People who are fat and fit live just as long as their slim counterparts and are less likely to die from heart disease, according to a new study.

Researchers looked at 6,000 obese Americans over a 16-year period and compared their death rates with those of lean individuals.

The findings were published today in the journal Applied Physiology, Nutrition And Metabolism.

Study leader Dr Jennifer Kuk, from York University in Toronto, Canada, said: "Our findings challenge the idea that all obese individuals need to lose weight.

"Moreover, it's possible that trying - and failing - to lose weight may be more detrimental than simply staying at an elevated body weight and engaging in a healthy lifestyle that includes physical activity and a balanced diet with plenty of fruits and vegetables."

Healthier obese people were generally heavier in early childhood, happier with carrying extra weight, and less likely to try to lose weight during their lives, said the researchers.

These individuals were also more likely to be physically active and to consume a healthy diet.