David Perlmutter is an American neurologist and author known for his work in the field of brain health and nutrition. He has written several best-selling books, including Grain Brain, which discusses the impact of diet on neurological health. Perlmutter advocates for a low-carbohydrate, high-fat diet to improve cognitive function and reduce the risk of neurodegenerative diseases. In addition to his writing, Perlmutter is a frequent speaker and has appeared on various media platforms to share his insights on the connection between nutrition and brain health. He emphasizes the importance of lifestyle choices in maintaining cognitive vitality as people age.