I am a big fan of Nancy Clark's approach, and have two of her books.

The Carmichael Training Systems Coaches have a similar guideline about eating before exercise. Ideally, they suggest you have a big meal about 3-4 hours before a workout. Clearly, that isn't always possible, and the closer you are to the start, the smaller the meal should be, say a bagel or a banana if it is just half an hour before. They recommend mainly carbs shortly before/during the ride. Also, the half hour or so after you finish the workout is a good time to replenish your energy- the muscles continue to gather energy as if you were still working.

You can store enough glycogen for an hour or two of exercise, but after that you need to eat 100-200 calories an hour to refuel. Carmichael coaches suggested eating about an hour into the effort.

Personally, I'm usually good with just water for up to 15-20 miles (a little more than an hour) unless I haven't eaten for a while. I've followed that guideline of eating 100-200 cal/hour on long rides/ events and have never bonked.