This observation will surprise more than one: Gaining a little weight over the course of life would be beneficial in terms of longevity, as long as the body mass index (BMI) remains within reasonable standards.

Weight gain as you age, especially when you are over 50, is a fairly classic phenomenon. Has human evolution wanted it so in order to give us an advantage in terms of life expectancy? In any case, the observation made by this American team (Ohio State University) should reassure seniors who are worried about having put on weight a little, as long as they do not exceed certain limits.

Very gradual weight gain

The data cover two generations: parents (recruited in 1948) and their children, followed for several decades, or until death. Their weight trajectory was recorded at periodic intervals and this information was crossed with the lifespan. A range of factors were taken into account, such as smoking, gender or socio-economic status.

What do we see? The premature death rate is lowest among those who have a healthy body mass index (BMI) at the age of 30, and who have very gradually gained weight in middle and old age, without being excessively overweight. Longevity is a little higher than in the group of those who have maintained a normal BMI (20 – 25) throughout life.

Watch out for obesity in young people

The lowest life expectancy is for people who are overweight or obese when they are young and who continue to gain weight: the higher the BMI initially and further increases, the greater the risk of premature death. This situation is particularly critical for the current generation, with an increasing incidence of childhood obesity.

In any case, while it is necessary to monitor your weight changes and intervene if necessary, the fact of putting on a few pounds over the years should not be a cause for disproportionate concern. In reality, and especially in the elderly, it is above all a sudden and unexplained weight loss that should cause concerns.