D.K. Tidwell

A meta-analysis of school-based obesity prevention programs demonstrates limited efficacy of decreasing childhood obesity.

Childhood obesity is a global concern. The objectives of this meta-analytical study were to evaluate the effectiveness of school-based childhood obesity prevention programs, and to examine program components (moderators). The methods included searching databases (PubMed, Google Scholar, and the universitys EBSCOhost Web service) as well as handsearching reference lists of articles published in English. Selection criteria for studies to be included in the meta-analysis were limited to studies that reported body mass index (BMI) or skinfold thickness as outcome measures and were school-based obesity prevention interventions; cross-sectional design studies were excluded. We hypothesized the meta-analysis would yield a summary effect size of magnitude which would indicate that school-based interventions have been effective in improving childrens BMI or skinfold thickness values. A total of 26 114 children from 27 school-based childhood obesity prevention programs provided 54 effect sizes. A random-effects model calculated a small summary effect size of 0.039 (95% confidence interval -0.013 to 0.092). Heterogeneity among studies was observed which disappeared after pooling studies that used a randomized controlled trial design with one program moderator (physical activity or nutrition). We failed to accept our hypothesis and concluded that overall, school-based interventions have not been effective for improving body mass index or skinfold thickness to curb childhood obesity; however, randomized controlled trials that focused on physical activity or nutrition appeared to produce promising results.

Comparison of the effects of adding fish high or low in n-3 fatty acids to a diet conforming to the dietary guidelines for Americans

OBJECTIVE To compare the effects of diets containing high or low amounts of n-3 fatty acids on lipid levels in men. DESIGN A continuous 40-day feeding study was conducted using a 5-day cycle menu. The control diet, which was fed the first 21 days of the trial, contained 32% of energy as fat and 44.4 g total dietary fiber per day. Total serum cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) were evaluated 1 day before the trial began and on days 21 and 41. SUBJECTS 17 men aged 21 to 42 years who were free-living individuals with no apparent illnesses or hyperlipidemia. INTERVENTION The treatment diets, which were substituted daily for the regular entrees for the last 19 days of the trial, contained 180 g/day of either farm-raised catfish or wild Alaskan salmon. STATISTICAL ANALYSES PERFORMED Serum data were analyzed using analysis of covariance with the initial values as the covariates. RESULTS After 21 days on the control diet, TC and TGs decreased; however, there were no further decreases during the last 19 days when fish was consumed. LDL-C remained unchanged after the first 21 days but was lower than the initial value by day 41. HDL-C levels were similar over the 40 days. There were no significant differences in lipid levels of men who consumed catfish and those who consumed salmon. APPLICATIONS/CONCLUSIONS Farm-raised catfish compared favorably to wild Alaskan salmon when incorporated into the total diet in regard to lipid levels in men.

A resting metabolic rate equation including bioelectrical impedance - derived lean body mass provides a better prediction in premenopausal African American women across a spectrum of body mass indices.

The purpose of this cross-sectional study was to develop, validate, and cross-validate an equation for predicting resting metabolic rate (RMR) in African American females. Data were collected from August 2004 to January 2005. Participants in the study included 100 African American women, 18 to 40 years old, with various body mass indices. Fifty participants were randomly selected to develop the equation and the remaining 50 were employed to test the equations. Bioelectrical impedance analysis (BIA), confirmed by dual-energy x-ray absorptiometry, was used to determine fat-free mass (FFM) and fat mass (FM) and RMR was measured by indirect calorimetry (ie, measured RMR [mRMR]) with a canopy system. A forward, stepwise, multiple regression analysis was performed with mRMR as the dependent variable and age, height, weight, FM, and FFM served as independent variables. The new Wells-Valliant equation was the only equation in this investigation that did not differ significantly from mRMR. When estimating RMR, it is imperative to select an equation that provides the best estimate of RMR for the population considered. The Wells-Valliant equation developed in this study includes FM and FFM, is more accurate than previous equations in estimating RMR in African American women, and can be calculated with more readily available BIA equipment.