Anyone who is overweight needs help – instead of BMI and other indices

Asterix and Obelix argued bitterly and entertainingly about who was actually too fat. Science has been debating this more seriously for decades. At what point does someone become so overweight (and so sick) that he or she needs treatment? Or to put it another way: At what point is excess weight no longer a cosmetic problem, but a medical one? A top-class expert commission has just tried to answer this and presented a new definition of obesity in the medical journal.

The key figures previously used by doctors to distinguish healthy from sick fat people are inaccurate. Above all, the well-known body mass index (BMI). Its advantage is that it is easy to calculate (body weight in kilos divided by the square of the height in meters) and provides at least a rough indication of who should lose weight for health reasons. Studies show that in many cases, slightly overweight people with a body mass index of over 25 do not become seriously ill. But especially from a BMI of 30, the limit for obesity, the risk of secondary diseases such as type 2 diabetes or heart disease increases significantly.

However, the index fails when it comes to other details: Even well-trained strength athletes can be considered overweight or even obese according to the BMI, because the index says nothing about how high a person’s fat and muscle mass percentage is. It also doesn’t say whether the body fat is harmless subcutaneous fat on the thighs or risky fat deep in the abdomen that is associated with chronic inflammation and diabetes. The BMI often does not recognize those who carry a high risk with them – or mistakenly defines perfectly healthy people as being at risk.

Therefore, the International Commission for Clinical Obesity, a committee of experts in which German scientists also work, is now recommending a new definition of overweight and obesity. In the future, in addition to the BMI, the waist circumference, which better captures abdominal fat, should also be taken into account. Or a direct body fat measurement from the doctor. In addition, other symptoms of the disease or critical blood values ​​should be looked for in order to distinguish those who need treatment from those who are “still healthy”.

The approach is a step in the right direction and could help to better identify sick or at-risk people. In practice, however, it will not change much for the time being: the medical obesity guidelines for adults are still based on BMI, but at least already take the measurement of abdominal and hip circumference into account.

Above all, however, no index, no matter how precise, solves the problem that in this country even obese people who are proven to be sick are sometimes left alone with their kilos. According to the World Health Organization, obesity is now considered an independent disease – but anyone who is obese in Germany does not automatically receive treatment.

Whether a health insurance company will pay for exercise therapy or nutritional advice, for example, must be applied for individually. Insurance doesn’t always pay. According to the Federal Social Court ruling of 2003, in the case of severe obesity, those with statutory health insurance are even entitled to certain operations such as a stomach reduction. However, unlike other therapies for seriously ill people, this too must be applied for and approved by the health insurance company in each individual case.

Weight-reducing drugs such as the “weight loss injection” with semaglutide are generally not reimbursable, even in cases of obesity – despite proven effectiveness and initial positive data on health benefits. Paragraph 34 of the Social Security Code V prohibits health insurance companies from covering the costs of “lifestyle” medications such as weight loss aids. This even applies to patients who participate in the recently launched Obesity Disease Management Program, a structured medical program designed to improve care.

In this respect, it is right for criteria and indices to be sharpened and improved. But if overweight people who are proven to be sick are often not treated, the problem lies more in the implementation of care in practice.