A new book about grains is drawing criticism from some experts.

Dr. David Perlmutter’s “Grain Brain” claims that grains and sugar could have a toxic effect on your brain, leading to depression, ADHD and even Alzheimer’s.

Perlmutter joined the hosts of Fox and Friends this morning to respond to his critics.

Julie Miller, of St. Catherine University, said, “He has many themes in there, it’s hard to know what to talk about. It’s like a field that has good plants, some you are not so sure of and weeds.”

Perlmutter responded to that critique by remarking that Miller is a paid spokesperson for the grain industry.

 “Several critics …have pointed out that readers may interpret his book as a green light to load up on meat and dairy instead, a choice that has its own well-documented cardiovascular heart risks,” Gary Drevich, of Forbes, wrote about “Grain Brain.”

But Perlmutter says his book is not a call to eat lots of meat and dairy. “It really relegates meat and dairy products to being sort of like the garnish on the side of the plate, pretty much a much more vegetarian diet, and keep in mind the meat that you want to eat should be grass-fed, much lower in terms of it causing inflammation in the body, which is really a cornerstone of Alzheimer’s,” Perlmutter said.

The book has been on the New York Times bestseller list for 16 weeks.

Watch Perlmutter’s full interview above.