Date of Award

2026

Document Type

Honors Thesis (Open Access)

Department

Colby College. Economics Dept.

Advisor(s)

Benjamin Scharadin

Second Advisor

Erin Giffin

Abstract

Ultra-processed foods now comprise the majority of the U.S. food supply and have been directly associated with 32 chronic diseases including obesity, cardiovascular disease, cancer, and diabetes. Current classification systems such as NOVA provide a useful framework for identifying food processing, but rely on broad and subjective categorizations that may not capture the mechanisms most closely associated with promoting persistent overconsumption. In particular, existing classification systems remain limited in their ability to evaluate addiction-like behaviors associated with highly processed foods, including persistent purchasing patterns, reinforcement effects, and substitution responses. This paper introduces the Ultra-Processed Food Intensity (UPFI) index, an objective, continuous, and operational score that evaluates foods based on their under- lying mechanisms linked to overconsumption, including energy density, reward density, satiety support, and available carbohydrate density. Using nearly 67 million household purchase observations from household-level UPC scanner data merged with USDA FoodData Central nutrient data, we show that UPFI captures substantial heterogeneity within NOVA categories and more closely aligns with nutritional characteristics associated with overconsumption than NOVA alone. Persistence analysis, difference-in-differences, and demand-system estimates further show that higher UPFI foods exhibit persistent purchasing behavior, causal substitution following price shocks on staple goods, and distinct substitution patterns. These findings suggest that the objective and continuous processing measure of UPFI may provide a more operational system for policy implementation and nutrition guidance than existing categorical systems.

Keywords

Ultra-processed food, Food demand, Habit formation, Nutrition policy, Overconsumption, Food addiction

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