I guess the carb thing your dietician said still makes sense for me if I take into account calories over the whole day and not per meal. Surrounding any 2 hour workout aerobic intensity or over, I'm taking in carbs like crazy. 2 gus, 2 bottles accelerade, a PBJ or banana before... That gets my percentage of carbs per day into the 40-50% range, where without those, it's down near 30%. Sometimes even closer to 20-25%. I don't feel good when I get 50% of calories from carbs in a meal. I try to limit my carb intake per meal to under 25g unless it's right before a massive ride.