The effect of meal replacements high in glycomacropeptide on weight loss and markers of cardiovascular disease risk

Background: Glycomacropeptide (GMP) is a peptide that has been shown to stimulate release of cholecystokinin, which may promote satiety. Objective: The aim of this one-year study was to examine whether greater weight loss could be achieved and sustained with a GMP-enriched whey powder supplement compared with a skim milk powder supplement. Design: In a double-blind, randomized, parallel-design study using meal replacements, weight, body composition (determined by dual-energy X-ray absorptiometry), blood pressure, fasting lipids, glucose, and insulin were measured at baseline, 6, and 12 mo. Meal replacements contained 15 g protein from GMP-enriched whey protein isolate (GMP-WPI) or skim milk powder (SMP) and 900 kJ/sachet. Volunteers consumed 2 sachets/d instead of 2 meals for 6 mo and 1 sachet/d for a further 6 mo. Of the 127 participants (95 women, 32 men, 95.5 +/- 15.4 kg, body mass index 33.4 +/- 3.4 kg/m(2) 50.0 +/- 12.4 y), 82 completed the 6-mo study and 72 of those completed the 12-mo study. Results: At 6 mo, weight loss was 9.5 +/- 5.8 kg compared with 11.0 +/- 6.0, GMP-WPI and SMP, respectively, and 9.9 +/- 8.8 kg compared with 10.8 +/- 7.4 GMP-WPI and SMP, respectively, at 12 mo (P < 0.001 compared with baseline, at both timepoints) with no differences between treatments. Total and LDL cholesterol, triacylglycerols, glucose, insulin, and systolic and diastolic blood pressure decreased at 6 and 12 mo (all P < 0.01 compared with baseline with no difference between treatments). HDL cholesterol increased at 12 mo (P < 0.001 compared with baseline). Conclusions: Meal replacements containing GMP had no additional effect on the overall sustained 12-mo weight loss of 10 kg. There were improvements in cardiovascular disease risk markers.