Date of Award
1-1-2025
Degree Type
Dissertation
Degree Name
Doctor of Philosophy in Health Sciences
Specialization
Nutrition
Department
Nutrition
First Advisor
Kathleen J. Melanson
Second Advisor
Ingrid Lofgren
Abstract
Ultra-processed food (UPF) intake has been positively associated with adverse health outcomes and poor diet quality (DQ). UPFs tend to be of lower nutritional quality (NQ) than less processed foods, though NQ varies widely within each category of food processing. Young adults are the highest consumers of UPF, but UPF intake and related behaviors have not been examined in college students, a key subset of young adults. UPF overconsumption at meals has been proposed as a mechanism for the association between UPF intake, poor DQ, and adverse health outcomes, though no existing studies have considered NQ. Further, consumer understanding of UPFs is poor, and the scientific community lacks a consensus definition for UPFs. The overarching aim of this research is to examine relationships between UPF intake, diet and nutritional quality, ingestive behaviors, and how young adults understand the concept of UPFs. The first chapter examines associations between UPF intake and DQ in young adult college students. Dietary data were collected using the online Diet History Questionnaires II and III. The Healthy Eating Index 2020 (HEI-2020) adult score assessed DQ, and NOVA classification was used to identify UPFs. A statistically significant inverse association was found between %EI from UPF and HEI-2020 total scores (F=340.72, p< 0.001, R2=0.27), all HEI adequacy scores except whole grains (not significant) and dairy (weak positive association), and for saturated fat, refined grains, and sodium scores. When participants were sorted into groups based on DQ and UPF intake, a third of participants had either low UPF intake and low DQ or high UPF intake and high DQ. These findings suggest that while addressing UPF intake in college students may improve DQ, interventions should also address other drivers of poor DQ. The second chapter examines differences in energy intake, ingestive behaviors, and subjective palatability in 40 young adults fed each of three meals: Meal 1) Non-UPF high NQ, Meal 2) UPF high NQ, and Meal 3) UPF low NQ. In meals matched for energy, macronutrients, and flavor profiles and consisting of similar foods, EI did not differ between Meal 1 (585.7 kcal ±163) and 2 (609.7 kcal ±151.8) but was significantly higher for both than Meal 3 (503.0 kcal ±164.1). Meal 1 showed higher palatability ratings, with a higher composite hedonic score (CHS) (65.3 ±22.9 mm) compared to Meal 3 (45.4 ±20.9 mm). Energy intake rate (EIR, kcal/min) was higher for Meal 2 (67.7 ±23.1 kcal/min) than Meals 1 (54.1 ±18.4 kcal/min) and 3 (50.1 ±15.1 kcal/min). Hunger and desire to eat were higher for Meal 3 than Meal 1, with no differences observed for satiety, satiating efficiency, eating time (ET, min), eating rate (ER, g/min), and rest-of-day EI. The study also found that palatability may drive EI and some ingestive behaviors; CHS was positively associated with meal EI (F=11.93, p< 0.01, R2=0.23), ET (F=3.41, p=0.02, R2=0.08), but not ER or EIR. These findings suggest that palatability may be a more important driver of EI than meal processing level, and that not all UPFs may be hyper-palatable. The third chapter explores how young adults define, identify, and conceptualize UPFs. In a mixed-methods survey of young adults (18-39 years) living in the US for > 1 year, respondents defined UPF, identified whether 24 foods were UPF or not using images with front and back of package information, and answered demographic questions. Foods included a high NQ non-UPF, low NQ non-UPF, high NQ UPF, and low NQ UPF item in each of six food groups: fruits, vegetables, dairy, grains, protein, and snacks/sweets. The 422 respondents identified 30 concepts to define UPF. The top concepts were food containing additives, preservatives, colors/dyes, or natural or artificial flavors (N=105), containing non-natural/artificial ingredients or food (N=98), being highly processed/processed in multiple steps (N=95), being altered, manipulated, or modified (N=87), and having low nutritional value/nutrients removed (N=75). The mean score was 16.0 ±3.6 (67%) foods. The findings from this work suggest that the relationship between UPF and DQ and UPF and eating behaviors is complex. While UPF is associated with poor DQ, a third of individuals did not fit that pattern. Subjective palatability, and not food processing, may be a more important driver of EI and other ingestive behaviors, but more research is needed using different mealtimes and flavor profiles. A wide range of concepts were used to define UPF among young adults in the US, and they performed poorly at identifying UPFs. Scientific consensus about a definition is also lacking. Before recommendations can be made about UPFs, a clear definition needs to be established by scientists and nutrition experts, and more research is needed to understand the mechanisms underlying associations between UPF, dietary patterns, and health outcomes.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Larcom, Alexandra Black, "ULTRA-PROCESSED FOOD INTAKE AND DIETARY INTAKE BEHAVIORS IN YOUNG ADULTS" (2025). Open Access Dissertations. Paper 4458.
https://digitalcommons.uri.edu/oa_diss/4458