I try to eat consciously and choose foods that will fuel my running. This means whole foods with minimal processing and additives. I believe in eating full fats (whole, raw milk!) and also pairing my carbohydrates with fats (bread and butter! veggies and butter!). I find Nina Planck’s book, Real Food: What to Eat and Why, very instructive.
Before working out, my current go-to snack is: homemade yogurt with granola and raisins; a hardboiled egg with salt; and a glass of water. I eat it one to two hours before leaving the house. Other than that, I bring a 24 ounce water bottle with me to the gym. (I leave my water at home if I’m running outside.)
There’s some controversy over whether runners should eat on the go. Here’s an interesting article on the subject.