A lot of hay gets made about The Obesity Code wherein the author claims that "calories in calories out" doesn't work. Obviously he's trying to sell books but t

A lot of hay gets made about The Obesity Code wherein the author claims that "calories in calories out" doesn't work. Obviously he's trying to sell books but the nugget of truth is that if you operate at a significant caloric deficit your body goes into "starvation mode" for lack of a better term. The result is that eventually your base metabolic rate also decreases which means you need to cut calories even further. For people who are significantly obese to begin with this can be unsustainable, and the author of The Obesity Code talks at length about how glucose levels respond to diet and eating patterns and play a significant role in fat metabolism.