Among children at high risk for adult obesity, we found that reported binge eating and dieting attempts predicted increases in body fat mass. Neither depressive symptoms nor disturbed eating attitudes contributed significantly to body fat mass gain.
Our findings are notable because they are the first to examine psychological predictors of changes in body fat mass, as opposed to BMI. DXA is a highly accurate method for measuring body fat mass.33–35
Unlike BMI assessments, it allows for the examination of body fatness, exclusive of muscle mass and other organ weights that contribute to BMI. Particularly during adolescence, when gains in both muscle and bone mass can be substantial, changes in BMI may not directly reflect changes in fat mass.
The finding that children who reported dieting experienced greater fat mass growth supports 3 prior investigations that found self-labeled dieting to be a significant predictor of increased body mass among cohorts of adolescents.5,8,9
A number of hypotheses may account for this seemingly contradictory finding. First, dieting might not have been successful; restrictive diets are rarely maintained over a period of time necessary to lose substantial weight,36
and self-reported caloric intake is frequently inconsistent with actual intake.37–40
Second, successful dietary restriction might trigger compensatory overeating,41
contributing to an increased trajectory of weight gain. Last, and perhaps most likely, repeated dieting attempts before adolescence may reflect efforts by children and their parents to prevent the onset or worsening of obesity among children with unusually rapid, unremitting, weight gain. Multiple childhood dieting efforts would then be a marker for extreme susceptibility for weight gain.
Three previous prospective studies reported that binge eating was associated with gains in BMI over 2 to 4 years among adolescent girls8,10
whereas 1 study of adolescent girls did not find binge eating to predict obesity onset.5
Two studies by Stice et al8,10
are of note because both evaluations used measured (rather than self-reported) BMI. Consistent with most previous studies, the presence of binge eating was associated with greater fat gain in our sample.
In contrast to some studies that reported that depression in childhood3
may predict weight gain, we did not find childhood depressive symptoms to be a significant independent predictor of changes in fat mass. Pine et al3
reported that children and adolescents with major depression had a twofold increased relative risk of reporting they were overweight as adults, and 3 other studies2,4,5
found that adolescents who reported depressed mood at baseline had greater increases in BMI 1 to 5 years later. The lack of relationship between depressive symptoms and weight changes in the present study might be a consequence of the age and psychological profile of our sample. Many subjects had not initiated puberty (when depression often manifests), and few children met criteria for clinical depression. It is possible that depressive symptoms, and perhaps other psychological variables, are more potent predictors of fat gain among older children. Moreover, our lack of findings may be attributable to the use of a questionnaire to assess depressive symptoms. Although the Children’s Depression Inventory is a well-validated and widely used questionnaire, 3 of the 4 prior studies that found a relationship between depression and weight gain used interview methods to assess depressive symptoms.3–5
In the present investigation, when measures of disturbed eating behaviors were also studied, depressive symptoms no longer served as a salient predictor of fat gain among children at high risk for obesity.
Limitations of the current study include the relatively small sample and the reliance on questionnaires, rather than clinical interviews, for assessment of psychological and behavioral variables. Also of note, subjects were recruited purposely either to be overweight or to be at high risk for overweight by virtue of having ≥1 overweight parent. Therefore, these findings may not be generalizable to children who are not at similar increased risk for adult obesity. Because one half of our sample was already overweight at the first assessment, our results may be most reflective of outcomes among overweight children. However, the sample is representative of a population in urgent need of intervention. Children in our sample gained almost 16 pounds per year, ~2.5 times the expected weight gain for children growing at the 50th percentile.12
Finally, although a non–treatment-seeking sample was recruited, families willing to participate in longitudinal studies may differ from those in the general population. Strengths of this investigation include the repeated measurement of body fat mass with a criterion method, the young age of participants at their initial visits, and the inclusion of measures of disturbed eating attitudes and behaviors as well as depressive symptoms.
Among children at high risk for adult obesity, those reporting dieting attempts and binge eating have greater gains in body fat mass during middle childhood. Studies evaluating the efficacy of interventions targeting disordered eating and dieting behaviors among children at high risk for obesity may lead to more-effective approaches for prevention of inappropriate weight gain.