There’s a better way to define Obesity, the commission found

Commission on Obesity based on Objective Measurements of Disease: “We’re not throwing out the BMI”, says Dr. Robert Kushner

“Fat in the belly causes systemic inflammation, which then goes on and causes other metabolic problems like elevated blood sugar, elevated blood pressure and increased fats in the blood,” Kushner explains. This can make you vulnerable to diseases such as diabetes and heart disease.

In addition, the commission recommends two new categories of obesity, based on objective measures of illness. The first category is for people who have a chronic disease related to their weight. The second category is called ‘pre-clinical obesity’ and it means that the person has higher risks for developing a health condition due to their level of body fat.

“Our reframing acknowledges the nuanced reality of obesity and allows for personalised care,” says Dr. Francesco Rubino, of King’s College London, who is chair of the commission.

The Commission had 56 experts with expertise in nutrition, medicine, and public health. Their report is published in the Journal Lancet Diabetes & Endocrinology.

More than 1 billion people worldwide live with obesity, and the condition is linked to about 5 million deaths every year2 from disorders such as diabetes and cardiovascular disease.

The current BMI-based measure of obesity can both overestimate and underestimate how much body fat a person has, explains Dr. Robert Kushner, an endocrinologist at Northwestern University who is part of the Lancet Diabetes & Endocrinology Commission.

A group of 58 researchers are challenging the way that obese people are referred to, calling for a more nuanced approach to the problem despite the rise in the popularity of weight-loss drugs.

For people of European descent, obesity is typically defined by a BMI of 30 or higher, which correlates with a high level of body fat. A muscular athlete that is labelled obese on the basis of their body mass index should also be considered morbidly obese, because they have excess fat that increases their risk of cardiovascular problems or other health issues according to a leader of the group.

The commission recommends that excess body fat should be confirmed by measuring a person’s waist circumference, waist-to-hip ratio, or waist-to-height ratio. When this option is available and affordable, one can have a direct measurement of body fat from a screening.

“We’re not throwing out BMI, we are now recommending that individuals have another measurement obtained that more directly gets an estimate of body fat,” Kushner says.

The revised definition of adiposity, which was published in The Lancet Diabetes & Endocrinology1 on 14 January, focuses on how excess body fat, a measure called adiposity,affects the body instead of relying only on body mass index.

Robert Eckel, an Epidemiologist with the University of Colorado Anschutz Medical Campus in Aurora, says that the results of standard lab tests should be considered when determining if a person is obese. “These are objective diagnostic criteria, they’re standardized across global health systems,” he says.

Personalized assessments that consider age, gender and ethnicity are equally important, because certain groups might face health risks at lower BMI thresholds than others, says study co-author Louise Baur, a paediatrician at the University of Sydney, Australia.

“Now the idea is, eat less, move more, and you’ll lose weight,” says van Rossum, who wasn’t involved in the work. She says a healthy lifestyle isn’t important, and that this paper is an excellent way to discuss the complexity of Obesity.

This shift could improve clinical care, public-health policies and societal attitudes toward obesity, says Elisabeth van Rossum, an endocrinologist at the Erasmus University Medical Center Rotterdam in the Netherlands.