“I get fat because I have a metabolism that makes me assimilate everything, it does not make me burn anything, as soon as I eat something I assimilate it” are the many common phrases that we hear very often to justify weight gain. Now this belief seems to be out of date.
In fact, a study, whose lead author is Herman Pontzer, of Duke University (USA), processed data from 6,500 people aged between 8 days and 95 years. Metabolism, that is the set of chemical reactions that take place in the cells of the body to convert food into energy, is no longer the main cause of weight gain, but only a scapegoat.
In fact, the body loses the potential to burn calories as we age. In the article published in Science we read that this capacity increases in the first year of life, when the body needs to complete its systems, decreases until the age of 20, remains stable until the age of 60 and decreases from third Age.
In addition to these four fundamental periods of metabolism, the analysis confirms that there are no real differences between the metabolic rates of men and women under similar conditions.
The results indicate that total daily energy expenditure increases rapidly in infants and becomes double the average value for adults, however, after one year, it decreases to levels that remain stable between the ages of 20 and 60. And this also during pregnancy.
“From that age – Pontzer argues – it decreases until it reaches the lowest levels in the last years of life”.
These findings shed light on human development and aging and should help shape nutritional and health strategies throughout life.
Rozalyn Anderson, who studies aging as a professor of medicine at the University of Wisconsin-Madison, argues that “Metabolism is not just about energy, it’s about how the body handles nutritional fuel and turns it into energy currency. usable. Something that also includes the synthesis, modification and exchange of all aspects of cellular function. It is a sensor and a regulator. The energy demands of physical activity overlap with a widely integrated machinery “.
So there seem to be no more excuses for weight gain “When we weigh more it is simply because we eat more calories than we burn”.
In the case of children, the study reveals something not yet known and that is that in children the energy expenditure is higher, but their energy expenditure increases more than expected in relation to the size and characteristics of the body. “Something happens inside the baby’s cells that makes them more active and we still don’t know what the processes are,” says Pontzer.
According to Duke University, which supported the study, children’s metabolism may partly explain why children who don’t eat enough during that developmental period are less likely to survive and become healthy adults.
This accelerated metabolism of children decreases by an average of 3% each year until they reach the age of 20. Then it remains stable until the age of 60, even in conditions of pregnancy, when one might think that in that period there is a greater expenditure.
From 60 onwards our metabolism begins to lose power. From then on, he loses 0.7% of his energy every year, so a person over 60 needs 26% fewer calories than forty years ago.
The analysis of the American researcher concludes that “There are many physiological changes between growth and aging, from puberty, to menopause and other stages of life. The strange thing is that the calendar of the metabolic phases of our life does not seem to coincide with those fundamental stages ”.