St?©phanie Bayol and Neil Stickland at the Royal Veterinary College, London fed female rats a "junk food" diet of crisps, cheese, muffins and other processed foods throughout pregnancy and lactation.

The offspring, who were overweight at birth, were born with a taste for junk-food themselves. But even when fed a healthy diet, the junk-food babies had a host of medical problems that lasted beyond adolescence into adulthood.

The rats had raised cholesterol and triglyceride levels - both associated with heart disease. Insulin and glucose in the blood were also unusually high, known to be a cause of type-2 diabetes. And the rats remained significantly podgier than normal with extra fat around the kidneys, another diabetes risk-factor.

The female offspring were particularly badly affected, expressing high levels of glucose and the appetite-promoting hormone leptin making them very prone to obesity.

"It seems that a mother's diet whilst pregnant and breastfeeding is very important for the long term health of her child," says Dr Bayol. "This does not mean that obesity and poor health is inevitable and it is important that we take care of ourselves and live a healthy lifestyle. But it does mean that mothers must eat responsibly whilst pregnant."

But will these results translate to humans? Very probably, says Professor Stickland. "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 says. "Our research certainly tallies with epidemiological studies linking children's weight to that of their parents."

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A particular concern was fat which was collecting around the major organs, which has been implicated in the development of type II diabetes and the rats with unhealthy mothers were more likely to have this, even if they were weaned off the junk food diet.

Interesting differences between the sexes were seen, 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.

The researchers say though the study was carried out in rats, the findings have implications for humans.

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 but now it seems even when weaned off this diet themselves, the damage may already have been done.

Researcher Dr. Stephanie Bayol, says it appears that a mother's diet whilst pregnant and breastfeeding is very important for the long-term health of her child.