Nil Whey Protein Effect on Glycemic Control after Intense Mixed-Mode Training in Type 2 Diabetes.

ABSTRACT

Although intense endurance and resistance exercise training and whey protein supplementation have both been shown to independently improve glycemic control, no known studies have examined the effect of high-intensity mixed-mode interval training (MMIT) and whey supplementation in adults with Type 2 diabetes (T2D). PURPOSE: This study aimed to determine if peritraining whey protein supplementation combined with MMIT can improve glycemic control. METHODS: In a double-blind, randomized, placebo-controlled trial, 24 men (55.7 ± 5.6 yr) with T2D performed MMIT with whey (20 g) or placebo control for 10 wk. Glycemic control was assessed via glucose disposal rate during a euglycemic insulin clamp, fasting blood glucose concentration, and homeostatic model assessment of insulin resistance. Changes in peak oxygen consumption, 1-repetition maximum strength, vastus lateralis muscle, and subcutaneous adipose thicknesses, and waist circumference were also assessed. RESULTS: Ten weeks of MMIT substantially improved glucose disposal rate by 27.5% (90% confidence interval, 1.2%-60.7%) and 24.8% (-5.4% to 64.8%) in the whey and control groups, respectively. There were likely and possible reductions in fasting blood glucose by -17.4% (-30.6% to -1.6%) and homeostatic model assessment of insulin resistance by -14.1% (-25.3% to 1.08%) in the whey group; however, whey effects were not clearly beneficial to glycemic outcomes relative to the control. MMIT also clearly substantially improved 1-repetition maximum by 20.6% (16.3%-24.9%) and 22.7% (18.4%-27.2%), peak oxygen consumption by 22.6% (12.0%-26.2%) and 18.5% (10.5%-27.4%), and vastus lateralis muscle thickness by 18.9% (12.0%-26.2%) and 18.6% (10.5%-27.4%) and possibly reduced waist circumference by -2.1% (-3.1% to -1.0%) and -1.9% (-3.7% to -0.1%) in the control and whey groups, respectively, but the whey-control outcome was trivial or unclear. CONCLUSIONS: A clinically meaningful enhancement in glycemic control after 10 wk of MMIT was not clearly advanced with peritraining whey protein supplementation in middle-age men with T2D.