I found it hard to start this book because it meant I'd have to do something about my pot belly which is exactly the reason why I needed to read it. Not wanting to give up my beer or actually do anything approaching physical work I finally got to opening it up and was surprised that I enjoyed it.
First thing, it's for geeks as the title says. The blurb says any kind of geek (someone obsessive about a subject) but it tends towards software speak which might go over a lot of non computer geeks heads. Having said that, there is a lot of good advice that is understandable to all. Widgets and gadgets used to be the domain of proper geeks, now everyone uses them and there is a good chapter on these and how they can aid your progress tracking.
The content ranges from evolutionary fitness (is sitting in front of a screen really what we are evolved for) to a comprehensive discussion on food science (what are carbohydrates, High Fructose Corn Syrup etc) with plenty of other content (interviews, food choices, gadget guides, exercises).
It can be very heavy going if you read it cover to cover but used as a reference manual or to help you plan your diet, activity or sloth a bit at a time then it works well.
In summary, if you want to track, report and manage your exercise regime in detail then this book has plenty of advice on what to look for and possibly what to buy. It's not a page turner, but then is any exercise book? Although it says it is for nerds of all sorts, you'll need to skip the computer bits if you are not a software developer.
So, have I lost my pot belly? Nope, I'm already following a lot of the advice anyway and for me personally, it just boils down to eat less and exercise more (more than walking the dog anyway).