To tell the story of what sugar does to your brain, you have to start with the thought that triggers your need for a hit of sweetness.
It often happens in the afternoon when your brain, which runs on sugar, starts to get hungry.
To satiate the craving your brain activates a string of neurons, often referred to as the reward pathway, which pump the chemical dopamine into your brain.
All of a sudden you need a chocolate bar or that sweet pastry you saw at lunchtime.
If you act on that craving, the reward pathway then switches mode, pumping chemicals such as beta-endorphins into your brain, generating feelings of pleasure.