Rada, N. M. Avena, and B. G. Hoebel, Daily Bingeing on Sugar Repeatedly Releases Dopamine in the Accumbens Shell, Neuroscience
That freshly baked batch of chocolate chip cookies cooling on the counter is calling your name, and you give in to its siren song. “I’ll just have one,” you tell yourself, until one turns into two, and three, and five, until your mouth is coated in stickiness tinged with regret. Even though you may have done some damage to your diet, you tell yourself that things really could be much worse. You could have a drug problem instead of a cookie problem, and those are completely different, right?
Wrong. Binge eating sugary foods can have the same effects on the brain and on behavior as drug abuse does, according to a 2005 Princeton University study by Rada, Avena, and Hoebel.
Dopamine is an important neurotransmitter involved in motivation and learning, especially when it comes to pleasurable behaviors. When we experience enjoyable things, dopamine is released into the nucleus accumbens, an area in the brain commonly referred to as a “pleasure center” because it is related to motivation, reward, and enjoyable activities.. This dopamine release is a normal part of our day-to-day life – it occurs when we eat our favorite food, for example, and when we have sex. However, drug addicts show some very specific behavioral and neurological symptoms related to this brain system: they become highly sensitive to dopamine, binge on drugs when they become available, show signs of dependence and withdrawal when their access to the drug is cut off, and have chemical imbalances in the parts of their brain related to motivation (drive to obtain the reward) and satiation (feeling satisfied when the reward is obtained).
Rada, Avena, and Hoebel experimented on rats in their lab. The rats were allowed to consume sugar for a limited amount of time every day, but were deprived the rest of the time – the perfect recipe for bingeing behavior. At the beginning and end of the experiment, the experimenters measured the rats’ behavior and dopamine levels in their brains.
Over the course of the experiment, the rats increased the amount they ate, and the levels of dopamine rose drastically. They suffered from anxiety and other withdrawal symptoms when they were deprived of the sugar. They also had lower levels of acetylcholine, another neurotransmitter that tells the brain that it has had enough. This is classic “addict” behavior: bingeing, excess dopamine, insufficient satiation mechanisms which would normally make one stop eating, and withdrawal.
What does this mean for us? According to one of the experimenters, “The problem isn’t the sugar itself – it’s the eating behaviors. It’s fine to have a little sugar every day, but you don’t want to restrict your intake during the day and then binge during dessert.”* So don’t worry – you don’t have to give up your favorite tasty treats. The next time that tray of cookies is calling your name, you can answer it – but be sure to only grab one, and save the rest for later.