A new study published in Diabetologia confirms the finding of an earlier study that shows that lean, young relatives of people with Type 2 diabetes already show dramatic differences in their ability to secrete insulin and their insulin sensitivity.
This points out very clearly that people who develop diabetes didn't cause their disorder by overeating, as they already have high post-meal blood sugars when young and thin. This is attributed in the study to beta cell dysfunction.
This study compared detailed measurements of insulin secretion and resistance in 187 offspring of people diagnosed with Type 2 diabetes against 509 controls. Subjects were matched with controls for age, gender and BMI. It concluded:
The first-degree offspring of type 2 diabetic patients show insulin resistance and beta cell dysfunction in response to oral glucose challenge. Beta cell impairment exists in insulin-sensitive offspring of patients with type 2 diabetes, suggesting beta cell dysfunction to be a major defect determining diabetes development in diabetic offspring.Beta cell (dys)function in non-diabetic offspring of diabetic patients M. Stadler et al. Diabetologia Volume 52, Number 11 / November, 2009, pp 2435-2444. doi 10.1007/s00125-009-1520-7