day without gaining weight. Scientists continue to gain new knowledge about the factors that influence it. Because a healthy metabolism improves mood, slows down the effects of aging and maybe even sheds extra pounds.
A well-honed system
Although many of us talk about “metabolism” as if it is a unique bodily process, there are three types, whose everyone expends energy at a different rate. Metabolic rate at rest determines how much energy organs use to stay functional when we are just sitting down. It constitutes the largest share of metabolic energy expenditure during a normal working day with minimal activity.
Lean people don’t have faster resting metabolic rates. The metabolism active, which accounts for about 10 to 15% of calories burned each day, regulates the energy that is used while exercising. Finally, there is the thermogenesis food-induced energy, which is the energy the body uses to consume and digest food. Spicy foods and green tea may stimulate her slightly.
Muscle burns more calories than fat, recalls site Health. And since we lose muscle with agewe also lose our ability to burn calories. At 70, your resting metabolism may be 15% slower than it was in your 20s. That’s 15% less food than you can eat without gaining weight.
While building new muscle can help counter this tendency, it is even more important to use the muscles we already have. Whenever we do strength training, the muscles work, repair and reshape even after we finish exercising. By practicing sport regularly, we therefore increase the speed of the resting metabolism.
The body needs amino acids, the building blocks of protein, to function. If the diet does not provide enough, it will draw some from the muscles. Result: the metabolism at rest pays the price. Make sure add protein to every meal, not to mention breakfast.
The influence of regimes
Any weight loss diet slows down the metabolism. Indeed, when we lose weight, we lose fat and muscle, but if we take it back, we only regain fat. The part of the brain that handles metabolism is not interested in the aesthetic shape of a body, but by the energy it needs to survive. If you deprive your body of the calories it has learned to rely on, it will start to deprive muscles of fuel and to direct this energy to vital organs, causing a drop in metabolism.
To lose weight it is important to move smoothly. Start by losing about 10% of your body weight, maintain that weight for three to six months, and then lose more if desired.
Go to bed
A single night of sleep deprivation can alter metabolism and trigger weight gain. Because it is during this phase of rest that the body repairs itself and burns calories. To avoid slowing down the metabolism, it is therefore essential not to lack sleep.