Married people are twice as likely to become obese than their single counterparts, according to a new study.

Greek researchers found that married couples were more likely to become fat due to their significantly changed lifestyle as they let themselves go.

The research, based on the study of more than 17,000 couples aged between 20 and 70, found that married couples exercised less frequently, had less sex, poor nutrition and were comfortable in their lives, reported telegraph.co.uk

Scientists from Salonica and Ioannina Universities, who presented their research to the Panhellenic Medical Conference, in Athens, concluded that abdominal obesity or belly fat was the worst problem among married people.

Prof Kiortsis, from Ioannina University who is also president of the Hellenic Medical Association for Obesity, said most married couples also have less sex, which is considered intense exercise that burns calories.

The study advised married couples to take up more exercise, to have only one home-cooked meal a day, to avoid snacks, and to follow a Mediterranean diet, which includes a lot of fruit, vegetables and olive oil.

Prof Dimitris Papazoglou, co-author from Salonica University, added: 'If one of the partners decides to go on a diet, then the other partner also often follows. Obesity is the biggest threat to public health in the entire world.'