calorie in/out is true, BUT we have no way to measure what we put in and out. That's the problem with most peoples simple assumptions "you have eaten so and so

calorie in/out is true, BUT we have no way to measure what we put in and out. That's the problem with most peoples simple assumptions "you have eaten so and so many calorie, therefore .." - it is completely unimportant what you eat. It is important what is usable by your body. And there the "calorie in != calorie out?" research starts ..