Prolonged sitting has been shown to impair metabolism and vascular function. The overall purpose of this study is to determine if breaking up prolonged (9 hours) of sitting with brief (~20 second) stair climbing exercise "snacks" can improve markers of metabolic control and vascular health in healthy young male participants and in males or females with overweight/obesity who are at risk of insulin resistance. An additional purpose is to determine if saliva insulin can be used as a valid indicator of blood insulin when measured throughout the day in sedentary and active conditions and when diets with different amounts of carbohydrates are consumed.

Lean Group Inclusion Criteria:

Non-smoking

Lean Group Exclusion Criteria:

Diagnosed with diabetes or prediabetes (fasting blood sugar more than 6.0 mmol/l) or any other chronic condition that may impact glucose or insulin levels.

BMI is over 25 kg/m2 Take medications which may affect glucose and insulin levels Allergic to eggs. Smoker Competitive or serious endurance athlete.

Overweight/Obese Group Inclusion Criteria:

Elevated waist circumference (>102 cm for male and >88 cm for female)

Overweight/Obese Group Exclusion Criteria:

Diagnosed with diabetes (fasting blood sugar more than 7.0 mmol/l) Take medications which may affect glucose and insulin levels Allergic to eggs. Smoker Competitive or serious endurance athlete.

We will share individual patient data (de-identified) with researchers upon request.

It is not possible to mask the exercise or diet interventions.