Children may be at increased risk of diabetes if their grandmothers had a poor diet while pregnant and breastfeeding, animal studies suggest.

Scientists found insulin resistance - which can lead to diabetes - may be programmed across two generations.

They showed grandchildren of rats denied proper nutrition during pregnancy were at greater risk of obesity and insulin resistance.

The University of Texas study is published by the Journal of Physiology.

But UK diabetes experts said much more research was needed before the link could be confirmed.

Previous research has suggested that a child may be at increased risk of diabetes if their mother's diet was poor during pregnancy and breastfeeding.

But the US team, who collaborated with researchers from Mexico, believe their work is the first to show the effect may be passed down the next generation too.

Researcher Professor Peter Nathanielsz said: "These new findings stretch the unwanted consequences of poor nutrition across generations.

"It offers us important clues about the origins of insulin resistance and type 2 diabetes."

The study showed that granddaughters were particularly vulnerable if their grandmothers' diet was not up to scratch during pregnancy. The effect seemed to be less pronounced for grandsons.

However, boys seemed to be more affected if their mothers failed to get sufficient nutrients when being breastfed.

Dr Nathanielsz said the results underlined just how important it was that women eat well during pregnancy, and in the first few moths after giving birth.

However, he said further research was needed to determine the precise mechanisms at play.

The global incidence of type 2 diabetes is projected to double to 300 million by 2025.

The disease is responsible for early death, painful and debilitating complications such as limb amputation and blindness.

Natasha Ede, Care Advisor at Diabetes UK, said, "This is interesting research. We already know that it is important for women to eat a healthy, balanced diet before conception and during and after pregnancy.

"However much more research needs to be done before we draw any firm conclusions about the direct effects of a poor diet during pregnancy and the links to diabetes."