High protein Low fat?

Lots of chicken and vegetable based meals - grilled chicken and steamed veg, stir-frys with some nice spices and crunchy veggies, casseroles and stews with light sauces. Maybe some steak, depending on the cut, and again pretty versatile to work with. You could use eggs as a protein source as well, and put some hardboiled eggs into a salad instead of meat.

Don't forget about fish too; you can use canned tuna and get creative.

Chicken breast. Any other cut of chicken (dark meat) has twice the fat as breast does, and a tiny bit less protein.

Octopus and Squid, gram for gram, has less fat and more protein than chicken breast, but cholesterol in squid is twice as high (same amount as eggs if I recall correctly). Cholesterol for octopus is pretty normal I'd say, I little higher than chicken, but not by a lot. As to whether the cholesterol we consume makes any difference to that which we produce is an ongoing debate. So whether it's worth it or not is up to you entirely (personally I think it is)

Cod has less fat than salmon and tuna but also a little less protein, but the up side to this is that you can have unlimited amounts of it, whereas with salmon and tuna (oily fish) you're only meant to be having 2 - 4 portions a week depending on your gender.

Bell peppers, onions, cucumber, tomatoes, spring onions, are all really low fat and low cal. As is skimmed milk.