I just joined this subreddit and i see people talking about gels and snacks… what are those? … i run 10/15ks sometimes and i cant carry water because i cant run while holding something and i always feel like i am dying by the 9th or 10th kilometer. Am i supposed to be “refueling” (that is also a word i picked up rn from this sub)?

Can anyone point me to some resources for this. Seems like I’ve been doing it all wrong.