Sodium in tuna can be a problem, depending on your sensitivity to it. I eat canned tuna while dieting, but it makes up a fairly low percentage of my entire meat protein intake. Chicken is #1, lean red meat #2. But I think tuna a few times a week is ok. It's still a great, lean, cheap protein source. And, if it's any help, water retention from high sodium levels is a very temporary condition. That water goes away within a matter of a day or two once sodium levels are significantly lowered.