Effects of Moderate Intensity Walking on Daily and 3-Hour Dietary Intake

Background: The inter-individual variability in the effectiveness of structured exercise to achieve expected levels of weight loss or maintenance appears to be due in part to individual differences in behavioral responses that increase energy intake; however, the influence of acute exercise on dietary intake following exercise remains incompletely characterized.

Purpose: The aim of this study was to evaluate changes in total day and three hour post-exercise (3HR) dietary intake associated with exercise participation among women.

Methods: Previously sedentary women (n=51, 36.1± 6.8y) participated in an 8 week intervention with the goal of 150 min/week of moderate intensity walking exercise (EX). Participation in EX bouts ≥10 min duration was measured via ActiGraph GT3X+. Dietary intake was measured on randomly selected EX and non-EX days via the National Cancer Institute’s ASA24 program with data of interest being total day energy intake in kcals (KCAL) and macronutrient intake; protein (PRO), fat (FAT), and carbohydrate (CHO).

Results: No significant mean differences in KCAL (13.2 ± 547.6, p>.05) or macronutrient intake (-6.3 ± 136.4; -12.3 ± 289.5; and 46.9 ± 340.3 for PRO, FAT, and CHO respectively, all p>.05) were observed between EX and non-EX days. Larger, but not statistically significant, differences in 3HR KCAL (101.1 ± 561.6, p>.05) and macronutrient intake (7.1 ± 124.3; 16.0 ± 279.6, and 63.0 ± 270.1 for PRO, FAT, and CHO respectively, all p>.05) were reported on EX versus non-EX days. In sub-group analyses, women who exercised in the morning (n=10) and those classified as obese (BMI≥30; n=17) reported the largest increases in KCAL and all macronutrients on EX days although only differences in 3HR PRO were statistically significant (p=.04).

Conclusion: Acute changes in total daily caloric and macronutrient intake in response to exercise appear to be modest. The potential impact of exercise timing and the role of body composition on modifying dietary responses to acute exercise warrant further study.

Supported by NHLBI-1R21HL113742-01