Although vegetarian diets are considered generally protective against chronic disease, nutrient deficiencies, including protein, are possible due to low bioavailability from plant-based sources. The consequences of inadequate dietary protein include reduced lean body mass (LBM) and muscle weakness. This study examined relationships between protein intake, strength, and LBM in 37 underactive vegetarians and recorded the impact of protein supplementation (18 g/day mung bean protein) on these indices utilizing an eight-week, randomized, controlled, feeding trial. Both handgrip and knee flexor and extensor strength were measured at baseline and week eight. At baseline, LBM was significantly related to grams of protein consumed daily. LBM was also correlated to grip strength (r = 0.569, p < 0.001) and lower body strength (r = 0.763 to 0.784; p < 0.001). Twenty-five vegetarians completed the feeding trial, including 11 in the protein supplementation group (PRO) and 14 in the control group (CON). At the end of the trial, LBM and strength did not differ significantly between groups. However, the average percent change for grip, flexor, and extensor strength did differ between PRO and CON participants (+2.9 ± 7.2% and −2.6 ± 7.3% respectively, p = 0.05). Thus, there were strong associations between dietary protein, LBM, and strength in vegetarians and an indication that supplementary vegetarian protein increased strength in the absence of exercise and independent of LBM.

Decaffeinated green tea extract (dGTE) can increase fat oxidation during leg exercise, but dGTE is unsuitable for many people (e.g., those with injuries/disabilities), and its effects on arm exercise and women are unknown. Eight adults (23-37 years old, 4 women) performed an incremental arm cycle test to measure peak oxygen uptake (VO2peak), followed by four 1-h trials at 50% VO2peak. Subjects were randomly assigned to 650 mg of dGTE or placebo (PLA) for 4 weeks followed by a 4-week washout and crossover trial. Blood samples were obtained pre-exercise and post-exercise for glycerol and free fatty acid analysis. Respiratory gases were collected continuously. VO2 showed no differences across trials ((0.83-0.89) ± (0.19-0.25) L/min, p = 0.460), neither did energy expenditure ((264-266) ± (59-77) kcal, p = 0.420) nor fat oxidation (dGTE = 0.11 to 0.12 g/min vs. PLA = 0.10 to 0.09 g/min, p = 0.220). Fat oxidation as percentage of energy expenditure was not different for dGTE vs. PLA (23% ± 12% to 25% ± 11% vs. 23% ± 10% to 21% ± 9%, p = 0.532). Glycerol concentration increased post-exercise in all trials, independent of treatments (pre = (3.4-5.1) ± (0.6-2.6) mg/dL vs. post = (7.9-9.8) ± (2.6-3.7) mg/dL, p = 0.867, η2 = 0.005 for interaction), as did free fatty acid ((3.5-4.8) ± (1.4-2.2) mg/dL vs. (7.2-9.1) ± (2.6-4.5) mg/dL, p = 0.981, η2 = 0.000). Chronic dGTE supplementation had no effect on lipolysis and fat oxidation during arm cycle exercise in men and women.

This study examined the effect of moderate intensity stair stepping exercise on the glycemic response, and antioxidant capacity (TAC) during an oral glucose tolerance test (OGTT). Thirty participants (women = 12) completed 4 OGTTs during rest or stair walking bouts of 1, 3, and 10 min in a randomized order. Blood was collected at baseline and 30 min during the OGTTs and analyzed for glucose, insulin, TAC, and lactate. Glucose concentrations were decreased following the 10 min (-22.69 (-34.66 to -10.72) mg/dL, p < 0.002) and 3 min (-15.37 (-25.05 to -5.69) mg/dL, p < 0.004) bouts but not the 1 min bout (-6.18 (-19.54 to 7.18) mg/dL, p = 0.352). Insulin concentrations were decreased following the 10 min (-6.11 (-8.86 to -3.36 μIU/dL), p < 0.001) and 3 min (-2.589 (-4.54 to -0.63) μIU/dL, p < 0.012) bouts but not the 1 min bout (-0.37 (-1.87 to 1.13) μIU/dL, p = 0.616). Insulin sensitivity index values showed a significant increase in the 10-min trial (1.81 (0.03-3.58), p < 0.048), but not during the 3 min (0.65 (-0.66 to 1.96) p = 0.317) or 1 min trial (0.13 (-1.58 to 1.84) p = 0.878). There was no omnibus effect for trial in TAC (p = 0.132, η² = 0.07). There was no interaction between trial and time for blood lactate (p = 0.621, η² = 0.02). This study provides evidence bouts as short as 3 min decrease postprandial blood glucose and insulin levels but longer bouts are needed to affect insulin sensitivity.