And those who have tied the knot were also likely to drink 'significantly' more wine, the study found.
Scientists were not sure why marriage made such a difference to men's attitude to their weight, but one suggestion was that they felt they could relax after their wedding day.
Another theory was that men who marry a good cook might find they are eating richer food than in the past.
Cakes, buns and other treats could also be in easy reach if they have a wife with a sweet tooth doing the shopping.
And the study even suggested that some wives deliberately overfeed their husbands, with the aim of making them less attractive to other women.
Tam Fry, an obesity expert who has been married for almost 50 years, said: "The problem is that men have done all the hard work.
"They've taken the woman out to dinner and made a fuss of her and all that stuff and now it's payback time.
"The woman looks after her husband and the man just sits back and gets fat."
Mr Fry, from the National Obesity Forum, went on to say: "I have to think of my own circumstances. My wife cooks for a small army and I have to be very careful how much I eat. The woman wants to please the man.
"You can get to a man through his stomach - but it's really up to the man to work out whether he wants to be a slob."
However despite all the dispiriting news for married men, the results of the study were not all bad. The team found married men ate more fruit and wholemeal bread than single ones.
And, unsurprisingly, those who have left their single days behind them got through fewer fatty kebabs and burgers. Researchers also discovered that men who were coupled up ate more yoghurt than men who had gone through a divorce, and that married men ate more chocolate than widowers.
Previous research has found that women also pile on the pounds after getting married.
US scientists tracked the lives of 10,000 people, and found that women had less time to exercise once they were married and were more likely to put on weight.
- Daily Mail
