If you've tried dieting or portion control primarily for weight loss- you know those days or weeks when you eat less are brutal. Well, your lack of will power or total hangry feelings may have to thank one specific group of brain neurons. A study conducted found that when mice lost weight, a group of neurons—called "AGRP neurons"—switched on and seemed to foster "unpleasant or negative emotions" in their brains. It's already been shown that these hangry neurons exist in human brains, also. It may seem obvious that going hungry would lead to "bad" feelings. However this study is one of the first to explain where these bad feelings actually come from. AGRP neurons live in the part of your brain that helps regulate everything from hunger to sleep to your emotions. (Hence why we get a little cray) So why is this relevant? Well, the study also concluded that switching off these AGRP neurons in mice gave them the ability to influence the types of foods the mice preferred and even the places they liked to hang out. The same study is currently looking in to creating a drug that silences these hangry neurons, as it could be a great weight-loss aid. However, at this point, the study just provides a bit more awareness of what people are up again when they try to lose weight.