Acute Effects of Greek Yogurt Consumption on Bone Status Indices Following High-Intensity Interval Exercise in Premenopausal Females with Obesity: A Secondary Analysis from a Randomized Crossover Trial

Chronic inflammation associated with excess adiposity can compromise bone microstructure, increasing fragility and fracture risk. Thus, developing strategies to improve bone health in adults with obesity (OB) is critical, particularly in premenopausal females, to protect bone before menopause. While acute exercise transiently increases bone turnover, beginning with resorption, dairy products containing bone-supporting nutrients may attenuate the bone resorption phase. This secondary analysis assessed the effects of post-exercise Greek yogurt (GY) consumption versus a carbohydrate pudding (CP) on bone status indicator responses in premenopausal females with OB. Using a randomized crossover design, 20 participants (age: 36±5years; BMI: 38.7±7.6kg/m2) completed high-intensity interval exercise (HIIE; 10x1-min cycling intervals at ≥90%HRmax) followed by consumption of GY (247kcal, 14g carbohydrate, 32g protein, 350mg calcium) or isoenergetic CP (247kcal, 62g carbohydrate, 0g protein, 0mg calcium). Trials were separated by 4 weeks. Blood samples were collected pre-exercise (fasted), immediately post-exercise, 1h and 3h postprandially, and 24h post-exercise. Significant time*trial interactions were observed whereby osteoprotegerin (OPG) and osteocalcin (OC) were higher at 1h (p<0.001) and 3h (p=0.03) postprandially, respectively, and parathyroid hormone (PTH) was lower at both 1h (p<0.001) and 3h postprandially (p=0.001) in GY versus CP. Net incremental area under the curve analysis also revealed a significant elevation in PTH across the CP trial compared to GY. Therefore, GY consumption following HIIE may support a more favourable bone turnover response by attenuating resorption (PTH), maintaining bone formation (OC), and supporting anti-resorptive responses (OPG) compared with CP during the 1-3h postprandial period in premenopausal females with OB.