Action Points

Fewer than 1% of obese people will attain normal weight, a new study suggests.

Those chances are about 1 in 210 for obese men and 1 in 124 for obese women, highlighting the need for better ways to prevent obesity, say authors of the cohort study, published in the American Journal of Public Healthon July 16.

And the news is even worse for those who are extremely obese: for them the chances of bringing BMI values into the normal range are 1 in 1,290 for men, and 1 in 677 women.

But chances of achieving clinically significant weight loss, at least 5% of body weight, in the morbidly obese were somewhat better although still low: 1 in 8 for men and 1 in 7 for women.

The study, conducted by Alison Fildes, PhD, at King's College in London, and colleagues, involved data from more than 75,000 men and nearly 100,000 women who hadn't undergone bariatric surgery and who were followed for up to 9.9 years.

"Our findings indicate that current nonsurgical obesity treatment strategies are failing to achieve sustained weight loss for the majority of obese patients," wrote Fildes and colleagues. "These findings raise questions concerning whether current obesity treatment frameworks, grounded in weight management programs accessed through primary care, may be expected to achieve clinically relevant and sustained reductions in BMI for the vast majority of obese patients and whether they could be expected to do so in the future."

Fildes and colleagues used data from the electronic health records of family practices in the United Kingdom via the Clinical Practice Research Datalink, which contains more than 7% of the country's population. All of those included in the study were 20 years or older and had records from 2004 to 2014.

The study was part of a larger analysis of how bariatric surgery is used, according to the authors. They estimated body weight changes independent of bariatric surgery, so participants who had undergone the surgery were excluded. Extreme or morbid obesity was defined as having a body mass index (BMI) of 40 to 44.9 kg/m².

The authors didn't originally include the chance of losing a clinically significant amount of weight, but added it later, they said. All patients had at least three BMI measurements by which to estimate weight change.

The proportion of participants that showed no change was greatest for the normal weight category (57% of men and 59% of women); it decreased as baseline BMI increased, with the exception of the super-obese with a BMI over 45 kg/m². Only 14% of men and 15% of women showed a decrease in a BMI category without also showing an increase in the same period.

Of those who did achieve 5% weight loss, 53% regained the weight within 2 years and 78% had regained it within 5 years, according to the study. Probability of achieving the weight loss increased as BMI categories increased. For both men and women, 12% recorded only BMI increases.

"The lack of sustained BMI reductions could be driven by low intervention uptake rates or their lack of effectiveness," wrote Fildes and colleagues.

Limitations of the study included the possibility of bias and error with weight recordings on electronic health records. And general practices in the U.K. have contractual financial incentives to provide a register of patients with a BMI of more than 30, which may have led to doctors more frequently recording a higher BMI.

In addition, because of the high levels of comorbidity seen in obese people, it's possible that they consulted more often with a doctor -- and had their BMI recorded more often -- than those in the normal weight group. And the authors added that it's possible that all of the patients in the study represent a biased, less healthy sample.

"If this is the case, then unintentional weight loss, along with comorbidities contributing to weight gain such as mobility impairment, may have influenced BMI changes disproportionately in our sample," the authors wrote.

The research was supported by the UK National Institutes for Health Research Health Services and Delivery Research program.

Researchers did not disclose any relationships with industry.

• Reviewed by F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine

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