Yes, you should eat after an intense workout. I like oranges, almonds or protein bars after a long run, but everyone is different.
One thing I found helpful was to walk around the supermarket after a really tough workout and try to determine what I was craving. I let myself consider anything in the store but was honest about whether I really craved it or not. I found that I REALLY wanted a package of roast beef lunchmeat. To me, that meant my body needed protein and salt after the workout....which makes total sense to me. If you happen to crave a doughnut, that would mean to me that you needed some carbs and sugar (which you can get from fruit too
Anyway, it helps to listen to your body as to what you might be lacking in your diet as well as the numbers on fitday.