Food Addiction involves the same areas of the brain as drug addiction. The same neurotransmitters are involved, and many of the symptoms are identical. Processed junk foods have a powerful effect on the reward centers of the brain. These effects are caused by brain neurotransmitters like dopamine.
People with Food Addiction get their “fix” by eating a particular food until their brain has received all of the dopamine it was missing. The more often this cycle of craving and rewarding is repeated, the stronger it becomes and the greater the quantity of food that’s needed each time.
When ingested, sugar, flour, grains (and any other addictive foods) light up the brain’s “reward circuit” by flooding it with the chemical messenger dopamine. This reward system controls the body’s ability to feel pleasure and motivates a person to repeat behaviors needed to thrive, such as spending time with loved ones, physical intimacy or achieving a goal. Overstimulation of the dopamine reward circuit can cause an intensely pleasurable “high” that can lead people to eat these foods again and again.
When a person continues to compulsively eat sugar, flour, grains (and any other addictive foods), the brain adjusts to the excess dopamine by making less of it and/or reducing the ability of cells in the reward circuit to respond to it. This reduces the high that the person feels compared to the high felt when first eating these foods—an effect known as “tolerance” which causes one to then eat more of the food, trying to achieve the same dopamine high. It can also cause less pleasure to be accessed from other things previously enjoyed - like social activities.
Long-term compulsive eating also causes changes in other brain chemical systems and circuits as well.