need help

akgary

im traing for a half marathon, i run 5 days a week with 5-6 miles a day and my long run is about 10- 11 miles once a week, i have gained weight while doing this the last month about 6 lbs but everyone tells me i look smaller, what are the best foods to eat, so i dont gain?? i want to to this in a healthy way but i surely dont want to gain weight either:) any infor would be great thanks