Exercise-induced weight loss preferentially reduces abdominal fat.

PURPOSE: To investigate whether abdominal fat is reduced in response to substantial weight loss induced by exercise in young obese men. METHODS: Thirty obese men (mean age 19.8 +/- 0.6 yr) were evaluated before (pretraining) and after (posttraining) 4 months of regimented training in the Singapore Armed Forces. There were 30 obese male subjects (mean age 19.2 +/- 1.3 yr) without training who were monitored as control subjects. Fat free mass (FFM), fat mass, and percent body fat were determined from skinfold measurements. Differences between pre- and posttraining responses were analyzed with a paired -test. RESULTS: Subjects lost 12.0 +/- 3.6 kg (P < 0.001) from pre- to posttraining, which was attributable to a reduction in fat mass (P < 0.001), as FFM was unchanged. Both waist circumference (WC) and hip circumference (HC) decreased (P < 0.01), the reduction in WC (13.7%) being greater than the reduction in HC (7.7%) as reflected by the decrease in waist-to-hip ratio (WHR; P < 0.001). These data reveal that large exercise-induced weight losses are associated with maintenance of FFM. The significant reduction in WHR indicates a greater mobilization of abdominal fat and a preferential loss of fat from this region. CONCLUSIONS: Large exercise-induced weight loss is associated with a preferential reduction in abdominal fat and a corresponding maintenance of FFM. Such an effect on body composition should reduce disease risk and the eventual weight regain that typically follows diet-induced weight losses with obese subjects.

Is there an optimal macronutrient mix for weight loss and weight maintenance?

Low carbohydrate diets are gaining popularity, however there is no clear consensus regarding their safety and efficacy for weight loss. Proponents of these diet plans advocate dramatic reductions in carbohydrate intake to combat insulin resistance and hyperinsulinaemia, which they claim are responsible for obesity. There are no long-term studies that directly compare the weight loss potential of low versus higher carbohydrate diets. Evidence from randomized controlled trials suggests that low carbohydrate diets may enable short-term weight loss by facilitating reduced energy intakes, however poor dietary compliance may prevent long-term success. Unbalanced nutrient profiles may increase the risk of adverse health consequences in adherents. Low carbohydrate diets should not be recommended at this time due to a lack of adequate long-term follow up data. Successful weight loss occurs through the creation of a sustained energy deficit, and should be achieved through a combination of exercise and a nutritionally balanced and varied diet.

Does using the Internet facilitate the maintenance of weight loss?

OBJECTIVE: The purpose of this study was to investigate the effectiveness of a weight maintenance program conducted over the Internet. DESIGN: Longitudinal, clinical behavioral weight loss trial with 6-month in-person behavioral obesity treatment followed by a 12-month maintenance program conducted both in-person (frequent in-person support; F-IPS, minimal in-person support; M-IPS) and over the Internet (Internet support; IS). SUBJECTS: A total of 122 healthy, overweight adults (age=48.4+/-9.6, BMI=32.2+/-4.5 kg/m(2), 18 male) MEASUREMENTS: Body weight, dietary intake, energy expended in physical activity, attendance, self-monitoring, comfort with technology. RESULTS: Results (n=101) showed that weight loss did not differ by condition during treatment (8.0+/-5 vs 11+/-6.5 vs 9.8+/-5.9 kg, P=0.27 for IS, M-IPS and F-IPS, respectively). The IS condition gained significantly more weight than the F-IPS group during the first 6 months of weight maintenance (+2.2+/-3.8 vs 0+/-4 kg, P<0.05) and sustained a significantly smaller weight loss than both in-person support groups at the 1 y follow-up (-5.7+/-5.9 vs -10.4+/-9.3 vs -10.4+/-6.3 kg, P<0.05 for IS, M-IPS and F-IPS, respectively). Attendance at maintenance meetings was greater for the F-IPS than the IS condition over the 1 y maintenance program (54 vs 39%, P=0.04). Acceptability of assigned condition was higher for subjects in the F-IPS than IS condition. CONCLUSION: The results of this study suggest that Internet support does not appear to be as effective as minimal or frequent intensive in-person therapist support for facilitating the long-term maintenance of weight loss.

Does intentional weight loss affect mortality rate?

Short-term studies indicate that intentional weight loss among obese persons significantly improves physiologic variables. Hence, it is logical to conjecture that intentional weight loss would lead to long-term benefits and increased longevity. Herein, we review recent epidemiologic studies that investigate the weight loss-mortality association using a conservative analytic approach that included distinguishing between intentional and unintentional weight loss, adjusting for potential confounders, and excluding unhealthy subjects. On balance, results indicate that intentional weight loss appears to neither increase nor decrease mortality rate. Discussion focuses on the problems of addressing this important public health question with observational data.

Postpartum weight loss and infant feeding.

BACKGROUND: Women are often advised that lactation accelerates loss of the excess weight gained during pregnancy, but the evidence underlying this advice is sparse and conflicting. To help fill this gap, we assessed differences in the rate of postpartum weight loss in the first 9 months postpartum according to method of infant feeding. METHODS: Two hundred thirty-six women attending two public health clinics in Montreal were weighed in one to four routine infant immunization visits up to the 9th postpartum month. After each weighing, we administered a telephone questionnaire assessing the method of infant feeding (predominantly breast-feeding, mixed-feeding, or predominantly bottle-feeding) and potential confounders. Data were analyzed using unbalanced multivariate repeated measures linear regression. RESULTS: Infant feeding was not associated with statistically significant differences in the rate of weight loss. Gestational weight gain, postpartum smoking, and maternal birthplace were important predictors of postpartum weight change. CONCLUSION: Although our results cannot exclude an effect of more exclusive or more prolonged breast-feeding, breast-feeding as commonly practiced does not appear to influence the rate of postpartum weight loss. This information should be useful in counseling new or prospective mothers and in avoiding unrealistic expectations.

Serum leptin concentration and advanced gastrointestinal cancers: a case controlled study.

BACKGROUND: Serum leptin level is associated with appetite and energy expenditure in healthy individuals. We aimed to evaluate the serum leptin concentration and the other factors which may be associated with weight loss in patients with advanced gastrointestinal cancer. METHODS: Forty-four patients with advanced gastrointestinal cancer (25 gastric and 19 colorectal cancer) and 25 healthy controls were enrolled. Serum leptin levels were measured as ng/ml via enzyme linked immuno-sorbent assay (ELISA) method in all subjects. The difference in serum leptin concentration between cancer and control group, the factor associated with its serum level and the relationship between serum leptin concentration and weight loss was evaluated. RESULTS: Serum leptin concentration of cancer group was significantly lower than controls (p = 0.002). Female subjects had significantly higher serum leptin concentration than male subjects in control group (p = 0.01), while not in cancer group (p > 0.05). Serum leptin concentration was significantly related with gender in controls (p = 0.023, beta = 0.479), while no gender difference was observed in cancer group (p > 0.05). No relationship was found between serum leptin concentration and weight loss percentage in cancer group in linear regression analysis (p > 0.05). No significant difference was observed in serum leptin concentrations between colon and gastric cancer sub-groups (p > 0.05). CONCLUSION: Independently from the site of gastrointestinal tract, serum leptin concentration in advanced gastrointestinal cancer is lower than controls and it is not a determinant factor in weight loss. In contrast to healthy subjects, gender does not effect the serum leptin concentration in patients with advanced gastrointestinal cancer.

Effect of standard vs extended Roux limb length on weight loss outcomes after laparoscopic Roux-en-Y gastric bypass.

BACKGROUND: Increasing the length of the Roux limb in open Roux-en-Y gastric bypass (RYGB) effectively increases excess weight loss in superobese patients with a body mass index (BMI) >50 kg/m2. Extending the RYGB limb length for obese patients with a BMI < 50 could produce similar results. The purpose of this study was to compare the outcomes of superobese patients undergoing laparoscopic RYGB with standard (< or =100-cm) with those undergoing the procedure with an extended (150-cm) Roux limb length over 1-year period of follow-up. Methods: Retrospective data over 2.5 years were reviewed to identify patients with a BMI < 50 who underwent primary laparoscopic RYGB with 1-year follow-up ( n = 58). Forty-five patients (sRYGB group) received limb lengths < or = 100 cm, including 45 cm ( n = 1), 50 cm ( n = 2), 60 cm ( n = 6), 65 cm ( n = 1), 70 cm ( n = 1), 75 cm ( n = 3), and 100 cm ( n = 31). Thirteen patients (eRYGB group) received 150-cm limbs. Postoperative weight loss was compared at 3 weeks, 3 months, 6 months, and 1 year. RESULTS: Comparing the sRYGB vs the eRYGB group (average +/- SD), respectively: There were no significant differences in age (41.5 +/- 11.0 vs 38.0 +/- 11.9 years), preoperative weight (119.2 +/- 11.9 vs 127.8 +/- 12.5 kg), BMI (43.7 +/- 3.0 vs 45.2 +/- 3.5 kg/m2), operative time (167.1 +/- 72.7 vs 156.5 +/- 62.4 min), estimated blood loss (129.9 +/- 101.1 vs 166.8 +/- 127.3 cc), or length of stay (median, 3 vs 3 days; range, 2-18 vs 3-19). Body weight decreased over time in both groups, except in the sRYGB group between 3 and 6 months and 6 and 12 months after surgery and in the eRYGB group between 6 and 12 months. BMI also decreased over time, except in the eRYGB group between 6 and 12 months. Absolute weight loss leveled out between 6 and 12 months in both groups, with no increase after 6 months. Percent of excess weight loss did not increase in the eRYGB group after 6 months. An extended Roux limb did not significantly affect body weight, BMI, absolute weight loss, or precent of excess weight loss at any time point when the two groups were compared. A trend toward an increased proportion of patients with >50% excess weight loss ( p = 0.07) was observed in the extended Roux limb group. CONCLUSIONS: In this series, no difference in weight loss outcome variables were observed up to 1 year after laparoscopic RYGB. Thus, extending Roux limb length from < or =100 cm to 150 cm did not significantly improve weight loss outcome in patients with a BMI < 50 kg/m2.

What consumers want to know about commercial weight-loss programs: a pilot investigation.

OBJECTIVE: In 1999, the Partnership for Healthy Weight Management recommended that providers of commercial weight-loss programs (and products) voluntarily disclose information concerning the safety, costs, and central components of their programs, as well as the credentials of program staff. These guidelines were drafted without the benefit of data from consumers concerning the specific information they desired. The present study provides such data. RESEARCH METHODS AND PROCEDURES: Participants were 90 women with a mean age of 44.02 +/- 9.17 years and body mass index of 36.11 +/- 4.82 kg/m(2) who were participants in one of two randomized weight-control trials. Before treatment, respondents were asked to imagine that they were "looking for a weight-loss plan" and to rate how important each of 16 factors would be in helping them select a plan. Ratings were made using 5-point scales, anchored by "not at all important" and "extremely important," (scored 1 and 5, respectively). Participants also identified the five factors that they thought were the most important, as well as the single most important. RESULTS: The mean rating for the importance of safety (4.57 +/- 0.60) was significantly greater than that for each of the 15 other variables (all p values < 0.05). In addition, significantly more respondents (27.8%) selected safety as the single most important factor than any other variable (all p values < 0.05). Other factors that were consistently judged as very important included information about diet (4.38 +/- 0.68), behavior modification (4.32 +/- 0.76), cost (4.19 +/- 0.92), and maintenance of weight loss (4.15 +/- 0.91). Staff credentials (3.88 +/- 0.83) were among the lowest rated items. DISCUSSION: The results generally support the disclosure guidelines proposed by the Partnership for Health Weight Management. Consumers, however, seem to desire information about weight loss, in addition to that concerning safety, cost, and central program components.