1. Heritability and imprinting. Adoption studies tend to generate the lowest heritability estimates (30%), whereas twin studies provide the highest heritability estimates (70%). These observations are consistent with the “thrifty genotype hypothesis,” in which genes predisposing to energy conservation were preserved as a survival characteristic in former times of famine but become a liability in environments with plentiful food and low physical activity. There is also evidence that exposure to environmental factors early in life may affect metabolism, as described in the “thrifty phenotype theory.”

2. Most causes of obesity are described as idiopathic or exogenous, which consist of a combination of hereditary traits and a “toxic” environment. In addition to an environment where high-energy processed foods are abundant and sedentary behaviors are favored, parental feeding practices and restrained feeding may contribute to rapid weight gain especially in young children. Less than 5% of causes of obesity are defined as endogenous causes, due to human genetic syndromes displaying mendelian patterns of transmission or endocrinopathies (e.g., hypothyroidism, Cushing syndrome). However, emerging evidence from neuroimaging studies suggest that food intake may affect neurological pathways involved in substance abuse (e.g., cocaine, alcohol) and thus lead to compulsive eating behaviors.

1. Family lifestyle assessment. For toddlers and preschoolers who are gaining weight rapidly, parenting skills and parent style may either be supportive of or undermine positive feeding and activity level. Start by asking the parent (or guardian) if they have any concerns about the child’s eating behaviors or growth. Ask parents about feeding and activity dynamics. Assess to what extent the family is in agreement with Ellyn Satter’s division of responsibility in feeding.

“Parents are responsible for the what, when, and where of feeding. Children are responsible for the how much and whether of eating.”

Among older children and teens. Assess both past and present feeding dynamics, but also begin to ask the 5Ws “When, where, what, why, with whom.” Address the older child directly as he or she becomes the agent of change. Separate the parent and child to ask some questions.

In addition, identify who is in charge of buying, cooking, and serving food, and who “shares the refrigerator.” Assess food access by asking questions regarding the availability of grocery store(s) in the neighborhood, density of fast food restaurants in the area, funds for food, utilities and cooking facilities at home, and school meals assistance. Determine whether the family has to make difficult choices such as “heat or eat.”

Questions to ask the parent of a young child include the following:

Questions for parents and/or the older child/teen include the following:

3. Cultural history. Culture and country of origin may shape health beliefs about weight gain. Some cultures may value a more full-bodied appearance, which may be seen as a sign of good health and not a problem. Avoid “correcting” the belief and instead focus the discussion on risks, not appearances. Some cultural norms may value limited questioning of clinicians (i.e., sign of disrespect) or expect clinicians to do most of the talking during a consult (i.e., a sign of expertise). Modify key elements of your approach when motivational interviewing technique is used (Table 61-2). For example, limit the handing over of some of the decision-making responsibility to the family and focus on building self-efficacy to change behavior. Be aware that minimal eye contact and limited questioning by the family may not be a sign of poor motivation. Finally, raising awareness and concern about obesity may render people in communities of color less satisfied with themselves and less able to cope with one more thing for which a good solution cannot yet be offered.