Running with a calorie deficit

Training for a 10 km (6.2mi) run has proved to be a lot more challenging then training for a 5km (3.1mi) was. To get up to the 5k distance, I just followed the program and gradually increased my running times. I'm learning that it isn't quite as straight forward to run longer distances.

I am consistently running into the same problem. On at least half my longer runs, I've bonked (run out of energy and hit the wall). I've played around with my pre-run food intake a bit, but there is one major hold back: the fact that I am maintaining a calorie deficit in my day to day life.

I feel like I'm stuck between two worlds right now: the world of running/triathlons, and the world of weight loss. I'm finding that those two worlds don't mesh that well.

A calorie deficit = an energy deficit.

It's a fact. A calorie is a unit of energy. In order to lose weight, you have to expend more calories then you consume. This isn't a state that is conducive to endurance events. For endurance events, your body needs easily accessible calories to give you quick energy to keep going.

I've always maintained that activity is not the way to lose weight. It's essential for good health and weight maintenance, but not actual weight loss. I honestly believe it would be easier to lose weight by cutting my calories sufficiently, and sitting on my butt most of the day. Then an energy deficit wouldn't have as much effect since I wouldn't be trying to do much.

Now, that doesn't mean I'm giving up either. I do have a plan to stop bonking during my longer runs. It includes restructuring my food intake on the days of my long run so that I'm eating more before my run. I'm also allowing a slight increase in my calorie intake on the one day a week that I run for over an hour. Generally speaking, I don't eat more due to activity, but it's time to start making an exception on days where the calorie expenditure is becoming that significant.

I won't deny I'm a bit nervous about getting this figured out in time. I have one more long run of 13km (8mi) prior to my 10km race. It's a tricky balance figuring out what to eat, without having too much in my stomach when I start the run.

Does anyone have any recommendations of good running books that talk about nutrition? It's time I start educating myself a bit more rather then just going on instinct.