Date of Award:

12-2026

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Abiodun T. Atoloye

Committee

Abiodun T. Atoloye

Committee

Mateja Savoie-Roskos

Committee

Stephan Van Vliet

Committee

Cris Meier

Committee

J. Scott Crapo

Abstract

Adolescence is a period of rapid growth and development during which good nutrition is especially important for long-term health. However, many adolescents in the United States consume large amounts of ultra-processed foods, including packaged snacks, sugary drinks, and fast food. This dissertation used nationally representative data from the National Health and Nutrition Examination Survey (NHANES) 2017–2020 to examine micronutrient intake, ultra-processed food consumption, food-related behaviors, and metabolic health among U.S. adolescents.

The first part of the study examined usual nutrient intake and micronutrient adequacy. Overall micronutrient adequacy was high at 96%. However, important dietary concerns remained. Many adolescents had low intakes of calcium and magnesium and consumed high amounts of saturated fat, added sugars, and sodium. Adolescents who used dietary supplements had higher intakes of several vitamins and minerals, but supplement use did not eliminate all nutrient shortfalls. Ultra-processed foods contributed about two-thirds of total daily energy intake, with differences observed across demographic groups.

The second part examined whether food-related behaviors were associated with ultra-processed food consumption and micronutrient adequacy. More frequent fast-food consumption was associated with a higher estimated share of energy from ultra-processed foods, although this relationship was not statistically conclusive. More frequent snacking was associated with slightly higher overall micronutrient adequacy. However, the study did not assess the nutritional quality of individual snacks, so this finding should not be interpreted to mean that more frequent snacking is necessarily healthier. Other behaviors, including nutrition label use, calorie information use, and food-place exposure, showed limited or inconsistent associations with dietary outcomes.

The final part examined whether ultra-processed food consumption and micronutrient adequacy helped explain relationships between food-related behaviors and metabolic syndrome, a cluster of risk factors associated with future diabetes and cardiovascular disease. Metabolic syndrome affected about 7% of adolescents in the analytic sample. Neither ultra-processed food consumption nor overall micronutrient adequacy was clearly associated with metabolic syndrome, and the statistical models did not identify significant indirect pathways linking the food-related behaviors examined with metabolic syndrome through these dietary measures.

Overall, the findings show that adolescent diet quality is multidimensional. High overall micronutrient adequacy can coexist with high consumption of ultra-processed foods and other unfavorable dietary characteristics. Strategies to improve adolescent nutrition should therefore extend beyond addressing individual nutrient shortfalls and promote dietary patterns that increase nutrient-dense foods while reducing excessive intake of ultra-processed foods, added sugars, saturated fat, and sodium. Nutrition interventions should also consider the specific foods adolescents consume during common eating behaviors, such as snacking and fast-food consumption, rather than focusing only on how frequently these behaviors occur. Future research should examine specific types of ultra-processed foods and snacks and use longitudinal studies to better understand how adolescent dietary patterns and food-related behaviors influence metabolic health over time.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .