Overweight/obesity is, in part, etiologically underpinned by a pro-weight gain imbalance in the energy expenditure equation – total daily energy intake (TDEI) exceeds total daily energy expenditure (TDEE). Physical activity (PA) is commonly incorporated into weight loss programs to increase TDEE. The influence of PA on TDEI, however, remains controversial. PURPOSE: To determine whether macronutrient and kilocalorie intake are influenced by a 16-week internet-based physical activity behavior change program (IPAP), which did not directly manipulate dietary habits, in sedentary, overweight/obese, young and middle-aged adults. METHODS: Participants (N=28) were 28 young and middle-aged (44.0+9.6 years) sedentary (<90 minutes of PA/week) and overweight/obese (BMI = 32.2+1.2 kg/m2) adults who were randomized to either the delayed intent-to-treat control condition (N=15) or the 16-week IPAP (N=13). At baseline and after 16-weeks, PA (steps/day), body composition (BMI, waist circumference, % body fat), aerobic fitness, and self-report 3-day food diaries were measured. RESULTS: PA significantly increased in the IPAP group (6611+458 vs. 8053+458 steps/day; P<0.05) but not in the control group (7430+488 vs. 7976+488 steps/day). In the IPAP group, total grams of protein decreased (82+5 to 65+5 g; P<0.05) and percentage of total kilocalories from protein increased (16+1 to 18+1%; P<0.05) and neither changed in the control group. For fat and carbohydrate in the IPAP group, total grams consumed decreased 23% and 25%, respectively (P<0.05), but their contribution to total kilocalorie intake remained similar. There were no changes in the control group for any macronutrients. CONCLUSIONS: A 16-week internet-based physical activity behavior change program that did not directly attempt to modify dietary/eating habits changed macronutrient consumption. The observed reduction in TDEI (kilocalories consumed) combined with the increase in PA would suggest that this internet-based PA behavior change program may be an effective weight loss strategy due to its pro-weight loss influence on both TDEI and TDEE.
Support: NIH Grant # P20 RR016474
Learner Objective: Attendees will be able to describe the relationship between physical activity level and dietary intake among sedentary, overweight/obese, young/middle-aged adults.
Learner Objective: Attendees will be able to list changes in macronutrient intake among intervention participants.