Calories in < calories out will, physiologically, undisputably, result in 'WEIGHT' loss, not neccassarily fat loss. To use an extreme example, if you where, hypothetically, someone who required 2500 calories for exact maintainance, 0 weight change, if you where to do intense heavy lifting when you woke up, fasted, then just before bed, eat 2400 calories, well 2400<2500, you think you are going to loose fat? fasted cardio is a good way of ensuring that your 'weight' loss is coming in the form of fat loss, because when insulin level are lowest, your body is better suited to use fat as energy. What people also have to realise is, it isnt a 24 hour hour nominal process, while you might use an average of say 3000 calories a 'day' you arent using them at a constant rate, if you are sedentary for a 12 hour period, and consume most of your daily calories, you are eating more calories per hour than you are using. and your body can only store so much before it puts it away as fat. its a continuous process.