Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Rather technical but it's working great for me!

I was on a low fat/high carb diet for nearly a month and found my willpower waning. A friend at the office told me about this book. So I tried it. I've lost 15 pounds in 12 days! And still droping a pound a day...Wow! This book is rather long on the chemistry of why this works. I really didn't care so much about that, I am just glad it works.