Exercising in the fasted state results in greater fat oxidation during exercise and results in decreased caloric intake in the meals after exercise. However, the studies that examine fasted vs. fed exercise utilize a carbohydrate-based breakfast, which can increase blood glucose and insulin concentrations, which is considered a negative consequence. A protein breakfast, which can increase satiety and rest of day energy intake could also increase resting energy expenditure as well as fat oxidation during exercise. However, comparisons between fasting exercise and pre-exercise breakfast macronutrient intake (i.e., carbohydrate vs. protein) have not been made. Therefore the purpose of this study is to investigate if eating breakfast and the composition of this breakfast before exercise has an effect on the food eaten throughout the rest of the day.

Inclusion Criteria:

• 18-45 years old
• regularly participate in exercise for at least 150 min per week
• run at least 3 days per week for 30 minutes
• able to complete a VO2max test
• able to exercise for 45 min moderate intensity exercise at one time without breaks

Exclusion Criteria:

• not participating in structured exercise of 150 min/week for the past 6 months
• not running at least 3 days per week for 30 minutes
• not attaining a VO2max of 50 ml/kg/min (60th percentile fitness classification according to the American College of Sports Medicine)
• currently smoke or quit smoking less than one year ago.
• diagnosed with or are being treated for a cardiovascular disease, high blood pressure, fibromyalgia, irritable bowel syndrome or a metabolic disorder such as diabetes, thyroid disorder, or high cholesterol.
• food allergies or sensitivities.
• not willing to have blood drawn on 4 occasions during each trial (16 total times)