Marathon Diet

I keep reading that the best diet for marathon training is based on carbohydrates with a low glycemic index. The theory is that this diet is optimal for storing glycogen in muscle tissue and therefore good for distance running (glycogen is the form of sugar your muscles like to burn when you're exercising for a long time and what finally gets depleted when you hit "the wall" at mile 20, so obviously, the more glycogen, the better). The optimal diet seems to be about 60-65% carbs, 15-20% protein, and 15-20% fat. I'm all for glycogen storage, but this diet is HARD, even for someone who will eat almost anything. For one thing, it has forced me back to near-vegetarianism because it's the easiest way to cut out protein and fat and load up on whole grains and veggies. Don't get me wrong--that's not a problem; I was a great vegetarian for many years. But I know this diet is going to lead to an increase in my husband's fast food intake to satisfy his meat and fat cravings, and I worry about his coronary arteries. Also, it would be dishonest to deny my own cravings: I have had dreams about crab and lobster in clarified butter recently, which clearly do not jive with my current regimen. The other thing is that I've always assumed that serious athletes have dead tastebuds because the food they eat looks like it would taste absolutely awful. Why else would energy bars exist? As someone who loves cooking and food, it's a struggle. The facts are that fat carries flavor and bacon makes everything taste better (facts that I denied while I was a vegetarian). It's going to take some experimentation. If I have any culinary breakthroughs, I'll be sure to let you know.