Was the doctor a GP? GPs often get a bit beyond themselves and go outside their standard of care, or what the seppos call "scope of practice."
A GP is not qualified to prescribe a diet plan, anymore than they are qualified to perform open thorax surgery, or give a massage, or do rehab after a knee reconstruction. Detailed meal plans are a dietician's job.
Lap band surgery is an abomination. Taking a perfectly healthy organ and deliberately cutting off half or more of its function is just wrong. Cutting your stomach in half because you eat crap food is like cutting half your foot off because you wear shoes too small for you. The organ is fine, what you're putting in it or on it is the problem.
Good luck to the woman who went to PTC, I hope you train hard and eat well. I don't care if your bum is big or small, only if you're healthy - good exercise and good food can achieve that.
Markos isn't a dietician, either, last I heard, but his advice will certainly be better than the advice she has had so far. Bloody hell, there are high school kids who just did nutrition in Home Economics whose advice will be better than that.