Why We Get Fat: And What to Do About It
By Gary Taubes (2011)

This is a must-read for anyone who is overweight.

Diet 101: The Truth About Low Carb Diets
By Jenny Ruhl (2012)

Easy to understand, well-explained, Jenny tells it as it is.

The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable
By Jeff Volek and Stephen Phinney (2011)

A good primer on low carb diets

The Art and Science of Low Carbohydrate Performance
By Jeff Volek and Stephen Phinney (2012)

Great information for athletes who want to use ketogenic diets to improve their endurance and performance.

Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health
By Gary Taubes (2008)

This is the much heavier, in-depth version of my first recommended book ('Why We Get Fat and What to Do About It').