Carbohydrates have gotten a "bad rap" in the last several years. For every article or non-standard diet that demonizes carbohydrates, you'll find an equal number that doesn't. Notice the discrepancy with the first answer posted here.
Except under conditions of starvation, it was thought that the brain
always had an ample supply of glucose. "While this is the case in
terms of consciousness, the new findings suggest that glucose is not
always present in ample amounts to optimally support learning and
memory functions," said Gold, who is director of the Medical Scholars
Program in the University of Illinois College of Medicine.
Any Registered Dietician will tell you that removing all carbohydrates from your diet is not a good thing because carbs are an essential nutrient. Not only do they provide energy, but, they assist in brain functioning. And, while there's no agreement on the long term efficacy of zero carbohydrate diets, the potential implications are widely known.
The best that you can do for yourself is to become knowledgeable on how certain foods affect you because, regardless of popular opinion, there's no such thing as a universal diet that meets the needs of all people.