I think it’s harder to find fish in water, and it’s more expensive. Costco, for instance, has tuna and salmon in water…all the rest is in oil.
And Costco is waaaaay cheaper than most other places. I love some smoked fish, like this:
But at Costco, you get a lot more fish for a lot less.
I’ll see if I can report back the exact costs.
As for magnesium, I’m not sure about that. At one time, I made sure to eat canned fish several times a week. Then once a week or so. Now, I rarely eat canned fish. I know, but my Omega 3, blah blah blah…
I’m not convinced that Omega 3 is that necessary if overall PUFA is low.
Either eating fish or not eating it hasn’t seemed to affect getting cramps or not.
It were up to me, I’d rather eat real fish instead of canned (though I do like some of the smoked canned varieties).