Nice post... Very informative. I'd start eating some nuts. Easy way to boost your caloric intake without having to eat crazy amounts. They're the "good" fat, too.
Re: Tuna
You have to watch how much tuna you eat out of a can... It's not so good for you. A friend of mine got mercury poisoning. Obviously it's okay to eat, but I just wouldn't eat it every day. Same with canned salmon.