Your doctor is pretty much right. The idea is: If you eat small portions throughout the day, that will help keep your blood sugar more stable, so you won't be tempted to "pig out" all at one time. Unfortunately, this doesn't always work -- *I* tried it and it seemed like I was constantly focused on when I could eat again. I now, just eat when I'm hungry, but I make sure I eat EVERY time I get hungry and stop eating as soon as I begin to feel full.
Try making small changes to begin with, rather than going to extremes, because if you try to change everything all at once, you most likely won't stick with it. Like drinking water -- a lot of people have trouble with that (including me), so if you normally drink soda or sweetened tea, try replacing one soda/day with a glass of water, then after a few days, replace another soda with a glass of water.
I have the same problem im soooo frustrated talked to my doc and said i have to eat very little portions several times a day drink like soooo much water and work out alot until i get to the weight i want to be at and then i can slow up on the excersizing. I dont know though