This project aims to investigate the impact of acute bout of submaximal exercise under different pre-exercise dietary conditions (fasted state versus high carbohydrate breakfast versus high protein breakfast) on postprandial glycaemic, appetite regulation and energy balance.

Participants will be asked to arrive to the laboratory between 08:00 and 9:00 am after not eating for between 12-14 hours i.e. in a fasted state (water intake is permitted and encouraged). Participants will then be given one of three test drinks (i.e., breakfast): 1) water only; 2) high carbohydrate drink; or 3) high protein (whey protein) drink. Each of these drinks will also contain 500 mL of water and artificial sweetener. 2 h after breakfast, participants will then exercise on a treadmill for 45 min followed by a 2-h oral glucose tolerance test (OGTT) and 30 min ad libitum lunch intake. Blood samples, blood pressures and questionnaire (e.g., appetite and mood) will be collected in a regular pattern throughout the trials. Cognitive functions will be tested at baseline, pre-exercise and 2 h post-exercise. Energy balance will be assessed using food diary and an accelerometer for the rest of the day after leaving the laboratory until midnight.

Inclusion Criteria:

• Healthy physical active men (self-reported regular exercise at least 30 min moderate-intensity 3 times per week)
• Aged between 30 to 55 years
• Weight stable for more than 3 months (no change in weight +/- 3%)
• Non-smoker

Exclusion Criteria:

• Personal history of/existing diabetes, cardiovascular disease, metabolic disease or dyslipidaemia
• Taking medications that may influence lipid or carbohydrate metabolism or immune system function
• Women
• Physically inactive

Participants and Researchers will be blinded to the interventions.