Obesity Epidemiology

PREDICTORS AND CONSEQUENCES OF CHILDHOOD OBESITY 421sizes have been getting larger over time. 52,53 Moreover, many of these foods are high infat, particularly unhealthy fats such as saturated fat and trans fat.The consumption of fast food and other fried foods has been the focus of several recentstudies. Two large studies have observed that fast food intake was positively associatedwith caloric intake, 54,55 suggesting that fast-food consumption could lead to consumingmore calories than a child expends and therefore promote obesity. In the GUTS, Taveraset al. 55 observed that cross-sectionally the frequency of eating fried foods away fromhome was positively associated with intake of calories, trans fat, and sugar-sweetenedbeverages. One prospective study found that children who increased their consumptionof foods fried away from home from less than weekly to four to seven times a week overthe 1-year follow-up had larger increases in BMI than their peers. Moreover, in a 15-yearfollow-up of the CARDIA cohort, Pereira et al. 56 observed that both baseline frequencyof eating fast food and change in frequency of consuming fast food were independentlyassociated with changes in weight among blacks and whites; however, the associationwas stronger among whites. Although some studies have not observed a relationshipbetween fast food intake and weight status, 57 several other studies, including longitudinalstudies, support the hypothesis that consumption of fast food can promote excessiveweight gain and the development of obesity.Snack Food and SodaThere are numerous reasons that snack-food intake might increase the risk of becomingor remaining overweight. For example, snack foods may contribute to excessive caloricintake by being consumed in addition to regular meals, instead of as a replacement.Despite an ecological association between increasing prevalence of pediatric obesityand intake of snack foods over the past two decades, 3,58 the relationship between snackfood intake and weight change is not well understood. It is widely believed that the twoare positively associated, although the data are not conclusive. Among 173 Caucasiangirls followed from ages 5 to 9, Francis et al. 59 observed an association between weightgain and snack food consumption among children with at least one overweight parent.However, in two other longitudinal studies, no meaningful association between intakeof snack food and change in BMI was observed. 60,61 Unlike Francis et al., Field et al. 60observed that offsprings of overweight mothers gained more weight than their peers,but that there was not an independent association of snack-food intake and weightchange among children of lean mothers or overweight mothers. One limitation of all ofthese studies is that they did not assess snacking patterns, including snacking on itemsother than snack foods, such as cereal, smoothies, sandwiches, or breakfast foods ormain dishes that contain at least as many calories as many snack-food items. Therefore,more longitudinal studies that assess snacking behaviors and foods consumed assnacks are needed to better understand the relationship between snacking and excessiveweight gain.Several recent prospective studies have observed that intake of sugar-sweetened beveragespredicted greater weight gain. 62-64 Although the effect was relatively small in twoof these studies, the lack of a stronger association should not be misinterpreted to meanthat these foods and beverages, which are of low nutritional value but may be high incalories, do not need to be targeted as part of obesity-prevention efforts. Overall, theresults suggest that overconsumption of any type of food or beverage should result inweight gain since weight gain is a result of energy intake that is higher than energyexpenditure. Since there are a variety of healthy food and beverage options that containmore nutrients and minerals for the same or fewer calories per serving, it would be wise