Diet Quality Changes in a 12-Week Web-Based Physical Activity Intervention without Explicit Dietary Guidance

Lifestyle habits seem interconnected and extant studies suggest that a lifestyle-related modification can impact other related behaviors. For instance, interventions targeting physical activity (PA) could potentially impact dietary patterns and quality. Therefore, we hypothesized that a web-based intervention to increase PA would lead to changes in diet quality without explicit dietary guidance. Our aim was to evaluate changes in diet quality, measured by the Healthy Eating Index 2020 (HEI-2020), following a 12-week web-based PA intervention in adults with obesity. The study consisted of secondary analysis of a 12-week pilot randomized controlled trial, wherein participants (N = 82) were randomized to the Physical Activity for The Heart (PATH) intervention group, which included workout videos and virtual coaching, or a wait-list control group. Diet quality was assessed at baseline and post-intervention using the HEI-2020 based on recalls collected through the Automated Self-Administered 24-h recall (ASA-24) system. Baseline characteristics were similar across groups. Both groups showed small improvements in HEI-2020 total scores after 12 wk (PATH: 65.11 vs. Control: 62.24). Stratification by moderate to vigorous physical activities increase (<60 min. vs. ≥60 min.) revealed greater improvements in specific HEI-2020 components in the ≥60 min group, though overall changes remained modest. The PA intervention led to small improvements in certain diet quality components, suggesting potential interconnectedness between PA and dietary habits. However, overall changes in HEI-2020 scores were modest. Future research with larger samples should explore the effects of PA intervention alone vs. combined with dietary guidance on diet quality in adults with obesity.