Man full fat - or even 2% - is like crack to me. Fat Free cottage cheese isn't even food, though. Anyways, if you're looking for a hit of protein with no other macros have you thought of getting some protein isolate? True Nutrition sells the best IMO. They have a few different types that go through different microfiltration processes but in the past I just got this one. Fair warning on this stuff, if you add it to something else or add flavor to it it tastes fine but by itself it tastes like ass. Also, in dry form it's no problem but the second you add water to this stuff it starts degrading, so if you let it sit around after adding water for like 5 minutes it smells like a fart; I've made the mistake of not washing my shaker bottle out right away after using this, and letting it sit all day, and it reeks. What about greek yogurt? Turkey? Shrimp (I keep a bunch in my freezer for exactly this reason)? There's tons of options besides canned tuna (YUCK).