if you hit a plateau, you need to change things up. Just like with exercise you need variety to shock your body into getting over a plateau. The question is how can you "shock your body with diet? Eating is the most important part of weight loss. But this would depend on the quality of foods you eat, and the timing. I don't know the details of your diet, but just some guidelines:
1. eat 4-6 small meals a day. This increases metabolism
2. limit your sugar! - Juice, sodas and flavored drinks in particular. If you can't eliminate them, then at least reduce the amount.
3. Limit starchy foods such as rice, pasta beans. Don't eat them too much for dinner.
4. Make sure you have a big breakfast!!!! You can eat your starch in breakfast or even lunch, but lay off them after that.
5. Stay away from "fat free" foods, they are usually loaded with sugar