A study has found that the chances of an obese person achieving normal body weight are very low.
People are often advised to lose 5% to 10% body weight, but researchers the likelihood of achieving the target is just one in 12 for men and one in 10 for women.
Of those that did manage 5% weight loss, more than half (53%) regained it within two years and nearly four in five (78%) put it on again within five years.
The study, led by King's College London, found the chance of an obese person attaining normal body weight was just one in 210 for men and one in 124 for women, while it was just one in 1,290 for men and one in 677 for women with severe obesity.
The findings, published in the American Journal of Public Health, suggest that current weight-management programmes focused on dieting and exercise are failing to achieve sustained weight loss for the majority of obese patients.
Researchers tracked the weight of 279,000 men and women using UK health records from 2004 to 2014.
A minimum of three body mass index (BMI) records per patient was used to estimate weight changes and anyone who received bariatric surgery was excluded from the study.