Hi there I have been on 800 cals a day strict diet for 2 weeks and i havent lost any weight in fact 1 day and the only day i cheated by having 1 extra pitta bread. Plus a full 1 instead of a half at lunch 3 halves of pitta bread are allowed on it if you choose 3 from your carb allowance i normally have half for breakfast half for dinner and 2 egg sized potatoes at tea now this 1 day as i was extra hungry i ate a full one at lunch and 1 in the. Evening next day id gained a 1lb the one im on is very strict i put myself on it you are only meant to stay on it 3 wks its 800 cals and a. Nhs 1 for pre op bariatric surgery patients. you also take a vitamin im losing nothing when i stick to it im in my 50s 5ft 1inch tall the calories seem to many for my metabolism yet to cut down more id be really hungry.As the diet is not ketogenic and the reccomended cals for my height age etc is higher than 800 if i ate what they said id be 4 stone heavier in no time anyone met up with this