Severe obesity is associated with an increased risk of various, sometimes fatal diseases. Bad omens for life expectancy. But this prognosis should be significantly improved by losing weight. At least that’s how the findings of a recent study on the subject of weight and mortality should be interpreted.
Researchers at the University School of Public Health in Boston (USA) wanted to find out how much weight affects life expectancy. Above all, it was about whether losing weight after becoming obese in early adulthood is associated with a reduction in mortality risk later in life.
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For this purpose, the scientists analyzed data from around 24,200 subjects. These were from the National Health and Nutrition Examination Survey database. It contains detailed health data for the US population.
course of the investigation
In order to understand to what extent – and in which phase of life in particular – weight affects life expectancy, the researchers examined different age groups. They defined the years from around the age of 40 as «midlife». Around the age of 25 they were in early adulthood.
An essential examination criterion was any changes in the body mass index (BMI)* within the previous ten years. Which of the subjects had lost or gained weight during the period mentioned, and if so, how much? In the next step, they compared the corresponding data with the mortality risk of the test subjects.
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(* The BMI is calculated from weight and height. The value is intended to indicate whether you are underweight, normal weight or overweight, and it should also allow the risk of various diseases to be assessed.)
Relationship between weight and life expectancy
Subjects who had lost weight between young adulthood and midlife were able to reduce their risk of death by 54 percent – and thus significantly. It was enough to lose so much weight that they could no longer be classified as obese according to the BMI, but «only» as overweight.
The life expectancy of the subjects who had not changed their BMI – i.e. maintained their weight – was correspondingly lower. There had been 5800 deaths in the illuminated period. Scientists estimate that a significant proportion of documented deaths could have been prevented by losing weight.
Important: The study looked at severely overweight subjects. The recommendation to reduce BMI is not aimed at people of normal weight. A BMI that is too low is just as unhealthy as a BMI that is too high. Being underweight can lead to various diseases.
Lose weight for a longer, healthier life
The study can currently be read in the web database Jama Network.
The results are also summarized in Medical News Today. Accordingly, they show «an important way to improve the health situation of the population,» according to study leader Prof. Andrew Stokes. It is particularly important at a young age to prevent or lose weight in order to reduce the risk of cardiovascular and metabolic diseases (e.g. high blood pressure and diabetes).