Most people who are obese are highly unlikely to ever return to a normal weight, according to a new study. There is a 1-in-210 chance for an obese man to have a healthy body weight while women have a 1-in-124 chance, according to a study by scientists at King's College London.

For people diagnosed with severe obesity, the prognosis is even worse -- the chance for men to regain normal weight is only 1-in-1290, and for women, 1-in-677. Health officials warn that obesity is a serious global public health epidemic, and figures from the World Health Organization show that the disease has more than doubled since 1980 and that almost 40 percent of adults measured were obese in 2014.

The study, published in the American Journal of Public Health, suggests that current public health attempts to fix obesity are failing to show results.

"Once an adult becomes obese, it is very unlikely that they will return to a healthy body weight. New approaches are urgently needed to deal with this issue," first author Alison Fildes said, in a press release. "Obesity treatments should focus on preventing overweight and obese patients gaining further weight, while also helping those that do lose weight to keep it off. More importantly, priority needs to be placed on preventing weight gain in the first place."

The researchers tracked the weight of 279,000 men and women through British health records between 2004 and 2014. They used three or more measurements of their body mass index (BMI) to track their weight changes. Patients who underwent bariatric surgery or other weight-altering procedures were excluded from the study.

They found that men only had a 1-in-12 chance of losing 5 percent of their weight, while women had a 1-in-10 chance. Keeping the weight off was even harder, with over 50 percent of subjects regaining lost weight within five years, and a third of all patients showing fluctuating weight.

"Losing 5 to 10 percent of your body weight has been shown to have meaningful health benefits and is often recommended as a weight loss target," Fildes said. "These findings highlight how difficult it is for people with obesity to achieve and maintain even small amounts of weight loss."

The study said that most people in the U.K. attempt to tackle obesity by getting a referral from their general physician to a weight management program that typically focused on calorie reduction and exercise.

However, co-author Martin Guilliford said that the study emphasized the need to focus on preventing obesity. "Current strategies to tackle obesity, which mainly focus on cutting calories and boosting physical activity, are failing to help the majority of obese patients to shed weight and maintain that weight loss. The greatest opportunity for stemming the current obesity epidemic is in wider-reaching public health policies to prevent obesity in the population."