Weight Loss on an energy-restricted, low-fat, sugar-containing diet in overweight sedentary men.

With the increasing prevalence of obesity in the United Kingdom, the search for an effective weight reducing diet is a priority in helping to reverse this trend. A 12-week dietary intervention study was carried out to test the effectiveness of an energy-restricted, low-fat, sugar-containing diet on weight loss in sedentary overweight men. The study also aimed to assess eating behaviour, to measure change in attitude towards sugar-containing foods and to measure the impact of the study on perceived quality of life. Subjects were recruited from three UK cities; Edinburgh, Birmingham and London. Seventy-six men, aged between 25 and 60 years, completed the study. Baseline diets were assessed by a 7-day diet diary. Compliance to the subsequent dietary advice was measured on four occasions post intervention, by 4-day diaries. Measures of body weight status were also monitored. Eating behaviour, attitudes towards sugar-containing foods and quality of life were assessed by questionnaire. Significant reductions in body weight (5.2%), body fat (11.2%) and waist:hip ratio (3%) were observed following reported dietary changes that included a reduction in reported energy intake of 3.2 MJ/day (770 kcal/day), a reduction in the percent energy from fat (from 38.1% to 26.2%), an increase in the percent energy from total carbohydrate (from 44.4% to 54%) and from protein (from 17.3% to 20.6%). Subjects scored relatively highly for dietary restraint and emotional eating, and were strongly influenced by external eating cues. On completion of the 12-week study, subjects had a more positive attitude towards sugar-containing foods and perceived an improved quality of life. It is concluded, therefore, that including sugar-containing foods in a weight-reducing diet may be an effective strategy to achieve a palatable, low-fat, high-carbohydrate diet, which promotes weight loss in overweight individuals.

Leptin levels are associated with fat oxidation and dietary-induced weight loss in obesity.

OBJECTIVE: To examine the relationship between fasting plasma leptin and 24-hour energy expenditure (EE), substrate oxidation, and spontaneous physical activity (SPA) in obese subjects before and after a major weight reduction compared with normal weight controls. To test fasting plasma leptin, substrate oxidations, and SPA as predictive markers of success during a standardized weight loss intervention. RESEARCH METHODS AND PROCEDURES: Twenty-one nondiabetic obese (body mass index: 33.9 to 43.8 kg/m(2)) and 13 lean (body mass index: 20.4 to 24.7 kg/m(2)) men matched for age and height were included in the study. All obese subjects were reexamined after a mean weight loss of 19.2 kg (95% confidence interval: 15.1-23.4 kg) achieved by 16 weeks of dietary intervention followed by 8 weeks of weight stability. Twenty-four-hour EE and substrate oxidations were measured by whole-body indirect calorimetry. SPA was assessed by microwave radar. RESULTS: In lean subjects, leptin adjusted for fat mass (FM) was correlated to 24-hour EE before (r = -0.56, p < 0.05) but not after adjustment for fat free mass. In obese subjects, leptin correlated inversely with 24-hour and resting nonprotein respiratory quotient (r = -0.47, p < 0.05 and r = -0.50, p < 0.05) both before and after adjustments for energy balance. Baseline plasma leptin concentration, adjusted for differences in FM, was inversely related to the size of weight loss after 8 weeks (r = -0.41, p = 0.07), 16 weeks (r = -0.51, p < 0.05), and 24 weeks (r = -0.50, p < 0.05). DISCUSSION: The present study suggests that leptin may have a stimulating effect on fat oxidation in obese subjects. A low leptin level for a given FM was associated with a greater weight loss, suggesting that obese subjects with greater leptin sensitivities are more successful in reducing weight.

Estimating changes in daily physical activity levels over time: implication for health interventions from a novel approach.

The aim of this study was to use a novel method to examine and compare physical activity levels in four different groups of men to investigate the impact of modernity on activity levels. Physical activity levels of four different groups of men were measured and compared, using a tri-axial accelerometer (Tracmor). The first group (HA = historically active) were actors in a historical theme park who play the part of Australian settlers 150 years ago, the second were sedentary modern-day office workers (MS = modern sedentary), the third men who had successfully lost weight (SWL) in a modern men's weight loss program and the last, men who were unsuccessful (UWL) in the same program. Men who had successfully lost weight in a weight loss program were active at a level similar to that of men performing activity at a level carried out historically. Both of these groups were in turn significantly more active than modern-day sedentary workers (p < 0.05) and men who had not been successful at losing weight (p < 0.01). A linear regression between weekly average activity levels and the degree of waist size loss showed a significant positive association (r = 0.52, p < 0.01). The data suggest that a higher activity level facilitates the maintenance of long-term weight loss and this level is likely to approximate activity levels in the past. For the prevention and treatment of obesity an increase in physical activity is necessary, because (long-term) weight loss or weight maintenance is unlikely to occur when people are as sedentary as most people are today.

Effect of duodenal-jejunal exclusion in a non-obese animal model of type 2 diabetes: a new perspective for an old disease.

BACKGROUND: The Roux-en-Y gastric bypass and the biliopancreatic diversion effectively induce weight loss and long-term control of type 2 diabetes in morbidly obese individuals. It is unknown whether the control of diabetes is a secondary outcome from the treatment of obesity or a direct result of the duodenal-jejunal exclusion that both operations include. The aim of this study was to investigate whether duodenal-jejunal exclusion can control diabetes independently on resolution of obesity-related abnormalities. METHODS: A gastrojejunal bypass (GJB) with preservation of an intact gastric volume was performed in 10- to 12-week-old Goto-Kakizaki rats, a spontaneous nonobese model of type 2 diabetes. Fasting glycemia, oral glucose tolerance, insulin sensitivity, basal plasma insulin, and glucose-dependent-insulinotropic peptide as well as plasma levels of cholesterol, triglycerides, and free fatty acids were measured. The GJB was challenged against a sham operation, marked food restriction, and medical therapy with rosiglitazone in matched groups of animals. Rats were observed for 36 weeks after surgery. RESULTS: Mean plasma glucose 3 weeks after GJB was 96.3 +/- 10.1 mg/dL (preoperative values were 159 +/- 47 mg/dL; P = 0.01). GJB strikingly improved glucose tolerance, inducing a greater than 40% reduction of the area under blood glucose concentration curve (P < 0.001). These effects were not seen in the sham-operated animals despite similar operative time, same postoperative food intake rates, and no significant difference in weight gain profile. GJB resulted also in better glycemic control than greater weight loss from food restriction and than rosiglitazone therapy. CONCLUSIONS: Results of our study support the hypothesis that the bypass of duodenum and jejunum can directly control type 2 diabetes and not secondarily to weight loss or treatment of obesity. These findings suggest a potential role of the proximal gut in the pathogenesis the disease and put forward the possibility of alternative therapeutic approaches for the management of type 2 diabetes.