This study will analyze the effects of Greek yogurt consumption and an 12 week exercise intervention on muscle size, body composition and bone health in untrained, university-aged males.

Introduction: Previous research has shown the effectiveness of dairy milk and whey protein on increasing muscle size, optimizing body composition and increasing strength in adult males. However, evidence on the use of high protein/Greek yogurt on muscle size, body composition and bone health is limited in this population. Yogurt contains similar muscle and bone supporting nutrients as milk, yet it offers a host of additional benefits including; increased satiety, probiotic cultures, greater stability, increased variety, more affordable and versatile features such as acting as a vehicle for consumption of other healthful foods. The proposed research will investigate the use of Greek yogurt as an effective post-exercise food to promote healthy body composition and bone health changes in young adult males.

Design: Parallel, randomized controlled trial.

Participants: 30 (n=15 YOG, n=15 PLA) healthy, untrained university-aged males.

Methods: Subjects will undergo a 12-week resistance and plyometric training program (exercising 3 days/week). The YOG group will consume a 200g dose (pro= 20g, carbs= 8 grams, ~110 kcals) of plain 0% Greek yogurt, while the PLA group will consume an isoenergetic, protein-void beverage comprised mainly of maltodextrin (pro= 0g, carbs= 26g, ~110 kcals). Each group will consume 3 doses per day (immediately and 1 hour post-exercise, and bedtime). Markers of bone health (CTx and P1NP) will be taken at baseline, 1 week and 12 weeks to determine acute and total changes. Muscle size, body composition, strength, vertical jump height and nutritional diaries will be measured pre and post intervention and habitual diet maintenance will be encouraged throughout the intervention.

Anticipated Results: It is hypothesized that each group will undergo positive changes in the aforementioned measures, however due to the increase in protein and calcium consumption, the yogurt group is predicted to have significantly greater increases in these variables than the placebo group.

Inclusion Criteria:

• Male
• Age 18-25 years
• Normal BMI (18.5-24.9) kg/m2
• Have not participated in a resistance training program (of resistance exercise at least 2x/week or more) in the last 6 months
• Healthy and not taking any medication affecting muscle or bone
• Not supplementing with vitamins/ minerals or protein
• Speak and understand English
• No dairy allergy or lactose intolerance

Participants will be randomly selected to the yogurt group or a placebo group. Although participants within the yogurt group will be aware that they are consuming yogurt, the placebo group will not be aware of the contents of the placebo supplement.