Overall, I have enjoyed this book. The historical parts of the obesity research are solid and well told. The references are often fascinating, and I have found a few scientific papers I found very interesting.
A relatively minor quibble is that the author seems never to have encountered LCHF, and seems to think that fat is one of the chief problems with the modern diet. Just looking at what people ate 100-200 years ago should dispel that impression. If not, then looking at just about any review of low-carbohydrate diets for weight loss will.
There is a problem with the fat, but it's not the macronutrient per se, but rather what we have replaced the natural animal fats with - industrial seed oils.