Serenity - eating tuna every day probably is not healthy, in terms of mercury consumption. Here is a handy calculator to figure out what is a safe consumption, based on weight: http://www.ewg.org/research/tuna-calculator
This is also a good chart, to expand the conversation to more fish types than just tuna: http://www.bodyrecomposition.com/nut...d-mercury.html
Wish you the best, Ian. If it works for you, good. I know some people fine with mono-type eating over the long-run. I can't help but think how it's possible to have too much of a good thing, and that diversifying one's diet is protective (against too much of one thing, too little of another). I know you've done a lot of research though, and I'm glad you stay away from higher mercury choices!