Running is going to make you hungry. This is great because a) food is delicious and b) if you take a little care over the ingredients you use, you can get some powerful nutrients in your body which will add to the benefits you’re already getting from training.
Just like with any other aspect of your regime, the most important factor determining the effectiveness of your nutrition plan is whether you actually stick to it. If you don’t get that part right then none of the rest really matters. There is no point concocting the perfect blend of spirulina, raw biltong and ground flax seeds for your post-run snack, if realistically you’re going to find that way too difficult to stomach after you’ve got out of bed earlier than usual to do interval training first thing on your Wednesday morning.
The best running food will ideally be nutritious enough that it actively helps your body adapt to your training. It will be easy to prepare and store so that it doesn’t become an inconvenience. It will be cheap enough that you can eat plenty of it without it any negative financial impact. And finally, it will be so delicious that it actually increases your motivation for training.