Eating a poor diet when pregnant or breastfeeding may cause long-lasting health damage to the child, animal studies suggest.

The offspring of rats fed fatty, processed food had high levels of fat in their bloodstream and around major organs even after adolescence.

The animals had a raised diabetes risk - even if they ate healthily.

The study, by the Royal Veterinary College and London's Wellcome Trust, features in The Journal of Physiology.

Studies by the same team have already shown that rats whose mothers were fed junk food during pregnancy and breastfeeding were more likely to crave similar snacks themselves.

However, the new twist is that even when weaned off this diet themselves, the damage may already have been done, they suggest.

Dr Stephanie Bayol, one of the researchers, said: "It seems that a mother's diet whilst pregnant and breastfeeding is very important for the long-term health of her child.

"We always say: 'You are what you eat', but in fact it may also be true that you are what your mother ate."

Of particular concern was fat gathering around the major organs, which has been implicated in the development of type II diabetes.

The rats with unhealthy mothers were more likely to have this, even if they were weaned off the junk food diet.

However, there were interesting differences between the sexes, with the male offspring of unhealthy mothers having higher levels of insulin and normal blood sugar, while the reverse was true of females, who also tended to be fatter.

Professor Neil Stickland, another of the researchers, said that there was no reason why the same principles should not apply to humans.

"Humans share a number of fundamental biological systems with rats, so there is good reason to assume the effects we see in rats may be repeated in humans."

He said that studies in humans had found links between the weight of parents and the weight of their children.

Early influence

Dr Pat Goodwin, from the Wellcome Trust, said that the study supported the growing evidence that there were many different risk factors which could contribute to someone becoming overweight.

She said: "Pregnancy can be a difficult time for many mothers, but it is important that they are aware that what they eat may affect their offspring."

However, Dr Simon Langley-Evans, a nutrition researcher from the University of Nottingham, said that the study did not prove that a mother's diet could affect the health of offspring beyond the effect on cravings and appetite.

He said: "I'm not convinced they have shown this - everything you are seeing here could be the result of obesity caused by increased appetite. "What it does show is that this early influence from the mother is very important."

Source: BBC