> is it possible to be in a caloric deficit and still gain weight if this is true? No, that would defy the laws of thermodynamics. However, it is possible to c

> is it possible to be in a caloric deficit and still gain weight if this is true? No, that would defy the laws of thermodynamics. However, it is possible to consume more calories than you burn and lose weight, because there are complexities around how your body decides to store fat, signals to burn fat, etc. Even if it was simply a thermodynamics problem (which I don't think it is), there are also issues with appetite. Sure, you can count calories for the rest of your life, but doing that is not only difficult to measure correctly, but very difficult to maintain if you still feel hungry all the time. I think one of the reasons a ketogenic diet works for a lot of people is that after a period of adaptation, you stop getting hungry every 4 hours.