M. Grimstvedt

Effects of a popular exercise and weight loss program on weight loss, body composition, energy expenditure and health in obese women.

ObjectiveTo determine the safety and efficacy of altering the ratio of carbohydrate and protein in low-energy diets in conjunction with a popular exercise program in obese women.DesignMatched, prospective clinical intervention study to assess efficacy of varying ratios of carbohydrate and protein intake in conjunction with a regular exercise program.ParticipantsOne-hundred sixty one sedentary, obese, pre-menopausal women (38.5 ± 8.5 yrs, 164.2 ± 6.7 cm, 94.2 ± 18.8 kg, 34.9 ± 6.4 kg·m-2, 43.8 ± 4.2%) participated in this study. Participants were weight stable and not participating in additional weight loss programs.MethodsParticipants were assigned to either a no exercise + no diet control (CON), a no diet + exercise group (ND), or one of four diet + exercise groups (presented as kcals; % carbohydrate: protein: fat): 1) a high energy, high carbohydrate, low protein diet (HED) [2,600; 55:15:30%], 2) a very low carbohydrate, high protein diet (VLCHP) [1,200 kcals; 63:7:30%], 3) a low carbohydrate, moderate protein diet (LCMP) [1,200 kcals; 50:20:30%] and 4) a high carbohydrate, low protein diet (HCLP) [1,200 kcals; 55:15:30%]. Participants in exercise groups (all but CON) performed a pneumatic resistance-based, circuit training program under supervision three times per week.MeasurementsAnthropometric, body composition, resting energy expenditure (REE), fasting blood samples and muscular fitness assessments were examined at baseline and weeks 2, 10 and 14.ResultsAll groups except CON experienced significant reductions (P < 0.05 – 0.001) in waist circumference over 14 weeks. VLCHP, LCHP and LPHC participants experienced similar but significant (P < 0.05 – 0.001) reductions in body mass when compared to other groups. Delta responses indicated that fat loss after 14 weeks was significantly greatest in VLCHP (95% CI: -5.2, -3.2 kg), LCMP (-4.0, -1.9 kg) and HCLP (-3.8, -2.1 kg) when compared to other groups. Subsequent reductions in % body fat were significantly greater in VLCHP, LCMP and HCLP participants. Initial dieting decreased (P < 0.05) relative REE similarly in all groups. All exercise groups significantly (P < 0.05) improved in muscular fitness, but these improvements were not different among groups. Favorable but non-significant mean changes occurred in lipid panels, glucose and HOMA-IR. Leptin levels decreased (P < 0.05) in all groups, except for CON, after two weeks of dieting and remained lower throughout the 14 week program. Exercise participation resulted in significant improvements in quality of life and body image.ConclusionExercise alone (ND) appears to have minimal impact on measured outcomes with positive outcomes apparent when exercise is combined with a hypoenergetic diet. Greater improvements in waist circumference and body composition occurred when carbohydrate is replaced in the diet with protein. Weight loss in all diet groups (VLCHP, LCMP and HCLP) was primarily fat and stimulated improvements in markers of cardiovascular disease risk, body composition, energy expenditure and psychosocial parameters.

Factors that contribute to and account for strength and work capacity in a large cohort of recreationally trained adult healthy men with high- and low-strength levels.

Abstract Kerksick, CM, Mayhew, JL, Grimstvedt, ME, Greenwood, M, Rasmussen, CJ, and Kreider, RB. Factors that contribute to and account for strength and work capacity in a large cohort of recreationally trained adult healthy men with high- and low-strength levels. J Strength Cond Res 28(5): 1246–1254, 2014—The factors that best account for differences in strength across all types of exercise, body types, and training histories are not well understood. The purpose of this study was to assess the effects of strength level and body composition on upper- and lower-body work capacity in adult men. From a cohort of 295 adult men (25.6 ± 7.5 years, 178 ± 8 cm, 85.2 ± 15 kg), low-strength (LS, n = 72) and high-strength (HS, n = 66) samples were selected based on 1 repetition maximum (1RM) bench press (BP) and leg strength (LP) values. Work capacity for each exercise was determined from the product of repetition weight (80% 1RM) and maximum repetitions-to-fatigue (RTF). Body composition was measured using dual-energy x-ray absorptiometry. The HS group was significantly greater than the LS group in total body mass and fat-free mass but not in age, height, fat mass, or %fat. Low-strength and HS groups were not significantly different (p > 0.05) in RTF for either BP (8.7 ± 3.1 vs. 8.3 ± 1.9 reps, respectively) or LP (15.6 ± 7.6 vs. 17.0 ± 6.3 reps, respectively), making the ratio of RTF for BP vs. LP nonsignificant (LS = 2.0 ± 1.0; HS = 2.2 ± 0.9). The HS group produced significantly greater (p < 0.001) absolute and relative work capacities for both BP and LP compared with the LS group. Repetitions-to-fatigue had a greater influence on BP (r2 = 0.74) and LP (r2 = 0.85) work capacities in the LS group than did RepWt (r2 = 0.07 and 0.28, respectively). In the HS group, RTF (r2 = 0.79) had a greater influence than RepWt (r2 = 0.10) on BP work capacity, whereas the 2 components were more similar for LP work capacity (r2 = 0.64 and 0.47, respectively). When evaluated at the same %1RM, muscular endurance is similar across divergent strength levels meaning that work capacity (load × reps) will be greater for HS individuals. Controlling for the influence of body composition variables (e.g., fat or fat-free mass) does not eliminate the difference in work capacity between strength groups suggesting that other factors are accounting for strength expression. Prescribing repetitions against a fixed relative load is largely dependent on exercise type and must be considered by strength and conditioning professionals.

Effects of the Curves?? Fitness & Weight Loss Program on Weight Loss and Resting Energy Expenditure

PURPOSE: The Curves fitness and diet program has become very popular among adult women with over 2 million women currently participating in the program. However, the efficacy of this program has yet to be examined. This study examined the efficacy of the Curves fitness and diet program on weight loss and resting energy expenditure (REE). METHODS: 123 sedentary women (38.7±8 yr; 93.2±19 kg; 44.8±4.8 % body fat) participated in a 14-wk exercise and diet program. Based on baseline testing, subjects were randomly assigned to an exercise and no diet group (ND+E); an exercise and high calorie mixed diet (2,600 kcals/d for 2-wks at 55% C, 15% P, 30% F; 8 wks at 40% C, 30% P, 30% F; 4 wks at 55% C, 15% P, 30% F) group (HCD+E); or, a low calorie high carbohydrate (LC-HCHO+E), high protein (LC-HP+E), or very high protein (LC-VHP+E) diet. The diets involved consuming 1,200 kcal/d for 2-wks and 1,600 kcal/d for 8-wks. Subjects then ingested 2,600 kcal/d and 1,200 kcal diet at 3/2, 3/2, 5/2, & 10/0 day intervals in an attempt to maintain weight loss and REE. Diets were standardized with 30% dietary fat with carbohydrate intake ranging from 40-55% on the HCD+E and LC-HCHO+E diets and protein intake ranging from 50-63% on the LC-HP+E and LC-VHP+E diets. Subjects participated in a supervised 30min resistance training circuit program that was interspersed with calisthenic exercises and performed 3-d per week. At 0, 2, 10, 10.4 and 14 weeks, body weight, body composition (DEXA), and REE measurements were obtained. Data were analyzed by repeated measures ANOVA and are presented as means ± SD changes from baseline for the ND+E, HCD+E, LCHCHO+E, LC-HP+E and LC-VHP+E groups, respectively. RESULTS: After 10 weeks, subjects experienced significant (p<0.001) weight loss (-0.2±2; -1.1±3.2; -4.6±3.1; -4.5±4.1; 6.2±5.0 kg) and fat mass loss (-0.5±1.7; -0.5±2.0; -3.0±2.1, 3.2±2.8, -4.0±3.5 kg) which was maintained or continued during the maintenance phase (-0.1±1.8 -1.3±3.3; -5.1±3.5; -5.4±4.9; 6.3±5.4 kg weight; -0.9±1.7; -1.0±3.0; -3.5±2.8; -3.6±3.4, 4.6±4.1 kg fat). The majority of the weight loss was fat (76100%). Weight loss was due in part to a significant gradual increase in REE during the study at week 10 (1.65±2.7 kcal/kg/d) and week 14 (1.94±2.8 kcal/kg/d). The greatest increase in REE occurred in the HCD+E group. CONCLUSIONS: The Curves fitness and weight loss program appears to increase REE and promote weight loss particularly when following one of the diet plans. Moreover, intermittent dieting following weight loss appears to be an effective way to maintain and/or promote weight loss as well as to increase REE. Supported in part by Curves International, Inc., Waco, TX Rationale The Curves fitness and weight loss program has become a very popular means of promoting health and fitness among women. The program involves a 30-minute circuit training program and a weight management program involving periods of moderate caloric restriction (1,200 to 1,600 calories per day) followed by short periods of higher caloric intake (2,600 calories per day). The program is designed to promote a gradual reduction in body fat while increasing strength and fitness. Although the program has been based on sound rationale, the effects of following this program have not been studied. The purpose of this study is to examine the acute and chronic effects of Curves International fitness and diet program on weight loss, body composition, and resting energy expenditure in sedentary overweight females.