There is substantial evidence that body weight and dietary and physical activity behaviors track from childhood to adulthood. Evidence regarding the specific age at which this tracking becomes tight is debatable, but most agree that it is prudent to try to ensure that young children's growth is within recommended healthy weight ranges and that health-promoting dietary and physical activity behaviors are learned at an early age. To this end, interventions that aim to prevent obesity at any age, including in young children, are generally regarded as worthwhile. However, there is much debate (and resistance, particularly among some health professionals) concerning the usefulness (and potential harm) of interventions that aim to treat obesity in young children. The comprehensive systematic review by Bluford et al. (1) in this issue of Obesity reviewed seven studies (five prevention studies; two treatment studies). Both of the intervention studies reported significant reductions in weight status or body fat. Such success was identified in only two of the five prevention studies, and these two studies targeted children and families at high risk of obesity. The sampling, setting, and delivery of the interventions of the studies included in this review were diverse. Nevertheless, the fact that some interventions have been found to be efficacious is good news. Whether this efficacy can be translated into effectiveness is another challenge for healthcare providers. One of the factors that appeared to improve the success of interventions (prevention and treatment alike) was a high level of active parental involvement (although at such a young age it is difficult to see how significant parental involvement could be avoided). The importance of parental involvement was also one of the main conclusions reached by other comprehensive summaries of the evidence base on the prevention and treatment of obesity in children that have been collated recently (2)(3). So, what to do? Working with parents, guardians, and childcare providers to help them provide healthy diets for young children appears to be the key. However, data from the Quebec Longitudinal Study of Child Development provide cautionary evidence against translating advice directly from the equivalent literature in adults (4). In their survey of 1550 children, picky eaters were reported less often among young children with excess weight compared with other children. Eating too much or too fast was more often characterized in overweight and obese children compared with others. Children with excess weight were more likely than others not to have breakfast or to live in a situation of food insecurity, two characteristics closely associated with family socioeconomic status. This survey from Quebec found no significant association between excess weight and the frequency with which the children had restaurant meals or the frequency with which they watched television during meals. It is also important to consider the data from cross sectional and qualitative studies, in addition to the data from controlled trials, in thinking about the best strategies to prevent and treat obesity in young children. One specific program will not meet the needs of all, and we should caution against translating what we know works in adults and older children to young children. What we do know is that the best predictor of childhood obesity is parental obesity, followed closely by socioeconomic status (5), and that parental involvement appears key in any successful strategy. The greatest gains may be made by encouraging parents, guardians, childcare providers, and, indeed, health professionals who give advice to parents on child health to be role models and take up a healthy lifestyle and avoid obesity. Where an individual's attempts to do this are restricted due to food insecurity, those responsible for ensuring public health should provide appropriate support. The commercial sector also has an important role in helping families consume a healthy diet that they enjoy, at a price they can afford.