I couldn't care less whether you think my post is rude, feel free to use the ignore option. You miss the point 21 pounds weight loss would have a small impact on the patients safety if emergency surgery carried out by a general surgeon rather than a specialist bariatric team who might not be available, was required not the huge one you claim.
The surgical team gave the OP an eating plan that she admittedly failed to follow hence the telling off by the specialist nurse, if she was "allowed" to ignore the plan why did the specialist take her to task? (Don't remember reading that you are a qualified bariatric specialist) and you telling her and potentially other patients who read this drivel that she did the right thing is frankly irresponsible and beggars belief.
The OP got away with going against her surgeon's advice, well done her, others might not be so lucky and your claim that we know our bodies post op better than the professionals during the healing process is simply ridiculous and dangerous. My advice would be follow your surgeons advice and you will be OK, stray from that and you put your safety at risk.