When it comes to winning the war on body fat, it’s very much about the physics of energy. The way in which your body either shreds or stores fat is all about what happens with your calorie intake and energy expenditure. Let’s say you treat yourself to a few days of eating whatever and as much as you want. You’ve fed to excess and your body now has a surplus of food energy (calories). As far as your body’s concerned, this is great. It has no idea where the next meal is coming from and because it thinks that you’re still a hunter-gatherer on the Serengeti, hunting for your meals with spears and axes, it’ll do all it can to save that those calories for later. It needs to make a decision – get rid of this excess energy and risk starving, or store it somewhere and give your self a ‘calorie cushion’ in case you struggle to find your next meal.