Experts: It’s time to weigh the body mass index as a measure of obesity

Body mass index is an inadequate means of assessing obesity. That’s why other meters must be used instead of or alongside it, states a wide group of experts in an authoritative medical publication.

The justification is that the body mass index does not reliably tell about a person’s health and well-being. It can underestimate or overestimate a person’s obesity.

Researchers therefore suggest a significant change in the assessment of obesity Lancet Diabetes and Endocrinology in the journal. The 58 experts of the Lancet Commission are quite unanimous in rejecting thinking based on body mass index.

Body mass index (BMI in English) is calculated using a simple formula. Based on height and weight, the reading tells whether a person is underweight, normal weight, overweight or obese.

Body mass index however, it does not tell how much fat and muscle there really is in the body or where the pounds have settled in the body. The body mass index of a muscular person can claim that he is overweight. And it doesn’t tell about a person’s general state of health.

“The body mass index is still used as one of the factors when evaluating the initiation of obesity treatment. At the same time, we fully understand its difficulty. After all, we don’t want to make anyone overweight on purpose,” states the professor of clinical metabolism Kirsi Pietiläinen from the University of Helsinki.

According to the Lancet Commission, it would be better, for example, to directly determine the amount of body fat, if at all possible. To that, Pietiläinen replies that the clinics hardly use the method mentioned by the commission – so he is familiar with the statement.

Other measurements include waist measurement, waist-to-hip ratio, and waist-to-height ratio. Age and gender as well as ethnic background must also be taken into account, the summary of the report states.

Pietiläinen, however, found from his own information that body mass index can still work in determining obesity. It gave only one wrong determination when Pietiläinen compared the waist measurements and body mass indices of 500 patients.

According to the commission, the body mass index can still be practical if the person’s body mass index is over 40. This limit is exceeded, for example, if a person with a height of 170 centimeters weighs 120 kilograms, Pietiläinen mentions.

Report chairman of the Lancet commission, professor Francesco Rubino states that obesity needs to be defined more practically and precisely in terms of diagnosis and treatments.

“Some obese people have organs functioning normally and their health status is normal even for a long time, while some have signs and symptoms of a serious illness here and now,” says Rubino The Guardianissa.

The report suggests that obesity would be defined in two ways.

Clinical obesity is associated with signs or symptoms based on which the body’s function has weakened. The patient may have difficulties in everyday activities due to severe overweight. They should be offered appropriate treatments, such as drugs developed for weight control.

Milder pre-obesity would mean that the person’s body is functioning normally and he does not yet have obesity-related diseases. He still has the risk of progressing to clinical obesity and getting sick with, for example, type 2 diabetes, cardiovascular diseases and some cancers.

“New approach is an important opening, but it must not prevent treatment already in the pre-obesity situation. Those who receive such a definition may face risks of diseases in the future and may also want help to treat obesity themselves,” Pietiläinen reflects.

The fate of the body mass index must now also be weighed in Finland, because the Lancet commission’s report may cause confusion in the treatment of obesity.