Type 2 diabetes results from a combination of peripheral insulin resistance and beta-cell dysfunction, and manifests as fasting and postprandial hyperglycemia. In Singapore, despite the relatively low prevalence of overweight and obesity, the prevalence of type 2 diabetes is disproportionately high and is expected to double in the near future. This indicates that insulin resistance and beta-cell dysfunction are widely prevalent even among individuals who are not overweight or obese. Still, weight loss induced by a variety of ways (calorie restriction, exercise, surgery, etc.) is considered the cornerstone of diabetes treatment. This underscores the importance of negative energy balance in improving metabolic function. In fact, negative energy balance induced by calorie restriction can improve metabolic function acutely, i.e. within 1-2 days and before any weight loss occurs. Likewise, negative energy balance induced by a single session of aerobic exercise improves metabolic function over the next few days. However, the magnitude of negative energy balance that needs to be achieved in order to improve metabolic function, as well as possible dose-response relationships, are not known. Furthermore, the comparative efficacy of calorie restriction vs. exercise in improving metabolic function has never been directly assessed.