Keep Up The Good Work: Does Enrolling In An Exercise Program Influence Other Behaviors?

Many agencies promote a healthy “lifestyle” but this comprehensive vision of wellness contrasts with interventions targeting specific health behaviors. However, initiation of a new health behavior could promote, consciously or unconsciously, the modification of a second health behavior. PURPOSE: To investigate if participation in an exercise program promotes spontaneous dietary modification. METHODS: Ninety-eight healthy, sedentary adults (53% female, aged 31.4±6.1 years; baseline BMI 25.0±3.9) were randomized to either 12 weeks of aerobic exercise training (n=44) - 4 days/week for 45 min at an intensity of 80~85% of maximal heart rate followed by 4 week deconditioning - or wait list control (n=54). A Food Frequency Questionnaire was administered at baseline and weeks 12 and 16, to derive caloric intake (Kcal), Alternate Mediterranean Diet Index (aMed), and Macronutrients (Protein, Fat, Carbohydrate) intake. Repeated measures tested treatment, session, and their interaction as predictors with diet measure (Kcal, aMed, Protein, Fat, or Carbohydrate) at Wk12 and Wk16 as the response variables. All models were adjusted for the baseline value of the response variable and were repeated adjusting for gender. RESULTS: Both the exercise (Ex) and the waitlist (WL) groups significantly decreased, from baseline to week 16, mean caloric intake (Ex: Δ=-232.43cal, p.65). CONCLUSIONS: Despite this intervention’s singular focus on aerobic training, both groups showed a marked reduction in KCal and Macronutrients. Sedentary participants willing to enroll in an exercise study may already be in the action stage of behavior change and may independently elect to change dietary behavior to improve overall wellness. Future studies should investigate what psychological triggers lead to a behavioral “spillover” and if the degree of engagement in the primary behavior could predict the magnitude of the “spillover”.