Well there could be lots of things going on here. Certainly a bit of protein does help. But i am very pro eating complex carbohydrates and keeping up with your vegetables and fruit. And keeping your diet varied and full of good tasting but healthy foods. Low salt and low fat and no sugar. I think those latter things make your blood sugar levels spike which seems to cause hunger.
Learn about the glycaemic index GI. And learn what foods have low GI.
Lots of people round here seem to eat lots of protein and very little vegetables. Its not a good diet. I see you are off to a good start with the vegetables. Don't stop doing that. Try to eat two cups of cooked vegetables a day at least.
Without knowing your weight and where you've been to get to this point, its just hard to say what's going on. I mean if you are used to eating a great deal of food and then cut suddenly to this amount, its not odd that you feel hungry. And i don't really understand calories too well. I am a little more familiar with kilojoules.
Is your lifestyle boring. I feel hungry or at least want to eat when i am bored or work in an office. When you lead a physically active lifestyle you don't feel hungry so often. Its easier to wait for mealtimes before you need to eat.
Not only meat is protein. There is also protein in milk, yoghurt, lentils, beans, and vegetables though of course not total protein. Though people are suggesting that the high protein foods are more satiating. I think its true but i think that mainly counts for how you feel at the end of a meal. What's going on after a few hours is different.
Maybe your hunger is linked to hormone levels and brain chemicals. Something beyond what you can make sense of. I notice this happens to me sometimes. I've recently noticed that during menstruation i am more hungry for comfort foods. When i am depressed, i am more hungry. Unless I"m REALLy depressed then i am not hungry at all.