I am have difficulty in gauging food/calorie / protein intake for a 52km trail run I am doing in two weeks. The road ultras I have completed I did not find keeping fuelled difficult.
But with training in more hilly conditions I have found a dip in energy after 4 hours. I would try to be as full as possible prior to my long runs. Any one any advice on high energy foods I could try as I am using gels and they are not working too well.