Research from van Heemst et al. makes clear that offspring of familiar long-lived people have better glucose-handling than their partners from the general population and less prevalence of diabetes mellitus type 2. They do not differ in body composition, weight and cholesterol levels and do not eat less than their partners. Levels of Insulin-like Growth Factor 1 (IGF1) are not different, contrasting with high expectations of IGF1 based on studies in model organisms. Children of long-lived people seem to differ in the metabolic pathway of insulin, which may give a clue to the question why people differ in healthy life span. Studies go on to identify the level (liver, muscle, intestine, fat and/or brain) at which glucose clearance and insulin-sensitivity differ between offspring and partners.