Does The Quality Of Dietary Intake Improve With Regular Exercise?
Houle, Sarah Medicine & Science in Sports & Exercise: July 2020 - Volume 52 - Issue 7S - p 415
Lifestyle-induced reduction in health risk is thought to be the result of improvement in both exercise and eating behaviour. Whether increasing exercise is associated with a corresponding improvement in eating behaviour is unclear.
PURPOSE: To determine if the adoption of exercise consistent with consensus recommendations influences diet quality in previously sedentary adults.
METHODS: Participants were 129 obese (BMI: 33.0 ± 4.5 kg/m2), middle-aged (51.5 ± 7.9 years), sedentary adults (81 females [62.8%]) who were randomly assigned to one of the following 4 groups: i) no-exercise control (n=32), ii) low-amount, low-intensity exercise (LALI) (180 and 300 kcal/ session for women and men, respectively, at 50% of VO2peak) (n=36), iii) high-amount, low-intensity exercise (HALI) (360 and 600 kcal/session, respectively, at 50% of VO2peak) (n=40), iv) high-amount, high-intensity exercise (HAHI) (360 and 600 kcal/session, respectively, at 75% of VO2peak) (n=21). All exercise sessions were supervised. Self-reported daily diet records were assessed using an automated web-based program. The Canadian Healthy Eating Index (C-HEI) was averaged from 3-day diet records obtained at baseline, 8, 16 and 24 weeks. C-HEI is calculated using 8 adequacy (total vegetables and fruit, whole fruit, dark green and orange vegetables, total grain products, whole grains, milk and alternatives, meat and alternatives) and 3 moderation (saturated fats, sodium, other food) components. The components were summed to produce a single score between 0 and 100, with higher scores reflecting greater adherence to 2007 Canada’s Food Guide, and hence better diet quality.
RESULTS: Mean (± standard deviation) C-HEI in all participants at baseline was 58.4 ± 13.4, with no difference between groups (P= 0.40). There was no change in C-HEI at 24 weeks vs baseline in any of the groups assigned to increased amounts of exercise or intensity (p=0.5). Collapsed across all groups, the mean change in C-HEI at 24 weeks was (3.9 ± 16.0).
CONCLUSION: The diet quality of the participants, as reflected by the C-HEI, was poor at baseline and was not improved consequent to the adoption of exercise consistent with consensus recommendations. Contrary to expectations, engaging in a structured exercise program is not paralleled by favorable changes in dietary behaviour.