New evidence links the brain’s pleasure center and biological clock to snacking, according to an article published in Science Daily. High-calorie foods are linked to disrupting our body’s natural feeding schedules, leading to overeating and obesity. Dopamine is a key element of the findings.
The recently published study suggested a link between several, separate parts of the brain and linked them to overeating and obesity. “The pleasure center of the brain that produces the chemical dopamine, and the brain’s separate biological clock that regulates daily physiological rhythms, are linked, and high-calorie foods—which bring pleasure—disrupt normal feeding schedules, resulting in overconsumption,” the article said.
It should come as no surprise that we derive pleasure from eating high-calorie and high-fat foods, but the causal link between such a diet and dopamine levels in the body provides a solid foundation for proving those claims.
The Straight Dopamine
Making sense of this study requires a working knowledge of dopamine, a neurotransmitter found in the human body. So what is it and how do we get it?
“Dopamine is commonly referred to as the ‘feel-good chemical,’ due to a pathway called the mesolimbic dopamine system—the most important reward pathway in the brain,” said Dr. Kevin Ahern, Professor of Biochemistry and Biophysics at Oregon State University. “Dopamine’s normal function is to make you associate good feelings with things like eating, sex, and social interactions, necessary for survival and reproduction, so that you keep doing them. When you do something good for your survival or propagation of your genes, neurons in your brains mesolimbic dopamine pathway release a little bit of dopamine.”
Dr. Ahern also said that many drugs are closely linked with dopamine release. Amphetamines convince the neurons in our brains to release more dopamine, for example. Nicotine and opioids do the same thing. On the other hand, cocaine inhibits the removal of dopamine from the body’s synaptic cleft. In the context of the new study, with high-calorie foods instigating a dopamine release, they can be substituted in for the illegal substance element of this explanation.
When Enough Isn’t Enough Anymore
With prolonged substance abuse or a prolonged unhealthy diet, the body reacts differently than it did at the onset of the behavior pattern.
“Repeated use of the drug and repeated floods of dopamine stimulate ‘downstream pathways’ and lead to a learning process,” Dr. Ahern said. “Because the amount of drug-induced dopamine is so much larger than the brain’s little spurts, the brain responds by making fewer dopamine receptors, helping to reduce the effects of a flood of dopamine.”
However, the other side of this comes in a form of desensitization. According to Dr. Ahern, this muted level of dopamine reception means the brain no longer responds as sensitively to contact with the drug as it used to, so drug users don’t get the same effect from the same amount of intake.
“Meanwhile, even though the drug may no longer provide the pleasure it did, drug craving then begins in the rewired brain, leaving the user unsuccessfully trying to achieve the original high,” he said. “Meanwhile the normal, smaller elevations of dopamine from everyday feel-good activities no longer satisfy.”
While studies are still being formed, it’s possible that a similar rewiring of the brain and desensitizing to stimulus may come from high-calorie foods—especially those eaten between meals—leaving us craving more and more.
Dr. Kevin Ahern contributed to this article. Dr. Ahern is a Professor of Biochemistry and Biophysics at Oregon State University (OSU), where he also received his Ph.D. in Biochemistry and Biophysics. He has served on the OSU faculty in Biochemistry/Biophysics since the mid-1990s.