An American study has concluded that men who eat foods that are high in saturated fat could be damaging their fertility.
Experts at Harvard Medical School discovered that men who consumed processed foods like bacon, sausages and ham, dairy and butter may have fewer sperm than those who ate healthier foods rich in omega 3 and omega 6.
Researcher, Dr Jill Attaman, said: "We were able to demonstrate that in men who took in higher amounts of fats, such as saturated fat and monounsaturated fat, there was an association with decreased sperm concentration.
"But polyunsaturated fat - those seen in fish primarily - was associated with improved sperm morphology and motility."
The research was carried out on 91 men seeking fertility treatment, but Dr Attaman said she would expect to see a "similar pattern" in the general population, although this would need to be studied.
The men were asked how often they ate certain foods, what types of oil they used in cooking and baking, and the types of margarine they consumed, while 21 of the group had levels of fatty acids in their sperm and semen measured.
Overall, the study concluded that men in the highest saturated fat intake group took 13% of their daily calories from eating foods high in saturated fat, as opposed to those in the lowest group who only took 8%.