Figure 1. Experimental protocols.

Each participant underwent three experimental protocols. The first protocol consisted, first, of a two-hour fasting experimental phase (time 0 to 120 min) followed by a two-hour normoglycemic hyperinsulinemic clamp (time 120 to 240 min) with determination of plasma glycerol and NEFA metabolism using stable isotopic tracers. The second protocol (postprandial or PP protocol) consisted in a 6-hour continuous oral intake of a standard liquid meal with determination of steady-state postprandial glycerol and NEFA metabolism using stable isotopic tracers. The third protocol (postprandial with exogenous insulin infusion or PP+INS protocol) was identical to the second protocol with the exception of intravenous insulin and dextrose infusion in the last 3 hours of the postprandial experiment to maintain normoglycemia (∼5.5 to 6.0 mmol/l) in all participants.