Try eating foods high in fiber and potassium such as bananas, strawberries, etc. Also, many vegetables such as lettuce, celery, carrots,... are almost entirely water and hence while filling you up, won't cause you to gain any weight. You will want to do your best to stay away from high fat foods as they provide 9 calories per gram of fat and are not very filling. Spreading out your meals is a very smart way to trick your body into thinking it is always full and should definitely be implemented. Good luck.