Our brain is designed with reward and punishment systems. When we do something that our biology believes is good, we are rewarded with chemicals to make us happy, to feel content, and feel at peace. It’s the body’s way of saying, “Yes, please. More of that. Whatever that feeling is, keep doing that.”

When we touch a hot stove or eat something poisonous, we feel pain for the same reason. Pain is how our body tells us to avoid whatever we did. We remember pain very clearly–even years later–so we won’t repeat our mistakes.

Reward says, “Go".” Punishment says, “Stop.”

A person with a dysregulated reward system will chase those rewards, even if they cause personal, physical, financial, and spiritual damage. Drugs, certain foods, and behaviors can trick the reward system because they trigger the reward system even though you didn’t necessarily do anything good. You don’t have to find joy by accomplishing a hard goal and feeling good about it. You can get that same feeling by simply taking a drug, playing cards, or eating 1,800 calories.

Anything can be addictive. You may have heard someone say that marijuana is safe because it isn’t addictive. Wrong. People absolutely can–and do–get addicted to it. People get addicted to gambling, TikTok, and sex. None of those things are “chemically addictive.” None of those are regulated by the FDA or DEA.

Your mesolimbic system is the portion of your brain that regulates your reward system. Its job is to reward you for “good” behavior to get you to repeat that behavior. It does this through dopamine releases. Dopamine is a neurotransmitter, a chemical used by neurons to spread a signal through the brain to make us feel happy and content. We get dopamine every day from ordinary things like a great sandwich or receiving a compliment.

Dopamine affects memory, helping to concretize moments at the same time as a dopamine release. When we are rewarded with a dopamine rush, we remember exactly what we did to get that feeling so we will remember to do the same thing again in the future.

Imagine the first time you saw a tasty food—let’s say it was a birthday cake. When you were a toddler and had never seen a birthday cake before, you might not have realized that it was food. Someone put it in front of you with a plastic fork or helped you eat it. Once you tasted birthday cake, your brain was awash with dopamine, and you committed birthday cake to memory as something that you will want to have again in the future. After that, when you see a birthday cake, you instantly want a slice.

What addiction-generating substances and behaviors do is create an intense but superficial experience. They cause a spike of dopamine that is unnaturally high–way outside of normal experience–which lasts for much longer than ordinary. Doing this once in a while is fine, physiologically speaking. Repeated use over time, however, has a devastating effect on the brain. As you continuously crank up the dopamine levels in your brain, the body believes it doesn’t need to produce dopamine anymore. The brain responds by pruning the number of dopamine receptors. It’s just like muscles. Use them or lose them.

The part of the brain used to make you happy literally withers away. Without dopamine receptors, those dopamine rushes from habits are less powerful. The addict needs higher and higher doses. Worse yet, ordinary experiences will no longer be able to generate the amount of dopamine that they used to. Things that used to make you happy don’t make you happy anymore. Over time, the only source of dopamine comes from the addiction. Let me be clear: normal life becomes physically impossible to enjoy because of the damage to your brain from tampering with the dopamine levels.

But it gets worse.

Dopamine D2 receptors also regulate the frontal cortex, the portion of your brain that regulates self-control, emotions, and behavior. The frontal cortex is very underdeveloped in children, which is why they act impulsively and recklessly. People with head injuries from car accidents frequently have this portion of their brain damaged irreparably from hitting their head on the steering wheel. People suffering from this type of injury will sometimes act like children. Their ability to control their instincts is damaged. Addicts may seen increasingly novel, dangerous, and depraved activity to get even a fraction of the dopamine they used to get from a hug.

It is a form of brain damage. Luckily, it isn’t permanent. The addict recalibrated their brain in a way that makes it impossible to function normally without constantly imbibing the source of the addiction, and it’s a big deal. It takes time to do this to your brain, and it will take time to undo it. There will be a long period of unpleasantness while healing, which is a subject that gets a whole chapter later in this book.

We can actually see the damage done by addiction using brain scans. The brain of the sober, healthy person compared to the brain of the cocaine addict is easily distinguishable. Someone without any training could spot the difference with no effort—they look that different. The reduced activity of the frontal cortex is unmistakable. Interestingly, the brain imaging of a cocaine addict and an obese person will look nearly identical. Physiologically, the addiction to cocaine and food addiction is very similar. Both damage your impulse control, incidentally making you act more recklessly, taking on too much risk, and weakening your ability to fight the addiction.

Birthday cake and cocaine are more alike than you might think. Cake is full of refined sugar, shortening, and salt. These three things are highly rewarding foods as far as your brain is concerned. They will cause an enormous spike in dopamine, exactly like a drug.

Birthday cake does not exist in nature. It doesn’t grow on trees. Humans have been around for 315,000 years. Chocolate cake with pure sugar frosting was invented only a few hundred years ago. Modern confections have insane levels of sugar that our ancestor’s brains almost never experienced.

If you’ve ever seen how kids behave around sugar, you can spot the similarities. Parents might catch their kids sneaking cookies when they aren’t allowed, but they never seem to catch the kids stealing carrots from the refrigerator. The child will break the rules and risk the disapproval of their parents for cookies but not for carrots.

As an adult, the stakes are much higher. Adults don’t typically steal cookies. Adults steal cars, purses, and identities. Adults don’t just break Mom and Dad’s rules, they break laws. Adults don’t get grounded, they go to prison.