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Objective:As large weight losses are rarely achieved through any method except bariatric surgery, there have been no studies comparing individuals who initially lost large amounts of weight through bariatric surgery or non-surgical means. The National Weight Control Registry (NWCR) provides a resource for making such unique comparisons. This study compared the amount of weight regain, behaviors and psychological characteristics in NWCR participants who were equally successful in losing and maintaining large amounts of weight through either bariatric surgery or non-surgical methods.Design:Surgical participants (n=105) were matched with two non-surgical participants (n=210) on gender, entry weight, maximum weight loss and weight-maintenance duration, and compared prospectively over 1 year.Results:Participants in the surgical and non-surgical groups reported having lost approximately 56 kg and keeping 13.6 kg off for 5.5±7.1 years. Both groups gained small but significant amounts of weight from registry entry to 1 year (P=0.034), but did not significantly differ in magnitude of weight regain (1.8±7.5 and 1.7±7.0 kg for surgical and non-surgical groups, respectively; P=0.369). Surgical participants reported less physical activity, more fast food and fat consumption, less dietary restraint, and higher depression and stress at entry and 1 year. Higher levels of disinhibition at entry and increased disinhibition over 1 year were related to weight regain in both groups.Conclusions:Despite marked behavioral differences between the groups, significant differences in weight regain were not observed. The findings suggest that weight-loss maintenance comparable with that after bariatric surgery can be accomplished through non-surgical methods with more intensive behavioral efforts. Increased susceptibility to cues that trigger overeating may increase risk of weight regain regardless of initial weight-loss method.International Journal of Obesity (2009) 33, 173–180; doi:10.1038/ijo.2008.256; published online 2 December 2008 [ABSTRACT FROM AUTHOR]

This study sought to determine the influence of 16 months of progressive aerobic exercise on excess postexercise oxygen consumption (EPOC) and the extent EPOC contributed to weight management. Twenty-five overweight/obese women and 16 overweight/obese men participated in a 16-month exercise program (moderate-intensity treadmill walking) that progressed across the first 26 weeks to 5 days·wk-1, 45 min·session-1, and 75% HRR. Three-hour EPOC was measured at baseline, 9 months, and 16 months by indirect calorimetry in response to an exercise session (treadmill walking), in which energy expenditure (EE) was estimated from the participant's previous 10 exercise sessions. For women, EPOC was 7.5 ± 4.9, 9.6 ± 7.6, and 6.5 ± 6.5 L at baseline, 9 months, and 16 months, respectively (p > 0.05). For men, EPOC increased from baseline (11.8 ± 6.8 L) to 9 months (13.5±8.6 L) (p<0.05) with no further increase at 16 months (13.5 ± 11.0 L). Change in EPOC was correlated with change in EE at 9 months (r= 0.65; p <0.05) and 16 months (r=0.58; p<0.05) for men but not women. Progressive long-term exercise significantly influenced EPOC in overweight/obese men but not women. Change in volume of exercise likely explained the increase in energy expenditure during EPOC in men. EPOC contributed modestly to EE compared to the exercise itself. [ABSTRACT FROM AUTHOR]

OBJECTIVE:: To assess the validity and reliability of a hand-held indirect calorimeter. DESIGN:: Resting metabolic rate (RMR) was measured on two separate mornings. SUBJECTS:: A heterogeneous sample of 41 healthy adults. MEASUREMENTS:: RMR using both a metabolic cart (Sensormedics 2900, SM-2900) and a hand-held indirect calorimeter (BodyGem™, BG). RESULTS:: There were no trial-to-trial differences in RMR measured by the BG (6756±163 vs 6697±163?kJ/day) or the SM-2900 (6400±163 vs 6396±167?kJ/day). RMR measured by the BG was significantly higher than that measured by the SM-2900 during both trials. In a sample of 10 subjects, the energy cost of holding the BG in position was determined to be (0.17±0.04?kJ/min, or 255±84?kJ/day). After applying this adjustment, the differences between systems were no longer significant during trial 1 (mean difference=101±67?kJ/day) or trial 2 (46±75?kJ/day). In overweight and obese individuals, RMR measured by the BodyGem™was more accurate than that estimated by the Harris-Benedict equations. CONCLUSION:: The BodyGem™provides valid and reliable measurements of RMR. The BodyGem™produces significantly higher values than the Sensor Medics 2900 indirect calorimeter, with the increase largely due to an increased energy demand required to hold the BG in position.International Journal of Obesity (2004) 28, 1479-1484. doi:10.1038/sj.ijo.0802643 Published online 24 August 2004 [ABSTRACT FROM AUTHOR]

OBJECTIVES: Low-fat high-carbohydrate diets are recommended to prevent weight gain in normal weight subjects and reduce body weight in overweight and obese. However, their efficacy is controversial. We evaluated the efficacy of ad libitum low-fat diets in reducing body weight in non-diabetic individuals from the results of intervention trials. DESIGN: Studies were identified from a computerized search of the Medline database from January 1966 to July 1999 and other sources. Inclusion criteria were: controlled trials lasting more than 2 months comparing ad libitum low-fat diets as the sole intervention with a control group consuming habitual diet or a medium-fat diet ad libitum. MAIN OUTCOME MEASURES: Differences in changes in dietary fat intake, energy intake and body weight. Weighted mean differences for continuous data and 95% confidence intervals (CIs) were calculated. RESULTS: Two authors independently selected the studies meeting the inclusion criteria and extracted data from 16 trials (duration of 2-12 months) with 19 intervention groups, enrolling 1910 individuals. Fourteen were randomized. Weight loss was not the primary aim in 11 studies. Before the interventions the mean proportions of dietary energy from fat in the studies were 37.7% (95% CI, 36.9-38.5) in the low-fat groups, and 37.4% (36.4-38.4) in the control groups. The low-fat intervention produced a mean fat reduction of 10.2% (8.1-12.3). Low-fat intervention groups showed a greater weight loss than control groups (3.2 kg, 95% confidence interval 1.9-4.5 kg; P<0.0001), and a greater reduction in energy intake (1138 kJ/day, 95% confidence interval 564-1712 kJ/day, P=0.002). Having a body weight 10 kg higher than the average pre-treatment body weight was associated with a 2.6±0.8 kg (P=0.011) greater difference in weight loss. CONCLUSION: A reduction in dietary fat without intentional restriction of energy intake causes weight loss, which is more substantial in heavier subjects. [ABSTRACT FROM AUTHOR]

In order to determine the influence of an antigen's physical properties on the development of cell-mediated immunity (CMI) in the lung following aerosol immunization, human serum albumin (HSA) was prepared in either a soluble or a particulate form, the latter being coupled to respirable, carboxylated latex heads. Antigen was administered via an aerosol to groups of guinea-pigs, twice weekly for up to 4 weeks. Additional groups of animals served as unexposed and unconjugated latex controls. Lymphoid cells for CMI assays were isolated from the lung by bronchopulmonary lavage and from blood for use in mitogen- and antigen-induced lymphocyte transformation assays, as well as indirect macrophage migration inhibition tests. Particulate HSA-exposed animals yielded the highest numbers of free lung cells containing predominantly macrophages, with up to 33% lymphocytes. These were followed by the latex control, soluble HSA and unexposed control groups, respectively. Only the animals exposed to particulate HSA, had evidence of antigen reactivation in the lung cell populations as measured by lymphocyte stimulation assays. In contrast, a response to polyclonal mitogens was found only in animals exposed to antigen in a soluble form. Data from macrophage depletion experiments suggest that the antigenicity of inhaled antigens may be due to the types and numbers of cells responding to the stimulus, and the subsequent role the alveolar macrophage may play in the modulation of cellular immunity. [ABSTRACT FROM AUTHOR]

In order to understand the mechanisms of cellular immune injury in hypersensitivity pneumonitis, the effect of type of antigen on cell-mediated immunity in guinea-pigs receiving respiratory immunization was studied. Lymphocytes obtained by pulmonary lavage were compared with those from peritoneal exudate following immunization with either a soluble protein, human serum albumin, or a particulate suspension of Thermoactinomyces vulgaris. Assays were obtained without mixing cells from these two sources. Statistically significant increases (13-22%) in the number of alveolar rosette-forming cells (RFC) were found in the animals immunized with either antigen, but only the particulate T. vulgaris was also capable of inducing a systemic increase of such cells. That this increase in RFC could be due to specifically reactive lymphocytes was demonstrated by the production of antigen-stimulated macrophage migration inhibition. Some evidence was obtained that indicated that T. vulgaris could act both as a non-specific B-cell stimulant and a specific T-cell activator. The concept of a hypothetical pulmonary `barrier' is discussed which must be overcome to induce systemic immune responses following respiratory immunization. T. vulgaris must be added to the list of known agents or means for overcoming this `barrier'. [ABSTRACT FROM AUTHOR]