The aim of this research was to test a theoretical formulation that predicts relations of self-control constructs to health-related behavior. The study was based on a community sample of adolescents and used standardized measures of dietary intake and physical activity. Consistent with previous research [12
] the measured indicators of self-control were normally distributed in the adolescent population, and the latent constructs for self-control represented two distinct domains rather than opposite ends of a single continuum. Results indicated the self-control constructs were related to both dietary and exercise behaviors, controlling for demographics. Independent of effects for self-control, the analysis showed significant effects for gender and ethnicity, with females having less vigorous exercise and minority-group members having less vigorous exercise and a less healthful dietary pattern.
The results showed that planfulness and impulsiveness had different types of relationships to dietary and exercise behaviors. Persons who scored higher on good self-control had more fruit and vegetable intake and less sedentary behavior, as well as having more participation in sports. A different pattern was noted for persons scoring higher on poor self-control, who had more saturated-fat intake and a lower frequency of engaging in vigorous exercise. These results were based on a diverse sample of adolescents and analyses indicated that effects of self-control were not limited to a particular demographic subgroup, as effects of self-control on dietary and physical activity outcomes were found to be comparable across gender and ethnic groups. The finding of different patterns for the two domains of self-control is consistent with research in other areas [12
]. The suggestion is that a higher level of good self-control relates to behaviors that require information seeking, planning, and investment of effort to accomplish, whereas persons who score high on poor self-control are more susceptible to situational pressures and less inclined to resist temptations for undesirable behaviors [11
]. Theoretical papers have outlined dual-process models of adolescent behavior positing a more reasoned/reflective pathway together with a more impulsive/reactive pathway [27
], and these concepts may be useful for understanding processes in the formation of diet and exercise patterns.
The finding of significant effects for self-control in this study indicates that adolescents do have some choice in regard to their diet and exercise so individual characteristics can play a role in shaping patterns of eating and frequency of physical activity, and they may interact with environmental factors. The results suggest directions for further research on health-related behavior in the context of social-cognitive theory [28
]. It is possible that self-control has direct effects on dietary intake and physical activity, not involving any other processes. Research on adolescent substance use, however, suggests that indirect effects should also be considered [11
]. It is possible that developing a higher level of good self-control is associated with greater awareness of vulnerability to health risks and a more reasoned approach to making decisions about diet and exercise [29
]. The component processes underlying a higher level of poor self-control are conducive to a present-oriented perspective in which there is less concern with the future, more inclination to affiliate with teens who are engaging in health risk behaviors [12
], and less motivation to persevere in achieving goals for more healthful behavior [31
]. These kinds of processes may be explored in further research on relations of self-control processes to dietary and physical activity outcomes.
The results of the present study are consistent with national data in showing gender and ethnicity related to diet and exercise patterns [e.g., 32
]. It is recognized that the determinants of dietary intake and physical activity are multifactorial in nature, including variables such as home availability of fruits and vegetables and family support for and modeling of behavior patterns [15
]. In addition, social factors act to promote or create barriers to healthful behavioral patterns [35
], and environmental factors may affect access to shopping and physical activity opportunities [37
]. These kinds of variables may be addressed in efforts to reduce health disparities in the population.
Although relatively simple measures were used to index diet and exercise, the self-control constructs accounted for 5-15% of the variance in the health behavior outcomes controlling for demographics, a contribution that is meaningful from a prevention standpoint in view of the multiple contributions to such behaviors and the fact that self-control characteristics are modifiable. Interventions in clinic and home settings that included components for goal-setting and self-monitoring have shown effects for reducing body-mass index scores [39
], and the present research has suggested problem solving, delay of gratification, self-reinforcement and other cognitive skills as also relevant for diet and exercise patterns. Thus we think in addition to family environment, attention to self-control processes is warranted as an avenue of investigation for programs designed to improve health behaviors in childhood and adolescence.
There are some aspects of this study that could be noted as limitations. Though the sample was diverse in ethnic and socioeconomic characteristics, the study was conducted in one community and the results need to be replicated in other geographic areas. One of the self-control indicators had lower reliability, and while this is compensated by the latent construct approach, longer indicator measures should be tested where feasible. The measures of diet and exercise were relatively simple ones, and further research using more intensive assessments of diet and exercise patterns would be desirable to test effects of self-control on health behaviors. Finally, the design of the present study was cross-sectional, and longitudinal research can be conducted to delineate temporal relations of variables and study possible mediation processes for effects of self-control.