# Mixed-effects location scale modeling of stress and contextual factors on overeating: a real-world observational study

## TL;DR

This study explores how stress and other factors influence overeating in people with obesity using real-world data collected over 14 days.

## Contribution

The study introduces a mixed-effects location scale model to analyze both between- and within-subject factors affecting caloric intake.

## Key findings

- Stress was associated with higher caloric intake on average, with high consistency across individuals.
- Participants consumed fewer calories when stressed and not at home.
- Multiple psychological and contextual factors were significantly linked to overeating.

## Abstract

The objective of our 14-day technology-supported free-living study was to assess how psychological, environmental, and social factors affect overeating among participants with obesity.

We recruited 47 adults with obesity (BMI ≥ 30 kg/m2), who collectively logged 2004 meals, wore and used study devices for meal verification, and completed daily food recalls administered by dietitians. Participants reported on stress, affect, hunger, and meal contexts through Ecological Momentary Assessments (EMA). To explore the factors influencing caloric intake per meal, we employed a two-level mixed-effects location scale model, capturing both between-subject (BS) and within-subject (WS) factors based on the EMA data. This is a secondary analysis of the SenseWhy study, focusing on the association between stress and intake.

Our analysis identified six BS factors (e.g., stress, perception of overeating, restaurant food, later meals, pleasure-seeking meal) and ten WS factors (e.g., biological hunger, perceived overeating, uncontrolled eating, social eating, restaurant food, snacks) to be significantly associated with caloric intake. Notably, participants who were more stressed, on average, consumed more calories (0.74; p = 0.002) with high consistency (−0.7; p = 0.048) between individuals. When stressed and not at home, participants consumed less calories (−0.62; p = 0.0043).

Conventional strategies for managing stress-related overeating fall short. Effectively addressing overeating requires an understanding of both psychological and contextual factors.