The understanding of obesity’s etiology has broadened from an individual to a more comprehensive perspective of environmental influences, based in social ecological models. Interventions to tackle obesity are dependent on understanding interactions within complex systems and on changing modifiable risk factors with high impact at the population level. In this chapter, literature on social and behavioral factors associated with obesity was reviewed. Socioeconomic factors seem to be main drivers of obesity. This effect may act indirectly through mediators such as diet and physical activity. The transgenerational profile of both socioeconomic conditions and obesity should also be highlighted. Thus, these influences should be taken from a lifecourse perspective. The establishment of obesity is nested in early life and the family context, including feeding practices, parents’ dietary habits and lifestyles, and parental obesity, are proximal determinants of childhood obesity. Pregnancy, breastfeeding and weaning are identified as sensitive periods for establishing eating habits and therefore obesity development. Research has focused extensively on the effects of diet and physical activity on the energy balance; however, there seems to exist a lack of consistent associations. Evidence is more robust regarding the protective effects of vegetables, whole grains and the Mediterranean Diet, and the detrimental effect of sugar-sweetened beverages and sedentary behaviors, namely television viewing, particularly in children. Smoking and moderate alcohol drinking have been negatively associated with obesity, but a confounding effect of a general lifestyle profile cannot be excluded. The influence of smoking during pregnancy on later childhood obesity is supported by more robust evidence.
Keywords: Alcohol drinking, Body mass index, Childhood obesity, Diet, Energy balance, Epidemiologic factors, Epidemiologic studies, Family characteristics, Feeding behavior, Health behavior, Meta-analysis, Obesity, Physical activity, Smoking, Social determinants of health, Socioeconomic status, Weight gain.