We have always believed these two things about basal metabolism and total metabolism.

• The first is men burn more calories to live, women less.
• The second is that these parameters vary with age, decreasing from the age of 40.

Right? No. Wrong.
The biggest scientific turnaround on metabolism appeared in a major study that debunked two myths we all believed.
Looking at nearly 6,500 people from 29 countries between the ages of 8 and 95, a team of researchers found that everything we believed about metabolism was false.

THE DISCOVERY ON METABOLISM THAT WILL LEAVE YOU STUCCO

In a research that starting from Duke University up to the universities of Japan, Germany, Norway and so on, a team of scientists and researchers led by Dr. Hermann Pontzer, analyzed the total and basal metabolism of 6421 subjects of all age, men and women.

They used a technique we have already talked about, that of doubly marked water (or water marked with heavy isotopes): a very precise measurement.

By total metabolism we mean the amount of energy burned according to a daily average that takes into account all factors, from routine to physical activity to digestion and hours of sleep. By basal , on the other hand, we mean the energy it takes to keep us alive only, net of any activity. Basal metabolism, or the energy that our body requires to survive, is our largest calorie expenditure, over 55%.

Men and women have the same metabolism

But, beware, the researchers did not notice any variation in total metabolism between the men and women in the study. As we have seen, men and women have the same metabolism.
And no one was expecting this news already.

And it doesn’t change until the age of sixty

The other shocking news is that from the age of 20 to 60, our metabolism does not change. Zero.
In the 40 years that characterize our adulthood it remains the same.
In fact, it peaks in infants, who are real metabolic lightning bolts: they burn 50% more than us adults.

Then the metabolism changes during the growth, reducing gradually (second phase) up to 20 years in which it stabilizes to that of an adult (third phase).
And it remains stable for 20 to 60 years.
Andropause, menopause, pregnancies? They have no effect.
So it is not true that metabolism starts to slow down after the age of 30 or 40 or 50.
Researchers have seen that it shrinks by 0.7 percent per year, but from age 60 onwards and up to age 95.
This means that a ninety-year-old has 20% less of the total metabolism he had at sixty if he lives the same life and has the same body.
So how do you explain the differences between men and women, or in the different stages of life?
The only parameter that varies is that of body composition.
These values ​​found by the researchers are net of fat mass.

Conclusions

Clearly, if I have more fat than lean mass compared to another person, I will eventually have a different basal metabolic rate than her. Also in one day this person and I will move in different environments and we will do different things, we will eat differently and so on: our total metabolism will change.
The results are interesting on a subjective level: if I always maintain a good body composition, ie the same levels of lean and fat mass, age is not a sentence and at 50 I burn the same calories as at 20.