The chances of an obese person achieving normal body weight are very low, a British study has found.
Losing five to 10 percent body weight is often recommended as a weight loss target. But researchers also found the chance of this being achieved was just one in 12 for men and one in 10 for women.
For those who did manage five percent weight loss, more than half (53 percent) regained it within two years and nearly four in five (78 percent) put it on again within five years.
The study, which was 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 1290 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 programs 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.
Overall, only 1283 men and 2245 women with a BMI of 30-35 (considered obese) reached their normal body weight. Those with a BMI above 40 were classed as severely obese.
"Weight cycling", with both increases and decreases in body weight, was also observed in more than a third of patients.