“The brain’s pleasure center, called the nucleus accumbens, is essential for our survival as a species. … Turn off pleasure, and you turn off the will to live. But long-term stimulation of the pleasure center drives the process of addiction.
When you consume … sugar, your nucleus accumbens receives a dopamine signal, from which you experience pleasure. And so you consume more. The problem is with prolonged exposure, the signal … gets weaker. So you have to consume more to get the same effect — tolerance. And if you pull back on the substance, you go into withdrawal. Tolerance and withdrawal constitute addiction. And make no mistake, sugar is addictive.”
“Every time you follow the same path, a specific pattern is activated and becomes more defined … and it becomes easier to activate the circuit the next time. … Pretty soon, the bad habit neuronal pathway becomes the unconscious default, and your brain, wanting to be efficient, just takes the easiest, most familiar route. This is particularly true in the case of depression.
In a depressed brain, there’s less dopamine activity happening in the nucleus accumbens, which means that things that used to be enjoyable are not as pleasurable, and the only things that motivate it have to have a big dopamine payoff, which are the baddest of the bad habits, such as junk food, drugs, alcohol [and] gambling.”SUGAR AND THE BRAIN