Gene set enrichment revealed a highly significant general trend following the difference in insulin sensitivity (measured by the rate of glucose disappearance –Rd- using a stable isotope – [6,6-2H2]glucose – during a hyperinsulinemic-euglycemic clamp; Perreault et al., 2018), where TCA cycle and respiratory electron transport and complex I biogenesis were enriched as follows: athletes > lean > obese > T2D (Source data 10). The gene discussed is INS; the disease is type 2 diabetes mellitus.