 Ten patients in each group different from those taking part in the meal studies will undergo measurements of hepatic glucose outputinsulin resistance through euglycaemic hyperinsulinaemic clamps Metabolic Study. To ensure that acute caloric restriction does not affect insulin sensitivity, patients will be on a low calorie liquid diet for 4-14 days and 3-7 days after intervention to ensure that their weight is stable throughout the study. This diet is nutritious and contains all appropriate macronutrients. Such diets are frequently used as part of pre-obesity interventions to reduce weight and risk. Patients will provide the investigators with a detailed food diary of their food consumption for this period. 