To use a quantitative approach to evaluate the literature for quantity, quality, and consistency of studies of maternal and infant characteristics in association with breastfeeding initiation and continuation, and to conduct a meta-analysis to produce summary relative risks (RRs) for selected factors. A systematic review using PubMed and CINAHL through March 2016 was conducted to identify relevant observational studies in developed nations, reporting a measure of risk for 1 or more of 6 quantitatively derived, high impact factors in relation to either breastfeeding initiation or continuation. One author abstracted data using a predesigned database, which was reviewed by a second independent author; data evaluation and interpretation included all co-authors. These factors were summarized using standard meta-analysis techniques. Six high impact factors were identified (smoking [39 papers], mode of delivery [47 papers], parity [31 papers], dyad separation [17 papers], maternal education [62 papers], and maternal breastfeeding education [32 papers]). Summary RR from random-effects models for breastfeeding initiation were highest for high vs low maternal education (RR 2.28 [95% CI 1.92-2.70]), dyad connection vs not (RR 2.01 [95% CI 1.38-2.92]), and maternal nonsmoking vs smoking (RR = 1.76 [95% CI 1.59-1.95]); results were similar for breastfeeding continuation. Despite methodological heterogeneity across studies, relatively consistent results were observed for these perinatally identifiable factors associated with breastfeeding initiation and continuation, which may be informative in developing targeted interventions to provide education and support for successful breastfeeding in more families.

Background: Short-term experimental studies suggest that dietary variety may influence body fatness but no long-term human studies have been reported. Objective: The purpose of this study was to determine whether dietary variety within food groups influences energy intake and body fatness. Design: Seventy-one healthy men and women (aged 20–80 y), who provided accurate reports of dietary intake and completed a body-composition assessment, were studied. Results: Dietary variety was positively associated with energy intake within each of 10 food groups (r = 0.27–0.56, P < 0.05). In multiple regression analysis with age and sex controlled for, dietary variety of sweets, snacks, condiments, entrées, and carbohydrates (as a group) was positively associated with body fatness (partial r = 0.38, P = 0.001) whereas variety from vegetables was negatively associated (partial r = −0.31, P = 0.01) (R² = 0.46, P < 0.0001). In separate models, both a variety ratio (variety of vegetables/variety of sweets, snacks, condiments, entrées, and carbohydrates) and percentage dietary fat were significant predictors of body fatness (controlled for age and sex, partial r = −0.39 and 0.31, respectively, P < 0.01). However, dietary fat was no longer significantly associated with body fatness when the variety ratio and dietary fat were included in the same model. Conclusions: Our data, coupled with those of previous short-term studies, suggest that a high variety of sweets, snacks, condiments, entrées, and carbohydrates coupled with a low variety of vegetables promotes long-term increases in energy intake and body fatness. These findings may help explain the rising prevalence of obesity.

Background: The specific underlying causes of adult weight gain remain uncertain. Objective: The objective was to determine the association of 3 measures of eating behavior with weight gain and body mass index (BMI; in kg/m²) in adults. Design: Current dietary restraint, disinhibition, and hunger were assessed with the use of the Eating Inventory in 638 healthy, nonsmoking women aged 55–65 y. In addition, subjects reported their current weight and height, their weight for 6 age intervals, and changes in voluntary dietary energy restriction over the past 10 y. Current weight and height were validated in 10% of subjects. Results: Current disinhibition strongly predicted weight gain and current BMI (partial r = 0.27 and 0.34, respectively, both P < 0.001). Neither restraint nor hunger was a significant independent predictor of either variable, but the positive associations between disinhibition and both weight gain and BMI were attenuated by restraint (P = 0.016 and 0.010, respectively, after adjustment for confounding variables). In the subpopulation of women who reported a stable level of voluntary dietary energy restriction, disinhibition also strongly predicted weight gain and higher BMI, and restraint was negatively associated with weight gain (partial r = –0.17, P = 0.019). Conclusions: Higher disinhibition is strongly associated with greater adult weight gain and higher current BMI, and dietary restraint may attenuate this association when disinhibition is high. These findings suggest that eating behavior has an important role in the prevention of adult-onset obesity and that further studies are warranted.

McCRORY, MEGAN A., PAUL J. FUSS, NICHOLAS P. HAYS, ANGELA G. VINKEN, ANDREW S. GREENBERG, AND SUSAN B. ROBERTS. Overeating in America: association between restaurant food consumption and body fatness in healthy adult men and women ages 19 to 80. Obes Res.Purpose: To examine the association between the frequency of consuming restaurant food and body fatness in adults.Research Methods and Procedures: Usual free‐living dietary intake and the frequency of consuming food from seven different restaurant types (fried chicken, burger, pizza, Chinese, Mexican, fried fish, and “other”) were assessed by food frequency questionnaire in 73 healthy men and women [ages 19 to 80, body mass index (BMI) 18 to 331. In addition, body fatness (percent weight) was determined by hydrostatic weighing, and physical activity and other lifestyle parameters were assessed by questionnaire. The relationship between the frequency of consuming restaurant food and body fatness was determined after controlling for age, sex, and other confounders by using multiple regression techniques.Results: Restaurant food consumption averaged 7.5±8.5 (Standard Deviation) timedmonth. After controlling for age and sex, the frequency of consuming restaurant food was positively associated with body fatness (partial r = 0. 36, p = 0. 003). The strength of this association did not change after controlling for education level, smoking status, and alcohol intake, but after additionally controlling for physical activity, the partial r increased to 0. 42 (p = 0. 004). Total daily intakes of energy, fat, and fiber were significantly associated with restaurant food consumption frequency (r = 0. 59, 0. 28, and −0.45, respectively, p = 0.02 to 0.0001).Discussion: The frequency of consuming restaurant food was positively associated with increased body fatness in adults. The increasing proportion of household food income spent on food prepared away from home in the United States may therefore help explain the rising national prevalence of obesity.