Low calorie meals and foods?

i want to make a big turn around and eat better.
so far im aware of soups, crackers (ryvita etc) fruit and veg.
im after some cooked meals that are probaby veg based that are low calorie
and what is the best low calorie things to eat such as breads, butters, milks, sandwhich fillers, drinks. im after healthy pure foods too, no proccessed rubbish. just need some ideas
etc etc. no im not vegetarian either lol