At 55, how much lower is the metabolic rate than at 25? The answer was unexpected!

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20-60 years old, both men and women, the metabolic rate remained stable, and there was no additional increase in the metabolic rate per body weight even during pregnancy.

Usually everyone defaults to middle-aged fat because their metabolism slows down. After all, many middle-aged fat people have experienced adolescence when they can eat no matter how much they eat.

But a new study, published in the top academic journal Science, overturns this common sense.

Mid-life gain is not due to slow metabolism

Different from the previous understanding that adolescence and menopause are time nodes of metabolic rate changes, new research found that our metabolic rate has been stable from 20 to 60 years old, and There was no significant decrease after age 25 or 30.

The study found that the changes in daily energy consumption and metabolic rate of a person’s life can be divided into 4 stages:

Newborn – 1 year old, rapid growth period

The total energy consumption and basal energy consumption of newborns just born for 1 month are similar to adults, and then increase rapidly, reaching the peak at about 1 year old, and the metabolic rate per body weight is 50% higher than that of adults .

1-20 years old, slow regression period

Total energy expenditure and basal energy expenditure are still increasing due to the increase in lean body mass (the weight of other body components except fat, mainly muscles, bones and internal organs), but the unit body weight Metabolic rate begins to slow by 2.8% per year.

20-60 years, stable period

Metabolic rate remained stable for both men and women, and there was no additional increase in metabolic rate per body weight even during pregnancy.

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After age 60, the real decline period

Lean body mass and fat mass decreased, total energy expenditure and basal energy expenditure decreased, and the metabolic rate began to decrease at a real rate of 0.7% per year.

Total energy expenditure and basal energy expenditure in 4 phases after adjusting for the effects of lean body mass and fat mass. Image source: Reference [1]

Metabolic rate indication: I will never bear the “pot” of getting fat in middle age!

The real reason for getting fat in middle age?

Too little movement must be one of the big reasons!

This study did not record the subjects’ diet, but used accelerometers that accurately recorded all physical activity to comprehensively measure the activity of subjects of all ages. It was found that the middle-aged subjects not only had a significant decrease in the energy consumed by activity, but also decreased the total energy expenditure and the basic energy expenditure…

Observed total energy expenditure (TEE; red), basal energy expenditure (BEE; black), and activity energy expenditure (AEE; gray), correlated with age and lean body mass. Image source: Reference [1]

Don’t despair yet.

Think of the first study conclusion: the metabolic rate is relatively stable between the ages of 20 and 60.

According to the research model, if you can guarantee the same amount of activity as when you were young, then your total energy consumption and basic energy consumption will not decrease even in middle age. .

From reference[1]

It seems that people who want to avoid growing waistlines in middle age still need to move more!

My Apple Watch 7 just arrived last week, and I’m ready to help each other with my mom to start exercising regularly.

Is the study overinterpreted?

Although this study was published in a top academic journal, more professional readers may still have doubts about whether the research data is reliable and whether the conclusions are suitable for Chinese people. It is a new study that has been over-interpreted by the media.

After all, “metabolism slows down after puberty” has long been not only the common sense of ordinary people, but also the consensus of the academic community.

Old research methods are outdated

Indeed, the authoritative textbook in the field of nutrition, “Krause Nutritional Therapy (15th Edition, 2020)” on age and metabolism still states that the basal metabolic rate decreases every 10 years after puberty 1%-2%. [2]

However, when I studied nutrition in 2005, it was only after the age of 60 that the basal metabolism decreased.

Image from: Reference [2]

But it can also be seen that this conclusion comes from an earlier study (1973), which was relatively crude in terms of measurement and statistical methods compared to today. .

The Double Standard Water Method, which measures daily energy consumption like this study, was only used in the 1980s An energy metabolism measurement method that can accurately measure the total energy consumption of the human body in daily life and work, and is known as the gold standard for energy metabolism measurement. This method is safe for babies and pregnant women.

Alternatively, accelerometers for measuring physical activity are ideal measurements for large population studies.

Not to mention that researchers now have access to more precise statistical methods.

Large study sample and diverse population structure

Advanced research methods, especially the “double-labeled water method”, are expensive and therefore limited in scale and scope.

The researchers then built a huge database that, by sharing data, eventually expanded to 6421 in 29 countries. The subjects, ranging in age from 8 days after birth to 95 years old, achieved full coverage of men, women and children.

Therefore, this research conclusion is quite general.

A collaboration of researchers from multiple countries. Image from: Reference [1]

Although the paper does not explicitly state whether there are data from the Chinese population, considering that there are researchers from China, it is very likely that there are data from the Chinese population.

Research works, then what?

A new study reveals what the average person might be most concerned about with practical implications for their own lives.

Specifically, this research may have positive implications for our lives in two ways.

Particular attention should be paid to nutrition in children under 5 years of age

A key finding of this study is that infancy and early childhood are the most energy-intensive stages of life, not adolescence as previously thought.

Evolutionary biologist Professor Herman Pontzer, the first author of the paper, speculates that the metabolic rate of infants and young children is so fast that it is “like another species”, mainly because the brain, other organs at this stage And the developing immune system, especially the developing brain, is extremely energy-intensive.

Children maintain a relatively high metabolic rate until age 5. This means that children in this period are particularly susceptible to physical hazards such as growth retardation and disease if they are undernourished. [3]