Treatment of obesity

Efficacy of WBV as a modality for inducing changes in body composition, aerobic fitness, and muscular strength: a pilot study

The purpose of this pilot study was to evaluate the effectiveness of whole body vibration (WBV) training as a modality for inducing changes in body composition, cardiovascular condition, and muscular strength in sedentary postmenopausal women. WBV training was compared with other training regimens, ie, aerobic training and circuit resistance training, commonly used to promote weight loss, cardiovascular conditioning, and muscular strength. Postmenopausal women (aged 48–60 years) were randomly assigned to WBV training, circuit resistance training, or aerobic training. Participants trained three times per week for 8 weeks. The training regimens were progressive in nature, with increases in training intensity and duration occurring throughout the 8-week period. Body composition was assessed using dual-energy X-ray absorptiometry analyses. A modified Bruce treadmill protocol was used to assess aerobic capacity (VO_2peak) and time to peak exhaustion. Upper and lower body strengths were determined by one repetition maximum (1-RM) chest and leg presses, respectively. Variables were analyzed using separate 3 (exercise mode) × 2 (time) repeated-measures analysis of variance with effect sizes due to the small sample size. No significant main effects or interactions were seen for any body composition variable; however, moderate to large effect sizes (η²=0.243 and η²=0.257) were detected regarding interactions for percent body fat and lean body mass favoring aerobic training and circuit resistance training. For VO_2peak, no significant main effects or interactions were detected (time, η²=0.150; P=0.11; time × group, η²=0.139; P=0.30); but a significant time effect was observed for time to peak exhaustion (η²=0.307; P=0.017). A significant interaction for upper body strength (η²=0.464; P=0.007), and main effect for time in lower body strength (η²=0.663; P=0.0001) was detected. Post hoc analysis indicated a significant increase in upper body strength for circuit resistance training (P=0.023) and a decrease for WBV training (P=0.015). Our results indicate that WBV may not be an effective alternative to traditional training with regard to body composition or aerobic capacity, but could have a positive impact on lower body strength.

Effects of mild aerobic exercise and a mild hypocaloric diet on plasma leptin in sedentary women

1. The present study was conducted to investigate whether mild aerobic exercise and a mild hypocaloric diet, instead of severe restrictions on caloric intake, would affect weight reduction and plasma leptin concentrations. 2. Forty-one middle-aged sedentary women (15 obese and 26 non-obese) participated in a 12 week lifestyle-modification programme to reduce cardiovascular risk factors. Bodyweight, body composition, plasma leptin concentrations, serum lipid profiles, fasting plasma glucose and fasting plasma insulin were measured before and after the 12 week intervention. The intervention consisted of aerobic exercise, corresponding to approximately 50% of maximal oxygen consumption, and personal diet counselling. 3. Bodyweight decreased by (mean +/- SD) 3.9 +/- 3.4 kg in the obese group (P < 0.05) and by 1.7 +/- 1.8 kg in the non-obese group (P < 0.05). The plasma leptin concentration decreased significantly from 14.7 +/- 5.3 to 8.9 +/- 3.6 ng/mL in the obese group (P < 0.001) and from 7.6 +/- 3.9 to 5.6 +/- 2.2 ng/mL in the non-obese group (P < 0.01). 4. Overall, for all subjects, both pre- and postintervention, the plasma leptin concentration was significantly correlated with body mass index (BMI; pre-intervention: r = 0.73, P < 0.0001; postintervention: r = 0.67, P < 0.0001), fat mass (FM; pre-intervention: r = 0.74, P < 0.0001; postintervention: r = 0.63, P < 0.0001) and fasting plasma insulin (pre-intervention: r = 0.66, P < 0.001; postintervention: r = 0.45, P < 0.01). The change in plasma leptin concentration was significantly correlated with the respective changes in BMI (r = 0.64, P < 0.0001), FM (r = 0.48, P < 0.01) and fasting plasma insulin (r = 0.58, P < 0.0001). Interestingly, the ratio of plasma leptin concentration to BMI or FM diminished significantly after intervention. In addition, we found that the plasma leptin concentration decreased in participants whose FM did not decrease. These results suggest that the production of leptin per unit FM decreased after intervention. 5. Mild aerobic exercise and a mild hypocaloric intake decreased body mass and the plasma leptin level in Japanese middle-aged sedentary women. This decrease in plasma leptin levels was likely to be associated with weight reduction plus some unknown factor(s).

Syndrome-AC: non-insulin-dependent diabetes mellitus and the anabolic/catabolic paradox

When an organism is starving, infected or injured, the body initiates a catabolic response that, among other things, creates insulin resistance. While many possible mechanisms and numerous loci of insulin resistance have been studied, a theme of inappropriately activated components of catabolic chemistry emerges. Patients with non-insulin-dependent diabetes mellitus (NIDDM) have elevated blood levels of glucagon, cortisol, fatty acids, protein, glucose and possibly acute phase reactants. Recent studies hint that this can occur with meals, resulting in a multilevel, multiorgan interference with glucose handling. This implies NIDDM is the result of the dietary activation of catabolic chemistry simultaneously with that of anabolic chemistry. We review the possibility that this is caused by the consumption of body tissue, the substance ordinarily endogenously released in starvation or injury. Activating the catabolic pathways when eating creates a hormonal paradox, forcing exaggerated insulin levels to compensate. Five case studies are reviewed.

Energy expenditure during walking and running in obese and nonobese prepubertal children

We measured body composition and energy expenditure during walking and running on a treadmill in 40 prepubertal children: 23 obese children (9.3 +/- 1.1 years of age; 46 +/- 10 kg (mean +/- SD)) and 17 nonobese matched control children (9.2 +/- 0.6 years of age; 30 +/- 5 kg). Energy expenditure was assessed by indirect calorimetry with a standard open-circuit method. At the same speed of exercise, the energy expenditure was significantly (p < 0.01) greater in obese than in control children, in both boys and girls. Expressed per kilogram of body weight or per kilogram of fat-free mass, the energy expenditure was comparable in the two groups. Obese children had a significantly (p < 0.01) larger pulmonary ventilatory response to exercise than did control children. Heart rate was comparable in boys and girls combined but significantly higher (p < 0.05) in obese subjects, if boys and girls were analyzed separately. These data indicate that walking and running are energetically more expensive for obese children than for children of normal body weight. The knowledge of these energy costs could be useful in devising a physical activity program to be used in the treatment of obese children.