Generally divorce is considered bad for the health overall.

Women who get divorced late in life are slimmer and do more exercise than their married counterparts, a study shows.

Married women aged 50 to 79 were on average 2lb (about 1kg)heavier than those who had divorced.

The research suggests that being back on the dating scene later in life may mean women make more effort to lose weight.

Generally divorce is considered bad for the health overall and marriage has long-term health benefits.The new research does not change this, the scientists said.

But it seems when it comes to weight, married bliss leads to a bulging waistline, the study of 160 000 women found. The scientists say doctors should consider advising women who are getting married to make sure they stay physically active.

The research, published in the Journal of Women’s Health, suggested that married people eat larger portions than singletons.

Lead author Dr Randa Kutob, of the University of Atlanta’s College of Medicine, said: "Earlier studies have shown that marriage is usually associated with a longer lifespan and fewer health problems, while divorce is associated with higher mortality. With divorce in post-menopausal women, it’s not all negative, at least not in the short term."

The three-year project studied post-menopausal women in four groups – those who went from being single to married or cohabiting, those who were married but then separated or divorced, those who remained married and those who were single throughout.

All gained weight over the period, which is common in this age group. But those who went from unmarried to married put on most. Dr Kutob said the reasons were not entirely clear: "Potentially it’s portion size, because it doesn’t seem to be related to food choices."

Alcohol consumption was roughly equal and the study took emotional well-being into account.

Those who divorced had the most improved diets. Dr Kutob said: "It does seem that these women are consciously engaging in healthier behaviours after divorce. Some women take that moment to focus more on their own health."

However, the women were more likely to start smoking again after a divorce, the study found.