An obese man has only a one in 210 chance of ever achieving a normal weight again, while an obese woman has a one in 124 chance, a new study has found.

UK researchers tracked the weight of almost 280,000 people between 2004 and 2014. They assessed the probability of obese people reaching a normal body weight, or reducing their body weight by 5%.

Patients who received weight loss surgery were not included in the study and a minimum of three body mass index (BMI) records were used per patient to estimate changes in weight.

The study found that just 1,283 men and 2,245 women with a BMI of 30-35, which is classed as obese, achieved a normal body weight - this is equivalent to an annual probability of one in 210 for men and one in 124 for women.

Furthermore, if people are severely obese, i.e. they have a BMI of 40 or more, their odds of achieving a normal body weight fall even more - to one in 1,290 in men and one in 677 in women.

The study also found that the annual chance of an obese man losing 5% of his body weight was one in 12, while for women, it was one in 10. However, for those who managed to lose 5% of their body weight, 53% had regained this weight within two years, while 78% had regained it within five years.

The researchers from King's College London believe that the findings show that current attempts to reduce obesity rates are failing in most cases.

"Losing 5-10% of your body weight has been shown to have meaningful health benefits and is often recommended as a weight loss target. These findings highlight how difficult it is for people with obesity to achieve and maintain even small amounts of weight loss," commented the study's first author, Dr Alison Fildes.

She pointed out that 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. 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," she said.

Details of these findings are published in the American Journal of Public Health.

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