Effects of sugar and fiber consumption in minority adolescents and self-tracking as a potential dietary intervention tool

Diets that are characterized by high sugar and low fiber intake are widespread in the United States, and are particularly prevalent among African American and Hispanic adolescents. Sugar consumption may have physiological, psychological, and behavioral effects that reinforce subsequent sugar intake at the detriment of more healthful foods, such as those high in fiber. Examining key acute effects of sugar consumption in overweight minority adolescents may reveal targets for improving dietary interventions. A promising tool that could supplement dietary intervention efforts is self-tracking. However, self-tracking adherence tends to be low and decline over time, so research is needed that provides insights into factors that can promote long-term self-tracking adherence. The objectives of this dissertation were to: 1) investigate the acute impact of high sugar/low fiber (HSLF) versus low sugar/high fiber (LSHF) test meals consumed in a laboratory setting on subsequent ad libitum sugar intake in a sample of overweight minority adolescents, 2) examine the impact of negative mood on hunger ratings during the HSLF and LSHF test meal conditions in the same sample of adolescents, and 3) use a mixed methods approach to explore factors that facilitate self-tracking adherence in a sample of individuals who self-track weight-related behaviors. ❧ Findings from study 1 demonstrated that consumption of HSLF and LSHF test meals had different effects on the amount of ad libitum sugar consumed by overweight minority adolescents in the laboratory setting. Participants consumed an average of 8 more grams of sugar during the ad libitum snack period that was provided after condition-specific breakfast and lunch meals when they were in the LSHF condition compared to when they were in the HSLF condition (p = 0.002). Contrary to the hypotheses, negative mood reported during the snack period did not mediate the relationship between meal condition and ad libitum sugar intake in the LSHF condition. Additionally, the amount of sugar participants reported habitually eating in daily life did not moderate the meal condition-ad libitum sugar intake relationship. However, impulsivity did moderate the relationship; higher impulsivity was associated with higher ad libitum sugar intake in both meal conditions (LSHF: p<0.01; HSLF: p<0.01). These findings suggest that 1) when participants were restricted from eating sugar during the LSHF breakfast and lunch meals, they compensated by eating more sugar when they were later given a choice of foods to eat during the snack period, and 2) higher impulsivity predisposed participants to consume more sugar when they had free access to sugar during the snack periods, regardless of whether they were provided access to sugar or restricted from sugar intake during the breakfast and lunch tests meals. ❧ Study 2 findings demonstrated that negative mood was associated with perceived hunger during both the HSLF and LSHF meal conditions. At the beginning of the in-lab visit for both meal conditions, when participants were in a fasting state, greater negative mood was associated with greater perceived hunger (HSLF: p<0.05; LSHF: p<0.05). Perceived hunger decreased throughout the day during both meal conditions, and negative mood was associated with the change trajectory of perceived hunger during the LSHF condition. Specifically, during the LSHF condition, greater negative mood was associated with a more pronounced decline in perceived hunger throughout the day (p<0.05). Contrary to the hypotheses, habitual total sugar intake did not moderate the relationship between negative mood and perceived hunger. These results demonstrated that negative mood was associated with perceived hunger during the test meal conditions, and that direction of this relationship differed based on whether the relationship was captured in a cross-sectional or repeated measures manner. ❧ The third study of this dissertation used a mixed methods qualitative/quantitative approach to discover factors that contribute to self-tracking adherence. The quantitative component of the study examined how a group of self-trackers differed from a group of non-trackers on key characteristics, and found that the self-tracking group had higher autonomous motivation and higher competence for engaging in healthful dietary and exercise behaviors (motivation dietary: p<0.0001; motivation exercise: p<0.05; competence dietary: p<0.01; competence exercise: p<0.01). The qualitative component of the study used in-depth interviews to gain insights into factors that help adherent self-trackers initiate and maintain a practice of self-tracking weight-related behaviors. Findings provided useful knowledge about strategies that aid self-tracking adherence, including paying attention to immediate feedback from tracking tools and reviewing past self-tracking data to understand goal progress. This first exploratory study of factors that facilitate self-tracking adherence revealed many insights that remain to be tested in future intervention research. ❧ This dissertation makes important contributions to the body of research on the effects of dietary intake in overweight adolescents and to the emerging self-tracking literature. Overall, findings from the three studies that comprise this dissertation demonstrate that sugar-rich, fiber-poor meals can have acute negative effects in overweight minority adolescents, and that self-tracking adherence is modifiable, so it has the potential to be taught to adolescents and utilized to aid dietary behavior change in future interventions.