To assess the effects of reducing television viewing and computer use on children's body mass index (BMI) as a risk factor for the development of overweight in young children.Design: Randomized controlled clinical trial.Setting: University children's hospital.Participants: Seventy children aged 4 to 7 years whose BMI was at or above the 75th BMI percentile for age and sex.Interventions: Children were randomized to an intervention to reduce their television viewing and computer use by 50% vs a monitoring control group that did not reduce television viewing or computer use.Main Outcome Measures: Age-and sex-standardized BMI (zBMI), television viewing, energy intake, and physical activity were monitored every 6 months during 2 years.Results: Children randomized to the intervention group showed greater reductions in targeted sedentary behavior (PϽ.001), zBMI (PϽ.05), and energy intake (PϽ.05) compared with the monitoring control group. Socioeconomic status moderated zBMI change (P =.01), with the experimental intervention working better among families of low socioeconomic status. Changes in targeted sedentary behavior mediated changes in zBMI (PϽ.05). The change in television viewing was related to the change in energy intake (PϽ.001) but not to the change in physical activity (P =.37). Conclusions:Reducing television viewing and computer use may have an important role in preventing obesity and in lowering BMI in young children, and these changes may be related more to changes in energy intake than to changes in physical activity.

No abstract

Habituation is influenced by variety of foods, and overweight children increase energy intake more with variety than do leaner children. Research is needed to evaluate mechanisms of how variety influences the motivation to eat and energy intake, and how the variety effect can be used to influence intake across multiple eating occasions in children.

The rate of habituation to food is inversely related to energy intake, and overweight children may habituate slower to food and consume more energy. This study compared patterns of sensitization, as defined by an initial increase in operant or motivated responding for food, and habituation, defined by gradual reduction in responding, for macaroni and cheese and pizza in overweight and nonoverweight 8−12 year-old children. Non-overweight children habituated faster to both foods than overweight children (p = 0.03). All children recovered motivated responding for a new food (chocolate). Overweight children consumed more energy than non-overweight children (p = 0.0004). Children who showed a sensitization in responding consumed more food (p = 0.001), and sensitization moderated the effect of overweight on habituation, with slower habituation for overweight children who sensitized (p < 0.0001). This study replicates previous data on overweight/ non-overweight differences in habituation of food and of energy intake, and provides new information that individual differences in sensitization and habituation of motivated responding to food cues may be associated with a sustained motivation to eat, resulting in greater energy intake. KeywordsHabituation; motivated responding; energy intake; obesity; children Habituation to food, as defined by a gradual reduction in responding to repeated presentations of a stimulus (Groves & Thompson, 1970) occurs in rodents, non-human primates and humans across a wide variety of responses. Habituation to food stimuli have been observed in rats using mouthing responses Swithers-Mulvey, Miller, & Hall, 1991;Swithers-Mulvey, Mishu, & Hall, 1992;Swithers, 1995Swithers, , 1996Swithers & Hall, 1994) and the electrophysiology of mouthing (Swithers, Westneat, & Hall, 1998), in non-human primates by habituation of single cell brain responses (Rolls, Sienkiewicz, & Yaxley, 1989;Rolls, Yaxley, & Sienkiewicz, 1990). Habituation to food has been observed in child and adult humans using salivation (Epstein, Rodefer, Wisniewski, & Caggiula, 1992;Epstein et al., 2003;, electrophysiology of mouthing in adults (Epstein & Paluch, 1997), and in motivated behavior, or operant responding to obtain food for Publisher's Disclaimer:This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. (Epstein et al., 2003;Myers Ernst & Epstein, 2002;Temple, Giacomelli, Roemmich, & Epstein, 2008;Temple et al., 2006). In each of these studies a decrement in response was observed to repeated presentations of the same food, with a recovery of responses when a new food was presented or the inhibition of habituati...

Background-Recruitment of participants for clinical trials requires considerable effort and cost. There is no research on the cost-effectiveness of recruitment methods for an obesity prevention trial of young children.