Effects of social contexts on overweight and normal-weight children's food intake

This study investigates the effects of peer influence on the food intake of overweight and normal-weight children. A mixed factorial design was employed, with children's weight status (overweight vs. normal-weight) as a between-subjects factor, and social context (alone vs. group) as a within-subjects factor. A total of 32 children (n=17 overweight and n=15 normal-weight) between the ages of 6-10 years participated in this study. Findings from the random regression model indicated that overweight children ate more when with others than when alone, while in contrast normal-weight ate more with others than they did when alone. Therefore, social context differentially impacts the eating behavior of overweight and normal-weight children. This study underscores differences in responses to the social environment between overweight and non-overweight youths, and suggests that social involvement may be an important tool in treatment and prevention programs for overweight and obesity.     

Peer influence on youth's snack purchases: a laboratory analog of convenience store shopping

ObjectiveThis paper reports the results of two experiments using a laboratory analog to examine the influence of taxes and subsidies on youth's snack food purchases when alone (Experiment 1) and when in the presence of a same-gender peer (Experiment 2).MethodAdolescents (12–14-years-old) completed a purchasing task, during which prices of snack foods were manipulated, either alone in Experiment 1 (N = 37) or in the presence of an unfamiliar peer in Experiment 2 (N = 52).ResultsIn both experiments, purchases of unhealthy snacks decreased and purchases of healthy snacks increased when the price of unhealthy snacks were taxed (increased). In Experiment 1 (alone), participants did not purchase more healthy snacks when the price of these snacks were subsidized (decreased). However, in Experiment 2 (when participants were in the presence of a peer), participants purchased more healthy snacks when these snacks were subsidized.ConclusionTaxes and subsidies affect adolescents' snack purchasing, as does the presence of peers. The results of this study highlight factors that influence healthy and unhealthy snack purchasing behavior in young adolescents.     

Food reinforcement, delay discounting and obesity

Choice is a central construct in behavioral economics, with choice research divided into choice of concurrent alternative reinforcers, which is conceptualized as relative reinforcing value, or choice of small immediate versus larger delayed rewards, usually of the same commodity, which is conceptualized as delay of gratification and delay discounting. Relative reinforcing value, delay of gratification and delay discounting paradigms can be used to study obesity, which involves strong motivation to obtain and consume food reinforcers. Strong food reinforcement and difficulties in delay of gratification are risk factors for child weight gain, and both are related to individual differences in overweight/obesity. Delay discounting interacts with food reinforcement to predict energy intake. We provide a selective review of research on each of these areas, and argue that the division of choice into reinforcing value versus delay discounting is based on an arbitrary definition based on the temporality of choices. We present a model that integrates reinforcing value and delay discounting approaches. Implications of this theoretical approach to better understand excess energy intake and obesity are discussed.The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.     

Contemporary outcomes of palliative transurethral resection of the prostate in patients with locally advanced prostate cancer

Background

Advanced prostate cancer may cause significant local complications which affect quality of life, including bladder outlet obstruction and hematuria. We performed a detailed review of our outcomes of palliative transurethral resection of the prostate (pTURP) in the era of taxane chemotherapy and potent androgen receptor antagonists at our tertiary-care institution.

The effect of peer influence on the amount of physical activity performed in 8- to 12-year-old boys

The purpose of this study was to determine the amount of physical and sedentary activity normal-weight and at-risk-for/overweight boys perform when alone, with a peer of similar weight and with a peer of different weight. Participants included boys, ages 8-12 years, classified as either normal-weight (<85th BMI percentile; N = 12) or at-risk-for/overweight (<85th BMI percentile; N = 12). At-risk-for/ overweight boys allocated a greater amount of time to sedentary activities and accumulated fewer accelerometer counts than normal-weight boys in the alone condition. Once paired with a peer of either similar or different weight there were no differences between groups. These results indicate the presence of an unknown peer has a positive effect on at-risk-for/overweight children's physical activity behavior.     

Impact of simulated ostracism on overweight and normal-weight youths' motivation to eat and food intake

There is growing evidence that the experience of being ostracized can impair individuals' abilities to self-regulate, which in turn, leads to negative health behaviors, such as increased unhealthy eating. Research has focused on adults, but deficits in eating regulation in response to ostracism may be particularly detrimental for overweight or obese youth. This study examines the effects of a brief episode of ostracism on the motivation to eat and food intake of overweight and normal-weight young adolescents (M age=13.6 years). A computerized ball-tossing game (Cyberball) was used to induce ostracism or inclusion. Following the inclusion/ostracism manipulation, all participants completed an operant computer task to earn points exchangeable for portions of food or for time socializing with an unfamiliar peer. Participants' responses for food and their subsequent energy intake were recorded. As hypothesized, ostracized overweight participants responded more for food and had a greater energy intake than overweight participants in the inclusion/control condition; whereas this was not the case for normal-weight participants. These results are important as studies indicate that overweight and obese youth may be at risk of social isolation and peer difficulties. Social adversity, if left unchanged, may increase the difficulty of promoting long-term changes in overweight youths' health behaviors.     

Effect of peers and friends on youth physical activity and motivation to be physically active

Objective To test whether the presence of a peer or a friendincreases the motivation to be physically active in overweightand non-overweight youth in a laboratory setting. Methods Youthmotivation to be physically active as a function of the socialcontext was measured using a computerized relative reinforcingvalue task to earn points exchangeable for physical and/or sedentaryactivities. Results The presence of a friend (p<.001)increased youth's; motivation to be physically active. The presenceof a peer increased overweight youth's; motivation to be physicallyactive, whereas this was not the case for lean youth (p=.47).Participants biked a greater distance in the presence of a friendthan when alone (p<.001). Overweight youth biked a greaterdistance in the presence of a peer than when alone, while thiswas not the case for lean youth (p=.23). Conclusions Friendshipsmay increase youth's; motivation to engage in physical activityand promote greater physical activity in non-overweight andoverweight youth.     

Influence of peers and friends on children's and adolescents' eating and activity behaviors

Obesity during childhood and adolescence is a growing problem in the United States, Canada, and around the world that leads to significant physical, psychological, and social consequences. Peer experiences have been theoretically and empirically related to the "Big Two" contributors to the obesity epidemic, unhealthy eating and physical inactivity. In this article, we synthesize the empirical literature on the influence of peers and friends on youth's eating and physical activity. Limitations and issues in the theoretical and empirical literatures are also discussed, along with future research directions. In conclusion, we argue that the involvement of children's and adolescents' peer networks in prevention and intervention efforts may be critical for promoting and maintaining positive behavioral health trajectories. However, further theoretical and empirical work is needed to better understand the specific mechanisms underlying the effects of peers on youth's eating and physical activity.