broccoli is somewhere around 50 cals per cup depending on if you're talking frozen or fresh or cooked. add a little bit of cheese and you're getting a cup of food for less than 100 cals. and personally, since i find potatoes to be the most filling food ever, pop that broccoli and cheese on a 100 gram potato that you bake and you're adding less than 100 cals but fiber and protein. that will keep me full for a few hours.
spinach and cauliflower are also low cal and have volume.
i also make a lot of lentil vegetable curries. it's a great way to clean out the fridge and tends to be less than 200 cals a cup when you toss in zucchini, broccoli, carrots, cauliflower, mushrooms, peppers, onion, and dark green leafies. it also freezes well. and if i want to make it even more filling, i'll mash some potatoes with greens and serve that under the curry. lots of bulk for not a lot of calories.
-google first. ask questions later.