i agree that you need to be eating more before or even taking a snack break during. eating food isn't like depositing cash into your bank account where it goes in and immediately becomes available for use. because of digestion it takes some time. so if you're inhaling everything after, you need to eat more before (or during) so that you aren't trying to eat everything in sight.
what you eat depends on you and your stomach and how it sits during your workout. my go to is a half bagel and cheese. occasionally i have a spoonful or two of yogurt (quantities of yogurt don't sit so well with me) or peanut butter or a half cup of fruit like watermelon or a hard boiled egg. if i know i am going a longer distance ill have gu or a block or something during. that's for morning workouts. if i know i am working out later in the day, i just try and eat a little larger portion of my meal at least an hour before i start. what rarely matters later in the day.
and that is what you have to figure out. what can you eat before and during that doesn't impact your workout and doesn't leave you ravenous after?
-google first. ask questions later.