Here’s what happens when you interfere with your hypothalamus – when medical advice collides with psychology. Let’s say you decide to cut back on calories. You eat less for a day. The result? It’s like picking up a stick and poking a tiger. Your hunger mood rises and for the next five days you’re eating bigger meals and more snacks, perhaps only vaguely realising it. People tend to judge how much they’ve eaten partly by how full they feel afterward. But since that feeling of fullness is partly psychological, if your hunger mood is up, you might eat more than usual, feel less full than usual, and so mistakenly think that you’ve cut back. You might feel like you’re making progress. After all, you’re constantly vigilant. Sure, now and then you slip up, but you get yourself right back on track again. You feel good about yourself until you get on a scale and notice that your weight isn’t responding. It might go down one day and then blip up the next two days. Dancing under the surface of consciousness, your hunger mood is warping your perceptions and choices.