Scientists have discovered a reason why small babies appear to be at heightened risk of developing type 2 diabetes later in life.
Prenatal under-nourishment can lead to problems later in life
They found a lack of nutrients in the womb permanently damages key cells in the pancreas which secrete insulin.
Low levels of this hormone mean the body cannot control blood sugar levels - raising the risk of diabetes.
The study carried out on mice by the Joslin Diabetes Center in Boston is published in the journal Diabetes.
Lead researcher Dr Mary-Elizabeth Patti said: "The bottom line is that if you don't have delivery of enough nutrients from the mother to the baby, the baby's pancreatic cells will be programmed abnormally."
Dr Patti said the effect would not show up until later in life - probably not until adolescence or even adulthood.
The researchers compared the offspring of mice fed a normal diet with those who were under-nourished for the final third of their pregnancy.
At birth, the babies of the under-nourished group weighed 23% less.
Tests showed that for the first two months of their lives all the baby mice had similar blood sugar levels.
But by four months those in the under-nourished group starting recording higher levels, and by six months they showed levels equivalent to full-blown diabetes in humans.
The researchers found no difference in pancreas size or numbers of insulin-producing cells.
But the cells were unable to step up secretion of insulin in response to a surge in blood sugar levels.
The problem seemed to be permanent, and persisted even when the animals' achieved a normal bodyweight.
Dr Patti said: "People and their doctors need to understand that prenatal under-nourishment makes a person permanently at higher risk for developing diabetes, so prenatal care is important.
"Moreover, if someone was born with low weight, they need to pay special attention to prevention tactics, including exercise and weight control to minimize insulin resistance - the other major factor involved in triggering type 2 diabetes.
"In particular, someone who was a low birth weight baby can compound the risk of developing diabetes by becoming overweight.
"The stage is set in two ways: low insulin production coupled with resistance to insulin - a double whammy."
Roopinder Brar, of the charity Diabetes UK, said the association between low birth weight and an increased risk of type 2 diabetes was well documented.
"This study on mice offers potential reasons behind this link. Although interesting, further research is needed before any definitive conclusions can be made."
Inadequate nutrition of a developing baby is not always simply down to the mother eating a poor diet.
It can be caused by abnormal development of the placenta and its blood vessels, or by high blood pressure, which damages the vessels.