Presidential Closing Remarks 12:05 PM – 12:15 PM: Immediately Following President's Lectures ROOM: Ballroom 2/3 and Ballroom 1: D-18 Free Communication/Slide – Weight Control II: THURSDAY, JUNE 1, 2006 1:00 PM – 3:00 PM ROOM: 401
The rising obesity epidemic is associated with an increasing prevalence of cardiometabolic disease. Plasma leptin levels are highly related to the degree of obesity and are influenced by dietary macronutrient content.
Combined effects of varying macronutrient composition and meal frequency on body composition and plasma leptin (LEP) are not well known.
PURPOSE: To compare the effects of consuming 3 vs. 6 meals/ day, with higher versus lower protein, on body composition and LEP.
METHODS: Twenty-seven healthy male and female subjects completed an eight week dietary intervention consisting of two four-week phases: a weight maintenance phase (Phase I, energy balance) followed by a weight loss phase (Phase II, 25% energy deficit). The two high-protein groups (40% protein, 40% carbohydrate, 20% fat) consumed either 6 meals (HP6) or 3 meals (HP3) per day. The third group consumed 3 meals/ day (AHA) in compliance with the American Heart Association (15% protein, 60% carbohydrate, 25% fat). Total and abdominal body fat (DXA), body water (BIS), and fasting LEP were assessed at baseline and end of Phase I, and Phase II.
RESULTS: Body weight remained stable in HP6 and HP3 but declined 0.8 kg in AHA (p = 0.04). Body weight significantly decreased in all groups from baseline to end of phase II (p<0.005). Body fat decreased significantly at end of Phase I in all groups (1.9 kg HP6, 2.0 kg AHA, 1.9 kg HP3; p<0.001), despite consumption of 100% of estimated energy needs (RMR, indirect calorimetry plus activity factor). Lean mass increased in HP6 by end of Phase I (45.7 vs. 46.6 kg; p = 0.05) and tended to remain higher at end of Phase II (46.3 kg, p = 0.06) and was unchanged in AHA and HP3. HP3 and AHA lost significant abdominal fat during Phase I (p<0.05) whereas HP6 lost significant abdominal fat (0.4 kg, p = 0.001) during Phase II. Total body water did not change in any of the groups during the eight week intervention (p = 0.22). LEP tended to increase in HP6 (13,565 vs. 17,975 pg/ml, p = 0.076) at the end of Phase I but decreased significantly during Phase II (17,975 vs. 10,842 pg/ml, p = 0.001). LEP concentrations were unchanged in AHA and HP3.
CONCLUSION: All diet interventions resulted in significant reductions in fat mass during Phase I (energy balance), however, HP6 experienced further reduction in total and abdominal fat mass during Phase II (energy deficit). LEP responded in a similar fashion in HP6 decreasing during phase II. These results indicate that increased meal frequency and increased dietary protein may have a beneficial effect on reducing of total and abdominal fat mass, which is associated with a reduced LEP.