"Oops, now as soon as I am 30 years old, my metabolic ability has declined, unlike when I was 20 years old, I didn't get fat no matter how I ate."
Everyone should have heard this sentence.
But does metabolic capacity really decline after the age of 30?
A recent study published in Science shows that our metabolism doesn't really start to decline until after the age of 60. The study found that metabolic capacity was stable between the ages of 20 and 60 after adjusting for fat-free mass factors, and even during pregnancy, pregnant women's calorie needs were the same as before pregnancy.
DOI: 10.1126/science.abe5017
In the study, the researchers used a large, diverse database of data from a large cohort from birth to old age, with a total of more than 6,400 people spread across 29 countries around the world. The researchers analyzed the daily energy expenditure of participants from 8 days to 95 years old, studying the effects of age and sex on total expenditure (TEE). Total daily energy expenditure reflects daily energy needs and is a key variable in human health and physiology.
The researchers used the "doubly labeled water" method to calculate participants' total daily energy expenditure, a "double-standard water" method that is a urine test that is considered the gold standard for measuring daily energy expenditure in everyday life.
Surprisingly, contrary to what we previously understood, metabolic capacity peaked not in their 20s, but in infancy. Our metabolic capacity at the age of 1 is 50% higher than that of adults!
Based on their metabolic capacity, the researchers divided their lives into four distinct life stages.
The first stage is newborns under 1 year of age,
The second stage is for adolescents between the ages of 1 and 20,
The third stage is adulthood (20 to 60 years),
Stage 4 is after the age of 60.
In the first stage (0-1 years), the energy expenditure of newborns in the first month after birth was similar to that of adults, with adjusted total energy expenditure (TEE) and basal expenditure (BEE) of 99.0 ± 17.2% and 78.1±15.0%, respectively, these two indicators increased rapidly in the first year of life, and at 1 year, the metabolic capacity was 50% higher than that of adults.
The high metabolic capacity of babies is understandable, and if babies do not get enough food, they are unlikely to survive or grow up healthy.
In the second stage of adolescence (1-20 years), after the initial surge in metabolic capacity in infancy, metabolism declines by about 3% per year until the 20s. The data showed that total energy expenditure fell from 147.8 ± 22.6% for 1 to 2 years old to 102.7 ± 18.1% for 20 to 25 years old, after which it stabilized at the adult level (20-60 years).
Although adolescence is the peak of growth, and one would expect total energy expenditure to be high during this period, the researchers did not see any increase in daily calorie requirements during adolescence after taking into account body size. "We really thought puberty would be different, but it wasn't," the study authors say.
In the third stage of middle age (20-60 years old), the results of the study are again surprising. Many of us think our metabolic capacity will decline year on year after age 30, but researchers have found that between the ages of 20 and 60, our energy expenditure is the most stable, and even during pregnancy, women's calorie needs are no more or less than expected.
In the fourth stage, after the age of 60, the metabolism began to decline year by year, falling by 0.7% per year. A person in his 90s needs 26 percent fewer calories per day than a middle-aged person.
After looking at these results, are you still blaming middle-aged people on the decline in metabolic capacity? The biggest reason for the happiness of middle-aged people may be to eat more and exercise less.
Written by | Jessica
Edit | Jessica