Nil Whey Protein Effect on Glycaemic Control after Intense Mixed-Mode Training in T2D.

While intense endurance and resistance exercise training and whey protein supplementation have both been shown to independently improve glycaemic 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: To determine if peri-training whey protein supplementation combined with MMIT can improve glycaemic control.

METHODS: In a double-blind randomised controlled trial, 24 men (55.7±5.6 y) with T2D performed MMIT with whey (20 grams) or placebo control for 10 weeks. Glycaemic control was assessed via glucose disposal rate (GDR) during a euglycaemic insulin clamp, fasting blood glucose concentration (FBG), and HOMA-IR. Changes in peak oxygen consumption (VO2peak), 1-repetition maximum strength (1RM), Vastus lateralis (VL) muscle and subcutaneous adipose thicknesses (SAT), and waist circumference (WC) were also assessed.

RESULTS: 10-weeks of MMIT substantially improved GDR by 27.5% (90%CI 1.2%, 60.7%) and 24.8% (-5.4%, 64.8%) in the whey and control groups, respectively. There were likely and possible reductions in FBG by -17.4% (-30.6%, -1.6) and HOMA-IR by -14.1% (-25.3%, 1.08%) in the whey group, however, whey effects were not clearly beneficial to glycaemic outcomes, relative to control. MMIT also clearly substantially improved 1RM by 20.6% (16.3%, 24.9%) and 22.7% (18.4%, 27.2%), VO2peak by 22.6% (12.0%, 26.2%) and 18.5% (10.5%, 27.4%), VL muscle thickness by 18.9% (12.0%, 26.2%) and 18.6% (10.5%, 27.4%) and possibly reduced WC by -2.1% (-3.1%, -1.0%) and -1.9% (-3.7%, -0.1%) in the control and whey groups respectively, but the whey-control outcome was trivial or unclear.

CONCLUSION: A clinically-meaningful enhancement in glycaemic control following 10-weeks of MMIT was not clearly advanced with peri-training whey protein supplementation in middle-aged men with Type-2 diabetes.