I love tinned tuna! But I have recently gone to eating half a can rather than a whole can, as I have gained a bit of weight. Mind you, it's probably not the tuna, it's the amount of home made mayonnaise I have with it ;)
Raw, try Sainsbury's own brand tuna in olive oil, it's my favourite, to my surprise better than Waitrose's, £4.50 for 4 cans. Sainsbury's also do canned sardines in olive oil, and sardines are, as I suspect you know, fine to eat more regularly as they are lower in the food chain.
Stuffez, if you are fine with dairy, then I see no problem in you having Greek yoghurt (get the organic, though), as it's fermented and high(ish) fat. I do recommend, as I have earlier in this thread, that you make your own coconut kefir, it's lovely and really good for you. I culture it untill it starts splitting, then I suck out the clear liquid from the bottom with a turkey baster (to get a firm texture) and then I strain the remaining coconut kefir through a sieve to catch the kefir grains. I usually just drink the clear liquid after chilling it.
I have had quite a food wise naughty Saturday, I have had gluten free birthday cake as it was my son's 6th birthday and I have also had Paleo pizza (grated potato base) and wine. But it's so much better than what a food wise naughty day used to be! I am going to go a bit cleaner next wee, though, as I have to major spots on my chin and cheek! Doesn't help that my period just started, only makes the sots and cravings worse.