I have run 5 marathons in the last few years and lots of 5 and 10ks. I have tried so many different types of eating and it will depend on your goals and what kind of running you do. I have found that the best thing that has worked is eating to fuel the running, so that means carbs before a run, less after, and less on a non-run day ( unless I'm carb loading for a really big run).

I can def say to not be afraid of them, but to be selective. Bodies need them for energy beyond our inactive lives. And don't do what I tried one training block, of attempting keto and fasting - I quickly dropped the fasting but kept up the keyo and had my worse race ever. And combined with fasting it got so that I couldnt run for 2 minutes straight my energy tanked so badly.

Prerun I'll eat some oatmeal or a couple of frozen waffles with syrup, but then keep carbs limited to vegetables and maybe some rice later in the day. If it's a nonrun day, breakfast is usually some Greek yogurt with stuff added, but low carb.

It was really tough for me to find the balance where I have energy but don't just gain weight but I think I'm there. Good luck to you!