The doctor is right, reducing fat is systemic, not local. If a abdominal muscle training video tells you that you will lose your stomach if you only practice this, it must be exaggerated. Think about it, just practice this part, don't do aerobics, don't control overeating. The abdominal muscles will definitely be strengthened, but the oil outside the abdominal muscles is still so thick that even the best abdominal muscles can't be shown.
So, if you're still on a diet, go ahead. When you are reduced to normal size, you can increase your strength training accordingly. One is to maintain a good metabolism, and the other is to make your body lines look better.