Once you have lost as much weight as you want to lose, and you did so on the 2000-calorie plan, how many portions should you add and in what categories? I realize that there might be some experimentation required but I don't want to go too far the other way and find myself putting weight back on that I lost. Personally, I would love to add grains as they're my favorite, but since I already get eight portions of them I don't know if it's the right food group to supplement.

First, congratulations on your successful weight loss! Now that you're maintaining, you can start adding food. I suggest you add one Vegetable and one Grain - preferably a whole grain. You're right that some experimentation may be necessary. Be careful to monitor your weight so you catch any gain quickly. And keep up with your exercise program. The combination of eating wholesome foods and getting plenty of exercise will keep you at your desired weight.