Moving in with a boyfriend causes women to eat more unhealthily and put on weight.

But the opposite is true for men, whose long-term health benefits when they move in with a female partner.

Dieticians at Newcastle University said both partners try to please one another, and so change their dietary habits to suit their other half.

It leads men to eat more light meals, such as salads, fruit and vegetables, while women chose to make creamier, heavier dishes like curry or rich pasta sauces, which may please their partner.

Women still have the strongest long-term influence over the couple's diet and lifestyle, as they still have the traditional role of shopper and cook in most households.

The report, by Newcastle University's Human Nutrition Research Centre, reviewed the findings of a variety of research projects from the UK, North America and Australia, which looked at the eating and lifestyle habits of cohabiting couples and married couples.