To clarify, the only harmful fats are trans fats. We need unsaturated fats *and* saturated fats. It's just harder to get those unsaturated fats.

So... ideas: make sure your mayo is canola oil (or other healthy oil) based, and/or mix in some healthy oil with it. You can even make your own mayo. Now, I happen to dislike mayo: I mix tuna with cream cheese! It's great! I like to drizzle a little olive oil on my cooked veggies, then sprinkle on some feta or parmesan cheese. I also "spike" my store bought salad dressing with olive oil once I've used a few tablespoons of it. Many people just suppliment with fish or flax seed oil.