Well, lots of raw fruit and veg such as apples, bananas, oranges, carrots, celery and cucumber will do you alot of good and fill you up. If the veg is too bland for you then dip in low fat hummus, which is a lean protein source.
Beans and lentils/peas in general, are high protein and low GI (steady release carbs) so will satisfy a big appetite
Also, nuts and seed smay be high fat but are all good fat and very filling and nutritious, so include 50g of these a day instead of frying and drizzling oils.
Whole grains are steady release, high fibre, and high protein, so will be very important for keeping you full, and energised.
Try not to get stuck in a wheat ruck! Quinoa, brown wholgrain rice, popcorn, barley, and rye are favorites and some people say that they cause less bloating than wheat. All you need to do is boil quinoa for 15 minutes and then dress up with whatever flavours you like.
If you want chocolate, have some dark green and blacks, which is still high calories, but nutritious, and you probably won't want as much to satisfy the choccy craving... OR, make a nice hot chocolate if you want sweet choc: use a cup of soy or rice milk, and a few tbs of cocoa powder, then sweeten, if liked, with agave syrup, or a sweetner tablet.
Good luck!