The team from the University of Newcastle upon Tyne studied 412 men and women from birth to adulthood and found that fatter adults were more likely to have increased insulin resistance, a risk marker for type 2 diabetes.
Childhood factors, such as birth weight and nutrition, were found to have limited impact, whereas they were previously thought to be significant, say the authors in Diabetes/Metabolism Research and Reviews (DOI: 10.1002/dmrr.573).
Diabetes is a global health problem that is presenting a major medical challenge worldwide. In the UK alone, diabetes has been said to account for 9 per cent of the annual National Health Service budget - approximately £5.2 billion a year.
Type 2 diabetes, in which the body's tissues become resistant to the insulin produced leaving too much glucose in the blood, is strongly related to overweight and lack of physical activity, and accounts for 90 per cent of all diabetes.
The World Health Organisation predicts that the number of people with type 2 diabetes will more than double over the next 25 years, linked to both the rise in ageing populations and the growing obesity problem.
The Newcastle study measured the percentage body fat and waist-hip ratio of the subjects, along with other lifestyle elements. Men and women with a higher body fat and higher waist-hip ratio were more likely to demonstrate increased insulin resistance.
Study leader Dr Mark Pearce said promotion of healthier lifestyles throughout life would be the public health intervention most likely to reduce insulin resistance in later life.
"Previous studies have suggested that risk of poor health in later life is programmed by impaired development in the womb, and that poor growth in foetal and infant life is associated with impaired insulin secretion and sensitivity. However, not all of these studies have had access to complete data on later life," he said.
"Our study, which has examined people from birth to adulthood, suggests that the life you lead as an adult has the biggest influence on your health, in terms of diabetes risk, in later life."
The data was collected as part of the Thousand Families Study, a Newcastle University project, which has examined the health of children born in Newcastle in May and June 1947 throughout their lives.
Dr Pearce added that despite the findings of limited impact from childhood, parents still have a role to play in introducing their children to eating a healthy diet so they can develop good habits throughout adulthood and old age.