What you should do is eat lots of snacks that don't count against your diet too much. What kind is it? A generic low fat/less calories diet? You should make sure you're eating often enough at the very least. The best diets have you eating 4-5 times a day, especially if you work out a lot. Good snack foods: veggies, nuts, low fat cheese/string cheese, sugar free sweets. Anything with protein or fiber. They will prevent you from going back to your old habits. But at the same time, I feel that if you want a cookie one day, just eat the damn thing. Ignoring cravings too often will lead to binges.
Your body will conserve calories and maintain fat if you are not eating enough during the day. Small, frequent meals is the key. Never let yourself feel hungry. You will be able to control the cravings and amount that you eat if you are not "starving" hungry. Weight loss is one simple equation - you must burn more calories than you eat. Period. Making wise food choices will make losing body fat easier. Work out. You need to burn the calories so getting a work out will help you achieve this. You may need to ramp up your work out or try a different form of exercise if you are not seeing results.
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