Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Where is the evidence?

When I first saw this book, it really got my attention. The concept that we should eat according to our blood type because this is what our ancestors did is both new to me and intriguing. However, being a man of science and facts, I decided to do some research before subjecting myself to these dietary recommendations. Sad to say, Dr. D'Adamo's books and website are full of stories about how people lost weight or became healthier after undergoing his dietary recommendations. I did not find any shred of scientific evidence that the system as a whole works. Where is the double-blind randomized controlled trial that proves this system works? Where are the follow up studies? Shouldn't anything like this be published in a peer-reviewed journal? Stories and testimonies about how effective this diet is IS NOT science.