Equus, I think what you say makes a lot of sense. In my case, I believe the soreness and fatigue are the result mainly of too many, or too hard, efforts well up into my red zone for HR. But, I have been experimenting with really counting my grams of carb intake, especially on the bike. Oddly enough, I have been making sure I don't take in too many per hour. It was causing me intestinal distress. Now, I'm eating more often on the bike, but smaller amounts, and it seems to help regulate my energy and digestion.

But, I do support your point. Last year, during the winter, I was doing some dieting and training at the same time. I finally got quite run down, and realized that for me, hard training and too severely restricted calorie intake just don't mix. Duh. But, for awhile, it was fun to have some weight drop off!