Recently, I've been hearing from many patients who have read Dr. Perlmutter's new book, Grain Brain
, and are now concerned about their carb intake. In his book, Dr. Perlmutter suggests that dietary carbohydrates cause high blood sugar, inflammation, and other effects that lead to a "toxic brain," which can then develop into neurological conditions such as Alzheimer's, Parkinson's, depression, and others. Based on this line of causality, he recommends that everyone consume a very low carb diet (<60g per day) in order to prevent neurological disease.
First of all, I'd like to point out that very low carb (VLC) and ketogenic diets can be effective therapeutic tools for treating many neurological disorders. I touched on this briefly a while back in my podcast with Emily Deans
, and initial studies on low-carb diets and mental health have shown promise. (1
Because Dr. Perlmutter is a neurologist, it makes sense that he would be a proponent of low-carb diets for his patients based on these therapeutic effects.
However, recommending a low-carb diet as an intervention for sick people is very different from promoting it as a preventative measure for the entire population, which is what Dr. Perlmutter does in Grain Brain
. His approach would be somewhat akin to recommending that everyone go on the Autoimmune Protocol to prevent autoimmune disease, which would be unnecessarily restrictive and unhelpful.
It's important to realize that just because a low-carb diet can help treat neurological disorders, doesn't mean the carbs caused the disorder in the first place. While I don't argue with the idea that refined and processed carbs like flour and sugar
contribute to modern disease, there's no evidence to suggest that unrefined, whole-food carbohydrates do. In fact, there are three compelling reasons why this is not the case.