Men hooked on junk food could unwittingly be condemning their future children to diabetes, a new study has revealed.
Researchers warn that prospective dads should keep an eye on their diets in the same way as mothers-to-be, because health problems can be passed through subtle changes to DNA in sperm.
Britain is already fighting an epidemic of type 2 diabetes. Two million people are already diagnosed, with a further seven million on the borderline. And the figures are forecast to double by 2025.
Diabetes greatly raises the risk of heart disease, strokes, and conditions which can shorten lifespan by ten years.Much of the increase in diabetes in recent years has been blamed on expanding waistlines, but the study suggests that at least some of the seeds of destruction could be sown in previous generations.
Australian and American researchers fed young male rats a diet high in fat, mated them with healthy females and tracked the health of their female offspring. These 'daughters' developed diabetes before they reached puberty, with blood glucose concentrations double those of young born to other males.
The junk-food rats' daughters also produced half the amount of insulin, the hormone that regulates blood sugar levels and is key to the development of diabetes, reports the journal Nature.
Although the experiment included only female pups, it is thought that male offspring would be similarly affected.
It is thought the fatty food caused subtle changes to DNA in the rats' sperm, causing problems in the metabolism of the next generation.
Speaking in the New Scientist, Margaret Morris, of the University of New South Wales in Sydney, said: 'If similar effects apply in humans, it underlines the need for men to maintain a healthy diet and body weight.
'This is not only for their own health, but for that of the next generation.'
Dr Iain Frame, of British charity Diabetes UK, said translating the study to humans could help improve health outcomes in people at high risk of developing type 2 diabetes.
'We will watch this promising area of research closely,' he added.
Britons are the world's biggest junk food addicts, beating even the Americans. Almost half enjoy fast food too much to give it up, research shows.
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