Risk of death: Better too fat than too thin

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MunichA big belly is a health risk - doctors tirelessly warn against this. There is less public awareness that too little body mass can also be dangerous. The risk of premature death is even higher for underweight people than for obese people, shows a large survey study.

For this, researchers led by Joel Ray from St. Michael's Hospital in Toronto evaluated 51 studies that examined the relationship between BMI and deaths. The researchers only considered studies that ran over a period of more than five years largely weed out from the dataset those participants who were underweight due to cancer, chronic lung disease, or heart failure - which would have skewed the results.

Risky underweight

The result: Underweight people with a BMI of less than 18.5 had a 1.8 times higher risk of dying within the respective study period than people of normal weight (BMI between 18.5 and 24.9).

For obese people (BMI 30-34.9) the risk of death was only 1.2 times higher. Even those who were severely obese with a BMI of over 35 still had a significantly better chance of surviving the duration of the study than underweight participants (1.3 times the risk of death).

Dangerous slimming mania

Ray points out that social attention is currently focused heavily on the army of the overweight. It is true that this is actually a real problem: "But we have to make sure that we do not generate an underweight epidemic in return," says the scientist. Even people of normal weight could be influenced by the campaigns and the slim beauty models and ultimately lose so much weight that they seriously endanger their health. Being underweight is often associated with malnutrition, which can weaken the body. In addition, if an underweight person becomes seriously ill, he has hardly any reserves.

Waist circumference is the better yardstick

It is crucial to use the right measuring tools for assessing a healthy weight, says Ray. "The BMI not only measures body fat, but also muscle mass," explains the researcher. However, a balanced relationship between storage fat and muscles is important for health. The waist circumference is therefore more suitable than the BMI for assessing the health risks. Women should aim for a waist circumference of less than 88 centimeters, for men it should be less than 102 centimeters if possible. (cf)

Source: Sissi Cao et al .: J-shapedness: an often missed, often miscalculated relation: the example of weight and mortality. Journal of Epidemiology and Community Health, March 2014 DOI: 10.1136 / jech-2013-203439

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