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Healthy overweight people who lose weight die prematurely

A large group of overweight people are not ill because they weigh too much and for them, a diet can mean a shorter life. For these people stable weight and a healthy lifestyle should therefore be in focus rather than weight loss, explains an AU professor in the new report from Vidensråd for Forebyggelse (the knowledge council for prevention).

Overweight people typically suffer more diseases and die earlier than people of normal weight. But weight loss in itself is not a recipe for a longer and healthier life for everyone carrying a few extra kilos.

A large group of overweight people are actually not ill because they weigh too much and this group risks a shorter life if they lose weight.

This is the conclusion of a new report from the Vidensråd for Forebyggelse (the knowledge council for prevention), “Should overweight adults lose weight?".

The report identifies a 15 percent higher mortality rate among healthy overweight people who lose weight compared with healthy overweight people who maintain their weight.

Healthy lifestyle and a stable weight are important

”These new results stress the importance of preventing people from becoming overweight in the first place. But once a person is overweight and otherwise healthy, it is important that they do not gain more weight. The best thing this group can do to avoid weight gain is to be physically active and eat healthily instead of trying lots of diets to lose weight,” says the chairman of the working group behind the report, Professor Kim Overvad, Aarhus University.

So even though overweight is a major social problem, prevention is not just about focusing on BMI says the research group, which in addition to Kim Overvad includes Professor Annelli Sandbæk, Aarhus University, as well as researchers from the University of Copenhagen.

Move focus away from the bathroom scales

The researchers still do not know why weight loss apparently increases mortality among healthy overweight people. Possible explanations are the way in which the weight loss is achieved, how much weight a person has lost, and whether the weight loss is accompanied by fluctuations in weight.

For example, there is a risk that people who lose weight lose beneficial fatty tissue around the hips and thighs or muscle mass instead of losing the harmful fat around the waist. Finally, it is possible that weight loss frees up harmful substances which are deposited in the fatty tissue.

”But this new knowledge means that everyone who advises healthy overweight people ought to move their focus from the bathroom scales as the sole answer and look towards advice and guidance about physical activity and healthy diet,” says Kim Overvad.


Facts:

  • 54 percent of adult Danish males and 39 percent of women have a body mass index (BMI) of more than 25 (overweight). In addition, 14 percent of males and 13 percent of women have a body mass index (BMI) of more than 30 (obese).
  • Healthy overweight is defined as adults with a BMI between 25-30 who do not show signs of the metabolic syndrome or obesity-related complications such as cardiovascular disease and diabetes.
  • Overweight people who have both a BMI that is too high and a high waist measurement, or overweight people who have developed signs of illness, will probably still benefit from losing weight.
  • For obese people (with an average BMI ?30) without known health­ problems, mortality is not influenced by weight loss.

Further information

Professor of Epidemiology, Consultant, PhD Kim Overvad
Department of Public Health, Aarhus University
Direct tel: +45 4118 1287
ko@soci.au.dk

Professor of General Practice, MD, PhD Annelli Sandbæk
The Department of Public Health, Aarhus University
Direct tel: +45 2128 2073
annelli.sandbaek@alm.au.dk