At 10 weeks onwards, I've been eating much the same as I am today (just over 6 months out). White and oily Fish, chicken, small amounts of beef, lambs liver, venison - probably most of what I was eating pre-op, which I've always felt I was somewhat fortunate compared to what some other sleevers have written here.
The only difference is at 10/13 weeks I was not eating any stodgy carbs at all (bread/potatoes/pasta/rice) and now I have them, every now and then, but in v.small amounts as I've been sticking to the "rule" of protean, then salad/veg then carbs when eating.
Portion size, I'd say for a main meal i'm use a side plate of food (less than 20cm in diameter) now and at 18 weeks. If eating out - at 18 weeks I was eating around a 3rd on what was on the plate - now around half.