Aim: To investigate timing of protein ingestion relative to resistance exercise training (RT) on body composition, cardiometabolic risk factors, glycaemic control and resting energy expenditure (REE) during weight loss on a high-protein (HP) diet in overweight and obese patients with type 2 diabetes (T2DM).
Methods: Thirty-four men/women with T2DM (age 57 ± 7 years and body mass index 34.9 ± 4.2 kg m(-2) ) were randomly assigned to the ingestion of a HP meal (860 kJ, 21 g protein, 0.7 g fat, 29.6 g carbohydrate) either immediately prior to RT or at least 2 h following RT. All participants followed a 16-week, energy-restricted (6-7 MJ day(-1) ), HP diet (carbohydrate : protein : fat 43 : 33 : 22) and participated in supervised RT (3 day week(-1) ). Outcomes were assessed pre- and postintervention at 16 weeks.
Results: There was an overall reduction in bodyweight (-11.9 ± 6.1 kg), fat mass (-10.0 ± 4.4 kg), fat-free mass (-1.9 ± 3.1 kg), waist circumference (-12.1 ± 5.3 cm), REE (-742 ± 624 kJ day(-1) ), glucose (-1.9 ± 1.7 mmol l(-1) ), insulin (-6.1 ± 6.7 mU l(-1) ) and glycosylated haemoglobin (-1.1 ± 0.1%), p ≤ 0.01 time for all variables, with no difference between groups (p ≥ 0.41 group effect). Strength improved and cardiometabolic risk factors were reduced similarly in both groups; single repetition maximum chest press 11.0 ± 8.7 kg, single repetition maximum lat pull down 9.9 ± 6.0 kg, total cholesterol -0.6 ± 0.5 mmol l(-1) , high-density lipoprotein cholesterol -0.1 ± 0.2 mmol l(-1) , low-density lipoprotein cholesterol -0.3 ± 0.5 mmol l(-1) , triglycerides -0.6 ± 0.7 mmol l(-1) , blood pressure (systolic/diastolic) -13 ± 10/-7 ± 7 mmHg (p ≤ 0.04 time effect, p ≥ 0.24 group effect).
Conclusion: A HP, energy-restricted diet with RT was effective in improving glycaemic control, body composition, strength and cardiometabolic risk factors in overweight/obese patients with T2DM irrespective of altering the timing of protein ingestion relative to RT.
© 2010 CSIRO Food and Nutritional Sciences.