I ran a half marathon today in 2:08. This is significantly faster than my best time so far and at the same pace that I could barely do 10 miles in while on a low carb diet. Besides vastly expanded cardiovascular capacity, I’ve noticed a few other changes after dropping low carb:

*A slight bump in mood. Sugars tend to make me happy.
*A return of the mid-afternoon nap-urge.
*Small increase in ability to lift weights.

Assuming the two were equal difficulty, I would stick to low carb. The level amount of energy throughout the day is wonderful as is the fact that low carb almost forces me to do low calorie. I will re-try on Monday.