I track my daily food, though I don't pay it much attention beyond adding it to MyFitnessPal. My diet is pretty static, with mostly the same food each week, so I'm sure I'm hitting my goals for nutrition.
My half marathon routine is to get up three hours before race time and eat a meal bar and drink a bottle of Gatorade. I wash it down with a cup of coffee to help it all pass before the run. This gets something like 700 calories, electrolytes, and fluid in me ahead of the run. My nutrition during the run is to eat an energy gel every three to four miles. It isn't that I need a gel after three miles, it's that around mile nine I needed one six miles ago. I bonked on a 20K a year ago around mile 9. I've seen writeups where runners scoff at any nutrition for runs under twenty miles. There's an Ed Viesturs quote that goes something like "all I know is this is how I like to do it." I think that applies here, too.
The advice I most agree with is to experiment. See what works for you during training runs, and do that on race day.