So how does your reward system work?
There’s apathwayin your brain, a neurochemical pathway, sometimes called the hedonic pathway, a pathway to pleasure, if you like. It is a communication channel from a part of your brain called the ventral tagmental area or VTA to your nucleus accumbens -we’ll call this Reward Central.
When you eat something tasty, this alerts your VTA and triggers it to send a signal to Reward Central to release dopamine. The result is that you experience a feeling of pleasure.
So what is dopamine? Dopamine is a neurotransmitter. A neurotransmitter is something that signals between one part of your brain and another. In the case of dopamine, between your VTA and Reward Central. When dopamine is released it produces a feeling of pleasure.
This pleasurable feeling is a reward. A reward for eating, for supplying your body with food that it can convert into energy. A reward for doing the right thing to ensure your survival.
Once you have had enough to eat, the feeling of pleasure subsides. Your VTA receives a signal to stop releasing dopamine and you stop eating. Where does this signal come from? It comes from leptin. Remember leptin, the messenger from your fat cells who says you have enough energy and you do not need any more food? Leptin switches off reward. The motivation to eat disappears.
Insulin also has a role to play. The rise in insulin, which happens when you eat, also helps to blunt the feeling of reward. You no longer feel the need to continue eating. This is an important safety mechanism because it allows you to enjoy a slice of chocolate cake and really enjoy it, but stops you from eating the whole cake. You can see that both leptin and insulin are important regulators of your reward system.