# Academic exam periods and ultra-processed food consumption: evidence from supermarket transactions in a Colombian University

## TL;DR

Exam periods lead to a 12.9% increase in students' purchases of ultra-processed foods, showing stress or time constraints drive unhealthy eating.

## Contribution

This study provides causal evidence using supermarket transaction data to show how academic stress affects food choices.

## Key findings

- Students buy 12.9% more ultra-processed foods during exams compared to non-exam periods.
- The effect is not observed in university staff, indicating it is specific to students.
- Changes in purchases occur before, during, and after exams, showing a temporal pattern.

## Abstract

Academic stress can change eating behavior and often leads to higher consumption of unhealthy foods. This study examines whether exam periods affect students' purchases of ultra-processed foods, using objective purchase data rather than self-reports.

We analyze point-of-sale transaction data from a university supermarket in Colombia. We use a difference-in-differences design. Students are the treatment group and university staff are the control group. We compare ultra-processed food purchases across pre-exam, exam, and post-exam periods.

During exam weeks, students increase their purchases of ultra-processed foods by 12.9 percent relative to non-exam periods, with statistical significance at p < 0.05. No significant changes appear among non-students. The effects vary across time, with changes observed before exams, during exams, and after exams.

The results provide causal evidence that exam-related stress or time constraints increase demand for ready-to-heat, ultra-processed foods. By relying on transaction data, this study overcomes limitations of self-reported measures. The findings highlight clear temporal patterns in stress-related or convenience-driven food choices and suggest relevant implications for campus nutrition policies and stress management interventions in academic settings.