Unbelievably insensitive! Not everyone is tiny and it's not as easy or simple to lose weight as some people may think. What a horrible attitude for a doctor to have. Many years ago, when I was very sick, a doctor asked if I had lost my appetite at all. When I said, 'A little', he said something like, 'Well, you could lose it a bit more.' I wasn't even that overweight at the time, but I will NEVER forget the rudeness of that doctor. I could tell he was in a cranky mood, and the stupid thing was, that I think he was more overweight than I was!
As for vitamin pills. I have read that it is not always good to be taking multi-vitamins, as you can end up overdosing on some. They should not be necessary for a healthy person with a varied diet.
That doctor was totally out of order. Just try to forget the insults and look forward to the future.