I added steel cut oats for breakfast and that was the only thing I added for about a week. I knew I wasn't going to be tempted to eat more than one serving and I was really missing hot cereal in the mornings.
I added 1 fruit the following week, as a snack. I had blueberries or half an apple with yogurt and I think it was nearly a month before I ate fruit by itself because I was worried I wouldn't be satisfied with just one serving.
Even though it's allowed at this point, I rarely have more than the oatmeal and 1 or 2 servings of fruit each day. I had a hard time getting enough veggies in when I was eating more grains and it's those 4 and 1/2 cups of veggies every day that seem to keep my scale moving in the right direction!