Results from this study revealed that during childhood and into early adolescence, girls developing in families differing in parental overweight had divergent trajectories of weight gain and disinhibited overeating. The data provided support for the primary hypothesis that, relative to girls without overweight parents, girls living in families with overweight parents had greater BMI increases across this period. Additionally, daughters’ BMI increase from 5 to 13 years, as well as their risk for becoming overweight, was related to the number of overweight parents. Relative to girls with neither parent overweight, girls who had two overweight parents were 8.1 times more likely to be overweight at age 13. Overweight parents also reported higher levels of disinhibited eating than normal weight parents, and patterns of increase in girls’ disinhibited overeating during this same period of development also differed across parental weight status groups. At age 5, there were no systematic differences in BMI or disinhibited eating among girls, but diverging trajectories for BMI and disinhibited eating produced differences in both outcomes over time. Effects of parent overweight seem to be additive; girls with two overweight parents had the greatest gains in BMI and increases in disinhibited eating from 5 to 13 years of age.
The results of this study corroborate and extend previous studies reporting that having two overweight parents elevates children’s risk for rapid weight gain and becoming overweight during childhood and that having one parent overweight also elevates risk, relative to having neither parent overweight (9
). In , the BMI data for the four groups are imposed on the Centers for Disease Control and Prevention BMI percentiles growth charts (47
) to show the differing patterns of change across groups against the backdrop of the reference data. The mean BMI of girls with neither parent overweight consistently tracks just above the 50th percentile from 5 to 13 years of age. In contrast, the BMI trajectory among girls with both parents overweight crosses percentiles, from 5 to 9 years of age, beginning at the 75th percentile, approaching the 90th percentile by age 9, and remaining at that level at 11 and 13 years of age. The trajectory of upward crossing of BMI percentiles, as shown by the both parent overweight group in this study, has been identified by the American Academy of Pediatrics as indicative of growth patterns placing children at higher risk for childhood overweight and obesity (53
). These data, revealing that girls in this group were more than eight times more likely to become overweight, provide additional confirmation on this point.
Previous research has shown that disinhibited eating is consistently related to overweight among adults (29
) and children (34
), and these findings provide additional evidence for associations among disinhibited eating and elevated weight status among young girls. In addition, these findings revealed that, over time, disinhibited overeating increased among all groups, suggesting that such increases may be normative. These findings revealed group differences in patterns of change in BMI and differences in disinhibited eating; daughters of two overweight parents had significantly greater increases in BMI, significantly greater increases in disinhibited eating, and greater levels of disinhibited eating than girls with one or neither parent overweight. However, this pattern of association is not sufficient to causally link disinhibited eating to greater increases in BMI, given the lack of an experimental design. We have proposed elsewhere that restrictive parenting practices, which tend to be used by white, middle class parents with daughters who are more overweight, can promote disinhibited overeating. However, influence in parent-child dyads is bi-directional, suggesting that children’s weight status can be both a cause and a consequence of parental feeding practices (54
); therefore, these findings raise the possibility of causal links, which must be addressed in future studies.
Mothers’ but not fathers’ disinhibited eating was associated with daughters’ disinhibited eating, but these links between mother’s and daughters’ disinhibited eating did not emerge until later childhood (ages 9, 11, and 13), perhaps because daughters’ disinhibited eating was lowest at age 5 and increased among all groups from age 5 to 13. Although associations between daughters’ and mothers’ disinhibited eating have been previously reported (55
), relationships between fathers’ and daughters’ have not been evaluated. Both Jacobi et al. (56
) and Cutting et al. (55
) found a stronger association between mothers’ and daughters’ eating behavior than fathers’ and daughters’ eating behavior. These findings reveal that mothers and fathers are both influential in shaping daughters’ patterns of BMI change and that the development of disinhibited eating among girls was distinctly different only among families in which both parents were overweight. These findings are consistent with an additive model of parental influence, with both mothers’ and fathers’ genetic and environmental input contributing to daughters’ patterns of weight gain and the development of disinhibited eating, although perhaps in different ways. Our findings are consistent with relatively extensive findings showing maternal influence on daughters’ eating and weight status (31
); there are very few data regarding fathers’ influence.
Research is needed to determine the mechanisms of intergenerational transmission of eating style from parent to child. This sample was selected to include only families in which daughters were living with both biological families. In such cases, parents both provide genes and shape the environments in which these genetic predispositions may be expressed. For example, there is experimental evidence that overeating can be fostered in children by experience with restrictive feeding environments (49
) and that maternal modeling may be important (55
). As indicated above, there is some evidence that disinhibited overeating has a genetic basis and can serve as a behavioral phenotype for obesity (37
). These findings are consistent with this perspective and suggest how gene environment correlations shape the differential emergence of disinhibited eating among children growing up in families with and without overweight parents. For example, if overweight parents are genetically predisposed to disinhibited eating, and children share those genetic predispositions, parental displays of disinhibited eating can foster the acquisition of disinhibited eating by children.
Although there is evidence for the heritability of disinhibited eating behavior (63
), de Castro et al. (64
) found that 40% of the variance in disinhibited eating behavior was explained by a shared environmental component. Provencher et al. (63
) found that only a small amount of the familial resemblance in eating behavior was caused by genetics; family environment was particularly important for dietary disinhibition. A recent study by Faith et al. (37
) tested the hypothesis that our measure of disinhibited eating, EAH, was a genetic marker for childhood obesity. They found some support for this hypothesis among preschool-aged children, but only in boys and not girls. They concluded that eating in the absence of hunger might be more highly influenced by environmental as opposed to genetic factors. In this study, consistent with Faith et al., we failed to note initial associations between daughters’ disinhibited eating and weight status when girls were age 5, when levels of disinhibited eating were lowest among girls. However, our results reveal that parallels in patterns of change for girls’ BMI and disinhibited eating emerged as development proceeded, providing some evidence for disinhibited eating as a behavioral phenotype.
Study limitations include a sample of primarily middle-income, well-educated, and non-Hispanic white families with daughters, and only families in which daughters were living with both biological parents. This precludes generalizing the findings to boys, to single parent families, or to other ethnic and income groups, including those with overweight prevalence rates that are higher than this sample. To classify parents, we used parental BMI, based on measured heights and weights. We also used BMI as our primary measure of daughter overweight. BMI is not a direct measure of adiposity and may have led to misclassification of some parents; however, such misclassification would tend to reduce the likelihood of obtaining relationships among parental weight status and daughters’ weight gain. Data obtained from DXA on girls’ fat mass corroborated the BMI findings among daughters (data not shown). The use of longitudinal data is a positive feature, as was the inclusion of fathers in the research, because it allowed us to provide some initial information regarding paternal influence on daughters’ developing weight status and eating style during childhood and early adolescence.
In conclusion, although no epidemiologic data are available on the prevalence of overweight specifically among parents in the United States, among 20- to 54-year-old adults, an age range that would include most parents, about two thirds are overweight. These estimates suggest that the majority of children in the United States today are living in families with one or two overweight parents; only a small minority of children are growing up in families with neither parent overweight. These findings suggest that children in families with overweight parents are at elevated risk for obesity and that this demographic pattern may further accelerate the obesity epidemic. These findings indicate that, at least for girls, the effects of parental overweight on weight gain and disinhibited eating seem to be additive; girls growing up in families with at least one overweight parent showed accelerated patterns of weight gain from age 5 to 13 years relative to girls with neither parent overweight and that girls with two overweight parents show even more substantial weight gain over the same period.
The findings of this study corroborate previous research (10
) indicating the elevated risk for childhood obesity conferred by having overweight parents and underscores the importance of developing prevention approaches that target overweight parents with young children. To inform such prevention efforts, research is needed to pinpoint the environmental and behavioral mediators of family resemblances in adiposity. Such efforts would include exploring the feasibility of approaches to prevent the transmission of disinhibited eating from parents to children. One approach could focus on reducing disinhibited overeating behaviors among parents to reduce children’s exposure to parental models of disinhibited overeating. Alternative approaches include providing anticipatory guidance for parents regarding approaches to parenting and child feeding that can promote children’s continued responsiveness to hunger and satiety cues in controlling energy intake and providing alternatives to parents’ use of feeding practices that can foster disinhibited overeating among children (38