That's part of the issue. Eating slower has been suggested to help losing weight for that reason - it gives your satiety response time to kick in.<p>The issue with calories in minus calories out is not equivocating the word "in", though. It is that it doesn't provide a useful model of how weight gain works. "Calories in" and "Calories out" are not independent variables, they are managed by the body's various feedback systems. Changing one of them will almost always change the other. Going for a run will make you hungrier, and undereating will lower your energy level and probably make you hungrier as well.<p>Based on a lecture of his I've seen, I'm convinced that his major hypothesis is God's own truth - that "calories in - calories out" is not a useful model for controlling weight, and that the regulatory systems of the body are what you have to get at to have a real effect on body weight. I am sold on the idea that diet is one way to get at those systems effectively. I'm eager to read his book to find out more about the case he's making.