500 calories makes a big difference. It's the difference between maintaining and gaining for some people. Focus more on that first. That being said...
Lower your carbs and protein. With only 75g carbs a day you may as well look at a keto diet. Up the fiber, drop the protein to ~190-200 and put your fats at 190g.
If you keep your protein that high (400g, wtf? Are you using a hormonal? Then that's too much.) your body is just going to use it like it uses carbs, and it can start to add fat. Again, since your body doesn't need that protein, it will store it for later, as fat.
Focus more on whole foods that are moderate in protein and high in fat. Some of the best ones that I utilize are walnuts, almonds, and sunflower seeds. Since we're dealing with fats and protein 'lean meat' is not necessary, save your money. Using olive oil in cooking, or just a tablespoon will provide ~15g fat (135 calories)
Increase your fat and lower your protein, you will be surprised.