Women who conceive while dieting put their child at risk of obesity or diabetes in later life, UK scientists suggested.
Researchers from the University of Manchester in northern England came to the conclusion after studying sheep -- and said the results could also apply to humans.
Ewes that received less food around the time they became pregnant produced lambs with an altered DNA structure in the region of the brain related to food intake and glucose levels, the researchers found.
Professor Anne White, who led the study, said the team's findings suggested that dieting around the time a baby is conceived may increase the chance of the child becoming obese later in life.
"This is not an inherited change in the genes but a change in the structure of the DNA that affects the genes, and therefore much more unusual," White said. "What is significant is that the changes we have found are in genes that control food intake and glucose levels and alterations in these genes may lead to obesity and diabetes."
The research, carried out with colleagues in New Zealand and Canada, was published in the Journal of the Federation of American Societies for Experimental Biology.
The team believes that although the study was conducted on sheep, the findings are also relevant to humans as they reveal a non-genetic or "epigenetic" way in which the DNA of offspring can be altered -- and could be important for disease prevention regimes.
White added, "Our study is important because it shows that factors in the brain can be altered by non-hereditary mechanisms and this results in changes in the body, which could make people obese."
It was announced Monday in a separate study that obese expectant mothers in the UK be given an anti-diabetes drug during pregnancy as part of a new trial that hopes to prevent their babies from being born overweight.