Why Your Teenagers Gain Weight?
Teenagers spend less calories at rest, which can lead to overweight if their diet is unbalanced.
According to a study published in the journal International Journal of Obesity, young people spend less calories at rest during adolescence. A result of human evolution that poses problems in a society of abundance.
At rest, the body spends energy to allow proper functioning of the brain, heart, liver, kidneys, and maintaining its body temperature: this is the basic metabolism. As adolescence is a period of rapid growth, which should logically require more calories.
But, this is not really what was found in this study by the University of Exeter (Great Britain) which lasted a dozen years between 2000 and 2012. 279 children were followed every 6 months between 5 and 16 years. Researchers were surprised to find that the calories burned at rest dropped to puberty: at 15 years, the energy used at rest would be 25% lower than that required at 10 years, which represents a decrease of 500 calories per day. This is the equivalent of one hour of a significant exercise each day. In the children studied, energy expenditure increased after five years, but decreased after 10 years during puberty.
Younger people did not seem to be doing more sports in their teens. Indeed, at puberty there was also a significant decrease in physical activity, especially among girls, which could increase weight gain: the level of activity of girls decreased by one third between 7 and 16 years.
In adolescence, the requirements are 1,600 calories per day. It was not until around the age of 16 that the amount of calories burned at rest began rising again. To explain this phenomenon, one hypothesis is that it is a means selected by evolution to conserve calories for changes that take place at puberty. But today, in a society of abundant food, this represents a risk of increasing obesity.
These results could explain why many teenagers gain weight at this time of their lives. Parents must therefore remain vigilant to prevent their teenagers from growing too much.
Mostazir M, Jeffery A, Hosking J, Metcalf B, Voss L, Wilkin T. Evidence for energy conservation during pubertal growth A 10-year longitudinal study (EarlyBird 71). Int J Obes (Lond). 2016 Sep 8. doi: 10.1038 / ijo.2016.158