Thin babies may have a higher risk of developing diabetes later in life, according to a study.
Low weight babies may be most at risk
Scientists say the problem seems to occur if they gain weight too quickly as they grow older.
Writing in the New England Journal of
Medicine, they urged doctors to monitor children's weight more carefully.
"It is the thin two-year-old not the fat one who faces the greater risk," said Professor David Barker of Southampton University.
The number of people being diagnosed with diabetes around the world has rocketed in recent years.
In the UK, an estimated two million people have the disease. Globally, the figure is 150 million. This is expected to rise to 200 million by the end of the decade.
One of the countries with the biggest problems is India. In 2000, almost 25 million Indians had been diagnosed with diabetes. That is predicted to rise to 40 million by 2010.
Scientists from the UK and India teamed up to carry out this latest study.
They traced nearly 1,500 residents of a community in South Delhi, who as children had taken part in a study looking at childhood growth more than 20 years ago.
The scientists found that more than 15% had high blood sugar levels, a major risk factor for diabetes. A further 4% had diabetes.
The scientists discovered that people with these conditions generally had low birth weights and remained thin during infancy.
However, after the age of two they all started to gain weight rapidly.
None was obese during childhood. However, their weight gain continued into adulthood and many became overweight or obese.
The later in life the child began to gain weight the lower their risk of developing diabetes.
The scientists said the findings may explain why India, in particular, is seeing a sharp rise in the disease.
In the past undernourished babies were born into poor families with limited access to food.
In recent years, the country and its people have become richer and many low weight babies are now born into families with a plentiful supply of food.
This problem is compounded by the fact that youngsters, like those in many other countries, are less active than previous generations causing them to gain weight more quickly.
Professor Barker said the findings may have global implications.
"This knowledge will be useful in fighting the diabetes epidemic worldwide, but it is particularly important in developing countries like India, where although diabetes is rapidly becoming a major health concern, public health messages still focus on reducing childhood 'under nutrition'.
"It should also help the UK understand why British Asians have such poor heart health."
Professor Jeremy Pearson, associate medical director at the British Heart Foundation, which funded the study, welcomed the research.
"This is a ground-breaking step forward in shackling the rising threat of diabetes in India and the rest of the world."