Eating for 3hr excercise

I am not sure what a derby is, but I suggest poking your head into some marathon websites or into the group here and see how they stay refuelled for their runs. Just a suggestion.

Hi there, I run marathons so I'm pretty familiar with fueling up for long exercise periods. You want it to be something easy to digest and portable. Low fiber so you don't get an upset stomach. When you're exercising for long periods, your digestive system slows down so that it can use the energy elsewhere. High fiber snacks will just sit in your digestive track. Runners often use things like Luna/granola bars (if they don't have too much fiber) or "gels" that you can get at a sports store. Its a small pack of gel that is 1-2 tbsp and usually has about 100-120 calories. It often has electrolytes and some have caffeine. If you don't want to go that way, try something with simple sugars like a handful of jelly beans or gummy bears. Hope that helps!

Look up Skratch Labs Hydration Mix.

Cyclists use it for long distance/endurance events. Works amazing. Also google search "allen lim rice bar" you can make them yourself, rice bacon and eggs, they taste amazing.

Better than trying to use a clif bar or other stuff.

I go to 3 hour zumbathons a few times a year and what I do is eat a big meal before I go, like lasagna, or something with carbs. It takes me 30 min to get there so the food as time to settle. You can also bring a protein bar to eat mid-way through.