Researchers conducted the study on mice, which were the human equivalent of 30-years-old. They were fed half the recommended amount of protein.
The dietary imbalance of protein resulted in the mice containing lower quality sperm and seminal fluid. Their offspring were also bigger and developed type 2 diabetes.
Not having enough protein affects the quality of DNA that is passed down to the child. The team from Nottingham University have yet to understand why this occurs.
While there have been many studies that have found how lifestyle factors impact quality of sperm, this is the first to show how a father's children are affected by it.
Study author Dr Adam Watkins, told the Daily Mail: "Our research using mice shows at the time of conception, the diet and well-being of the father influences the long-term growth and metabolic health of his offspring.
"Our study not only identifies what impact a poor paternal diet has on the health of his offspring but also starts to uncover how these effects are established."
Half of the genes that make up a child come from sperm, Professor Kevin Sinclair, who was also involved in the study, wants people to understand.
"During natural conception sperm deposited in the female reproductive tract are bathed in seminal plasma which can in itself influence pregnancy outcomes," Professor Sinclair told the Daily Mail.
Adding, "Our study shows that the composition of seminal plasma can be altered by father's diet, and that this can also influence offspring well-being."
Adults should make sure at least 20% of their calorie intake is from protein daily....