Nearly 70% of US adults considered obese under proposed new definition, study finds

Nearly 70 per cent of American adults would be classified as having obesity under a newly proposed definition.

The traditional obesity measure, based on a body mass index (BMI) of 30 or higher, has long faced criticism for failing to distinguish between fat and muscle. In response, medical experts earlier this year called for an updated definition.

The new approach would label someone as being obese if they have a BMI over 40 or if they have a high BMI plus at least one sign of excess body fat, for example a large waist, high waist-to-hip ratio, or high waist-to-height ratio. People could also be classed as obese if they have two signs of excess fat even with a "normal" BMI, or if scans show they have excessive body fat.

Obesity would also be split into two categories: clinical, where the person also has health complications, and pre-clinical, where they do not.

Applying this definition to a nationally representative sample of more than 300,000 US adults aged 18 to 80, researchers found the prevalence of obesity jumped from 43 per cent under traditional BMI criteria to 69 per cent under the new system.

Among adults aged 70 and over, nearly eight in ten would be classified as obese.

The study, published in the journal JAMA Network Open, found that almost all people considered obese under the traditional definition also met the new criteria, with under 700 exceptions.

However, about 78,000 people who previously would not have been classed as obese were included in the new definition. Almost half would have clinical obesity.

Obesity in Europe

Overweight and obesity levels are also rising in Europe, according to a report by the European Food Information Council, a consumer-oriented non-profit organisation.

Using the traditional BMI measure for obesity, Romania (38 per cent), Malta and Hungary (36 per cent), and Croatia (35 per cent) have the highest rates for men in the European Union.

Meanwhile, obesity rates are lowest for men in France (10 per cent), the Netherlands (15 per cent) and Denmark (16 per cent).

The highest obesity rates among women were reported in Romania (32 per cent), Malta and Hungary (29 per cent each).

Among women, too, France is on the other side of the spectrum, at 10 per cent, ahead of Denmark (11 per cent), Austria, and Spain (13 per cent each).