Dr. Perlmutter scores again with a great book, this time about the profound impact of gut flora on our health. As patients and people we have been taught that having a propensity to get fat, dementia or cancer is “genetic” and we are mostly helpless to change that. Yet, the research shows that our second genome, that of our gut population, could be a much more relevant and powerful factor than our own human genome.David Perlmutter enjoys a privileged position of being a physician, therefore people listen to him. This information is well cited, based on research and brings it to the masses with his approachable, conversational style as well as his unabashed enthusiasm for the potential of treatments and cures for his patients. He starts with the research that makes foundational concepts: sterile mice implanted with gut flora from slender mice stay lean, mice implanted with obese mice get fat when given the same diet and environment. Then he expands to the more abstract information like the detrimental effects of antibiotics and the study that showed women who have undergone the most days on antibiotics have twice the rate of breast cancer. He shows how poor gut health causes high blood sugar, inflammation, decreased resilience to stress, sleep and cognitive difficulties and more.The angle that is original in this book is the relationship of gut dysbiosis and brain diseases and practical application of gut healing. People suffering from major depression, Alzheimer’s and autism have high rates of gut dysbiosis. In his practice, when he corrects the gut imbalance in people with these and other neurological diseases, symptoms often decrease or sometimes disappear. These are diseases with no accepted “cure”. He peppered his book with anecdotal reports of his patients having mind blowing transformations like these after taking very intentional steps such as diet modification, eating fermented foods and even probiotic enemas. Hopefully there will be some real research in this area someday. His epilogue seems optimistic that sufficient research will happen. I doubt this field is getting the true attention it deserves. He shows no criticism towards the “system” at the fact that fecal transplants are only approved for C.diff patients yet people with IBS and other diseases get radically great results from them. He matter of factly tells us sends his patients that need a fecal transplant overseas. Well good for those who have the luxury of seeing the celebrity doctor then jet set to Europe to get their treatment. What about the rest of people suffering?I think this book is great in the way it shows the whole picture of the gut flora from the negative effects of cesarean birth, rounds of antibiotics, chemical exposure and a western diet. He clearly outlines a path to reversing a damaged gut. The one criticism I have is that he recommends a high fiber diet heavy with fermented foods and includes a week long diet plan. He also give instruction on how to ferment to make this lifestyle affordable and accessible to all. However, adding 3 servings a day of billions of bacteria a day can cause digestive distress to most people accustomed to the standard American diet. I would recommend a gradual introduction instead.Overall, it’s a great book. It’s well cited, clearly organized. He quotes top scientists and researchers that all share his enthusiasm for this frontier of healing and understanding the human body. It’s not dumbed down yet it’s understandable enough for the common reader. This book will be groundbreaking in increasing awareness of this emerging field that affects us all.