For mice at least, probiotic yoghurt could be the secret behind staying slim and 'sexy'.
Scientists at the Massachusetts Institute of Technology (MIT) in the USA came to this conclusion after a study to evaluate the effect of yoghurt on age-related weight gain.
The test subjects – 40 male and 40 female mice – surprised researchers Dr Eric Alm and Dr Susan Erdman when those who received yoghurt for dessert became not only considerably slimmer but seemed to have higher sex drives than their non-yoghurt-eating counterparts.
One group of mice were fed a high-fat, low-fibre, low-nutrient diet meant to mimic junk food. The other group received healthy mouse food. They then supplemented half of each diet group with vanilla-flavoured probiotic yogurt.
'One of the first things we noticed was their fur coat', Dr Erdman, assistant director of comparative medicine at MIT (Massachusetts Institute of Technology), told ABC News. 'It was so thick and shiny - shockingly shiny'.
And it was not just the fur and slimmer appearance that put the yoghurt-fed mice above the others; they seemed 'sexier' too.
'We knew there was something different in the males, but we weren't sure what it was at first', Erdman told ABC news. 'You know when someone's at the top of their game, and they carry themselves differently? Well, imagine that in a mouse'.
In fact, the testes of the mice eating healthy food and yoghurt were 15 percent higher than their junk-food eating peers, and five percent larger than for animals on a healthy diet but not fed yoghurt.
The final proof of the pudding was found when the yoghurt-fed mice inseminated their female cage-mates quicker. Meanwhile, the females benefitted from glossier fur and produced, in general, healthier offspring.
'It's the probiotics in the yogurt', Dr Alm told ABC News, adding that he believed 'the organisms are somehow directly interacting with the mice to produce these effects'.
Although the findings are as yet unpublished they may still have implications for human fertility. Scientific American spoke to Dr Jorge Chavarro, assistant professor of nutrition and epidemiology at Harvard University, who is investigating a potential link between yoghurt consumption and semen quality in men. 'So far our preliminary findings are consistent with what they see in the mice', he told the magazine.