This book is simply outstanding, highly recommended if you have diabetes, prediabetes, or just want to know more about how to keep this from happening to you.
The core message of the book is (1) that blood sugars over 140 are damaging, and that you should keep your blood sugar below this level all the time, and (2) that keeping your blood sugar below 140 is something that everyone can do.
The problem with blood sugars over 140 is that they cause diabetic complications: increased heart attack risk, nerve problems, eyesight loss, kidney problems, blood vessel and circulation problems that can lead to amputations, etc. High blood sugars also accelerate damage to your pancreas, so that you get ongoing higher and higher blood sugars, a vicious circle. Not fun stuff.
