Marathoners/Marathoners-in-training

So after running three half marathons (and one more in July), I’ve decided to go for the big one - a full marathon. The only problem I have is that I cannot eat or drink during a run. I can make it through a half marathon (although I do get pretty hungry around mile 11) but I know I won’t make it all the way through a full marathon without eating or drinking. Does anyone have any advice about the best way to start integrating eating into my runs? Any suggestions for gels/goo that aren’t completely nauseating? At what point in the race do you start to eat?

Any advice would be greatly appreciated. Thanks!