Endurance training (study III) increased whole-body insulin sensitivity by 17–21% in the type 2 diabetes and obese groups (all p<0.01) and HIIT (study IV) increased whole-body insulin sensitivity by 29–42% in all groups (all p<0.001), whereas prior acute exercise did not change whole-body insulin sensitivity in individuals with obesity or in individuals with type 2 diabetes (study II). This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.