Long Distance Runners?

Hi everyone! Im 45M, 5’10” and 245lbs. I’m looking for fueling and nutrition training tips as someone who had gastric sleeve surgery. I’m currently training for the NYC Marathon (this will be my first marathon). I have completed a handful of half marathons already.

I’m interested to know about fueling during the long runs. When i ran the half’s, I basically had huma gels every 3 miles or so and whatever fluids at the hydration station. But admittedly I am nervous about those longer distances.

Any tips are greatly appreciated.