Activation of certain neurons in your hypothalamus can either trigger hunger or reduce hunger, which in turn leads to weight gain or weight loss. The neurons that reduce hunger are called POMC neurons. When these neurons are activated, they release a neurotransmitter that reduces the desire to eat. The hypothalamus also has a negative feedback loop that stops this POMC activity and signals that it’s time to start eating again.

The mesolimbic reward system is involved with feelings of pleasure during rewarding experiences such as eating. When you eat – or sometimes even just think about foods rich in sugar, salt and fat – it can stimulate the release of neurotransmitters such as dopamine. Over time your brain seeks to repeat those rewarding eating experiences, which is how cravings begin. At times, those cravings can seem uncontrollable, even when you’re not hungry.