Although the II is not corrected for the threshold value of glycemia required to augment insulin release above the basal value, the present finding of a much higher plasma insulin/glucose ratio in obese than non-obese control subjects is consistent with the hypothesis that obesity, as caused by an imbalance between food intake and energy expenditure, eventually leads to a rise in insulin output and, possibly, even in the insulin secretory responsiveness of the endocrine pancreas to a given hexose concentration [42,45]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.