Effects of Adherence to a Higher Protein Diet on Weight Loss, Markers of Health, and Functional Capacity in Older Women Participating in a Resistance-Based Exercise Program.

Resistance training and maintenance of a higher protein diet have been recommended to help older individuals maintain muscle mass. This study examined whether adherence to a higher protein diet while participating in a resistance-based exercise program promoted more favorable changes in body composition, markers of health, and/or functional capacity in older females in comparison to following a traditional higher carbohydrate diet or exercise training alone with no diet intervention. In total, 54 overweight and obese females (65.9 ± 4.7 years; 78.7 ± 11 kg, 30.5 ± 4.1 kg/m², 43.5 ± 3.6% fat) were randomly assigned to an exercise-only group (E), an exercise plus hypo-energetic higher carbohydrate (HC) diet, or a higher protein diet (HP) diet. Participants followed their respective diet plans and performed a supervised 30-min circuit-style resistance exercise program 3 d/wk. Participants were tested at 0, 10, and 14 weeks. Data were analyzed using univariate, multivariate, and repeated measures general linear model (GLM) statistics as well as one-way analysis of variance (ANOVA) of changes from baseline with [95% confidence intervals]. Results revealed that after 14 weeks, participants in the HP group experienced significantly greater reductions in weight (E -1.3 ± 2.3, [-2.4, -0.2]; HC -3.0 ± 3.1 [-4.5, -1.5]; HP -4.8 ± 3.2, [-6.4, -3.1]%, p = 0.003), fat mass (E -2.7 ± 3.8, [-4.6, -0.9]; HC -5.9 ± 4.2 [-8.0, -3.9]; HP -10.2 ± 5.8 [-13.2, ⁻7.2%], p < 0.001), and body fat percentage (E -2.0 ± 3.5 [-3.7, -0.3]; HC -4.3 ± 3.2 [-5.9, -2.8]; HP -6.3 ± 3.5 [-8.1, -4.5] %, p = 0.002) with no significant reductions in fat-free mass or resting energy expenditure over time or among groups. Significant differences were observed in leptin (E -1.8 ± 34 [-18, 14]; HC 43.8 ± 55 [CI 16, 71]; HP -26.5 ± 70 [-63, -9.6] ng/mL, p = 0.001) and adiponectin (E 43.1 ± 76.2 [6.3, 79.8]; HC -27.9 ± 33.4 [-44.5, -11.3]; HP 52.3 ± 79 [11.9, 92.8] µg/mL, p = 0.001). All groups experienced significant improvements in muscular strength, muscular endurance, aerobic capacity, markers of balance and functional capacity, and several markers of health. These findings indicate that a higher protein diet while participating in a resistance-based exercise program promoted more favorable changes in body composition compared to a higher carbohydrate diet in older females.

Cassia Cinnamon Supplementation Reduces Peak Blood Glucose Responses but Does Not Improve Insulin Resistance and Sensitivity in Young, Sedentary, Obese Women.

Cassia cinnamon has been suggested to lower blood glucose (BG) and serum insulin (SI) due to an improvement in insulin resistance (IR) and sensitivity (IS). This study compared the effects Cassia cinnamon had on calculated IR and IS values and BG and SI in response to an oral glucose tolerance test (OGTT) in young, sedentary, and obese women. On three separate days, 10 women had a fasted venous blood sample obtained. Participants were given 5 g of encapsulated placebo (PLC) or 5 g of encapsulated Cassia cinnamon bark (CASS). Three hours after the initial blood sample, another blood sample was obtained to calculate values for IS and IR. The participants then completed an OGTT by consuming a 75 g glucose solution. Blood was obtained 30, 60, 90, and 120 min following glucose ingestion. IS and IR were not significantly different between placebo and Cassia (p > .05). The peak BG concentration in response to the OGTT was significantly lower at the 30 min time point for CASS, as compared to PLC (140 ± 5.8 and 156 ± 5.2 mg/dL, p = .025); however, there was no significant difference between treatments for SI (p > .05). The area-under-the-curve responses for BG and SI were not significantly different between PLC and CASS (p > .05). This study suggests that a 5 g dose of Cassia cinnamon may reduce the peak BG response and improve glucose tolerance following an OGTT, but with no improvement in IS and IR in young, sedentary, obese women.

A single bout of resistance exercise does not promote excess postexercise energy expenditure in untrained young men with a family history of diabetes.

BACKGROUND: People with a family history of type 2 diabetes have lower energy expenditure (EE) and more obesity than those having no such family history. Resistance exercise (RE) may induce excess postexercise energy expenditure (EPEE) and reduce long-term risk for obesity in this susceptible group. PURPOSE: To determine the effect of RE on EPEE for 15 hr after a single exercise bout in healthy, untrained young men having a family history of type 2 diabetes. DESIGN: Seven untrained men (23 ± 1.2 years, BMI 24 ± 1.1) completed a 48-hr protocol in a whole room calorimeter. The first day served as a control day, with a moderate 40-min RE bout occurring on the second day. Differences in postexercise EE were compared with matched periods from the control day for cumulative 15-min intervals (up to 150 min) and 15 hr after the RE bout was completed. RESULTS: The most robust difference in EPEE between the experimental and control days was observed in the first 15-min postexercise period (M = 1.4Kcal/min; SD = 0.7; p < .05). No statistically significant differences in EPEE were noted beyond 90-min of continuous measurement. CONCLUSIONS: Young people with a family history of type 2 diabetes may not show EPEE after a single RE bout when observed for 15 hr after RE and long-term resistance training may be required to promote EPEE.

A carbohydrate-restricted diet during resistance training promotes more favorable changes in body composition and markers of health in obese women with and without insulin resistance.

OBJECTIVE: To determine whether sedentary obese women with elevated levels of homeostatic model assessment (HOMA) insulin resistance (ie, > 3.5) experience greater benefits from an exercise + higher-carbohydrate (HC) or carbohydrate-restricted weight loss program than women with lower HOMA levels. METHODS: 221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m(2)) participated in a 10-week supervised exercise and weight loss program. The fitness program involved 30 minutes of circuit-style resistance training 3 days per week. Subjects were prescribed low-fat (30%) isoenergetic diets that consisted of 1200 kcals per day for 1 week (phase 1) and 1600 kcals per day for 9 weeks (phase 2) with HC or higher protein (HP). Fasting blood samples, body composition, anthropometry, resting energy expenditure, and fitness measurements were obtained at 0 and 10 weeks. Subjects were retrospectively stratified into lower (LH) or higher (HH) than 3.5 HOMA groups. Data were analyzed by multivariate analysis of variance with repeated measures and are presented as mean ± standard deviation changes from baseline. RESULTS: Baseline HOMA levels in the LH group were significantly lower than those in the HH group (LH, 0.6 ± 0.7; HH, 6.3 ± 3.4; P = 0.001). Diet and training significantly decreased body weight (-3.5 ± 3 kg), fat mass (-2.7 ± 3 kg), blood glucose (-3%), total cholesterol (-4.5%), low-density lipoproteins (-5%), triglycerides (-5.9%), systolic blood pressure (-2.6%), and waist circumference (-3.7%), while increasing peak aerobic capacity (7.3%). Subjects in the HP group experienced greater weight loss (-4.4 ± 3.6 kg vs -2.6 ± 2.9 kg), fat loss (-3.4 ± 2.7 kg vs -1.7 ± 2.0 kg), reductions in serum glucose (3% vs 2%), and decreases in serum leptin levels (-30.8% vs -10.8%) than those in the HC group. Participants in the HH (-14.1%) and HP-HH (-21.6%) groups observed the greatest reduction in serum blood glucose. CONCLUSION: A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. Additionally, obese women who initiated training and dieting with higher HOMA levels experienced greater reductions in blood glucose following an HP diet.

A structured diet and exercise program promotes favorable changes in weight loss, body composition, and weight maintenance.

BACKGROUND: A number of diet and exercise programs purport to help promote and maintain weight loss. However, few studies have compared the efficacy of different methods. OBJECTIVE: To determine whether adherence to a meal-replacement-based diet program (MRP) with encouragement to increase physical activity is as effective as following a more structured meal-plan-based diet and supervised exercise program (SDE) in sedentary obese women. DESIGN: Randomized comparative effectiveness trial. PARTICIPANTS/SETTING: From July 2007 to October 2008, 90 obese and apparently healthy women completed a 10-week university-based weight loss trial while 77 women from this cohort also completed a 24-week weight maintenance phase. INTERVENTION: Participants were matched and randomized to participate in an MRP or SDE program. MAIN OUTCOME MEASURES: Weight loss, health, and fitness-related data were assessed at 0 and 10 weeks on all subjects as well as at 14, 22, and 34 weeks on participants who completed the weight maintenance phase. STATISTICAL ANALYSES PERFORMED: Data were analyzed by multivariate analysis of variance for repeated measures. RESULTS: During the 10-week weight loss phase, moderate and vigorous physical activity levels were significantly higher in the SDE group with no differences observed between groups in daily energy intake. The SDE group lost more weight (-3.1 ± 3.7 vs -1.6 ± 2.5 kg; P = 0.03); fat mass (-2.3 ± 3.5 vs -0.9 ± 1.6 kg; P = 0.02); centimeters from the hips (-4.6 ± 7 vs -0.2 ± 6 cm; P = 0.002) and waist (-2.9 ± 6 vs -0.6 ± 5 cm; P = 0.05); and, experienced a greater increase in peak aerobic capacity than participants in the MRP group. During the 24-week maintenance phase, participants in the SDE group maintained greater moderate and vigorous physical activity levels, weight loss, fat loss, and saw greater improvement in maximal aerobic capacity and strength. CONCLUSIONS: In sedentary and obese women, an SDE-based program appears to be more efficacious in promoting and maintaining weight loss and improvements in markers of health and fitness compared to an MRP type program with encouragement to increase physical activity.