Having read most of the comments here, I'm amazed anyone can stick to a diet of shakes! There are alternatives also backed up by proper research. The Blood Sugar Diet proposed by Dr Michael Mosely also sticks to 800 Calories but ALL proper food. Recipes are varied (and you can invent your own) and taste fantastic. I have recently been diagnosed diabetic and am choosing, with my GP's authorisation, not to go on metformin but follow this diet. If u want extra support there is an online programme with individual medical and other support. I thought I might join, but the diet is so easy to stick to that I don't feel the need (certainly for now). My sister (with whom I live, and who doesn't have diabetes) are eating the same meals most of the time and planning to change permanently to this way of eating. With middle eastern turkey and apricot burgers and chicken wrapped in pancetta, or fish curry, stir fry....what's not to like?