forget eel pie.
i present.. unagi.
And, if you want good food, have you ever ripped a crab open with your hands then feasted upon its insides? No? Heathen!
Along the lines of what most people said - Eat 4-6 times a day (4 SOLID MEALS MINIMUM), drink lots and lots of water (milk included!), and make sure you are getting sufficient carb/protein intake! For the additional meals (if eating more than 4 times a day), you could look into a protein powder, or mass gainer. There are some good mass gainers, and some really bad ones. To start acquiring good weight, you're going to need a little fat in your diet. I'm not sure what your goals are, whether it be more muscle mass, at the healthy level on your BMI, or some other semi-athletic weight.
If coffee and cigarettes are your breakfast (not saying it is), you got to make that change!
From old experienced legends of the barbell - complex Carbs are your friend.