A study to assess a low volume meal test and a very low calorie diet in obese patients with type 2 diabetes, for the future study of bariatric surgery.

12 participants will be recruited. The study comprises 2 sub studies (study 1 and study 2) and the same 12 participants will undertake both studies. For study 1, participants will be asked to attend our research centre on two separate days (within 7 days of eachother) where a liquid meal test will be performed. This involves the consumption by the participant of a liquid meal (similar to yoghurt in consistency, TWOCAL HN, Abbots nutrition, fat 39.4%, carbohydrate 43%, protein 16.8%, 2 calories/ml) within 10 minutes, and the collection of blood samples immediately before and then at 10,20,30,60,90,120,150, and 180 minutes after the drink is consumed. The volume of the liquid meal will differ between the 2 days (200ml and 50ml), and participants will be randomised as to which of the liquid meal volumes used in this study they undertake first. Study 2 will commence immediately after completion of the second liquid meal test for study 1, and involves participants adhering to a very low calorie diet for 4 days. Participants will be asked to consume no food or drink (with the exception of water) for the 96 hour period from the consumption of the liquid meal through to 8am on study day 6. They will be asked to attend our research unit daily during this time (study days 3-6) for an assessment (including a blood test) and the intravenous administration of 2000ml of dextrose solution (providing 340 calories). At 8am on study day 6 a third liquid meal test will be performed as above before the study is completed. The volume of the meal on consumed by each participant on study day 6 will be the same as taken on study day 2. Adherence to the intervention will be monitored through a daily interview and assessment.