This can happen to some when they switch from a diet high or relatively high in carbs to one in which carbs are restricted - it is temporary. I can attest to that! I eat very few carbs and can still run my own business (writing) and perform improv shows with no problems. No cognitive fatigue here, nor has there been for the past 2.5 years. Prior to that - wowza, whole other story!
________________________________
From: Juergen Botz <[log in to unmask]>
To: [log in to unmask]
Sent: Sunday, December 14, 2008 11:25:53 AM
Subject: Article: Low-carb diets affect cognition skills
Not directly a paleo issue, but interesting:
http://www.scienceblog.com/cms/low-carb-diets-affect-cognition-skills-17983.html
For my own part, I start my day eating a lot of fruits, so no
carb-deficit early in the day. But having read this, I'm going
to pay more attention to my attention-span in the afternoons
and experiment with snacking on more fruits to combat any
cognitive fatigue later in the day.
:j