Want to know what your brain looks like on sugar? You might think twice about desert after you read what sweet stuff does to your brain function. If you missed part one you may want to read it first!
Not only do sweet foods increase dopamine levels, but over-consumption of sweet foods can actually cause a breakdown in brain chemistry. According to a study published in Nature Neuroscience, “common mechanisms may underlie obesity and drug addiction.” They found that when animals were given a diet of high calorie foods, there was a significant reduction in the activity of their dopamine receptors. This is very similar to the affect that cocaine or heroine has on the brain. What does decreased receptor activity mean? It means that the brain has become tolerant to the dopamine signals. Think about going to a concert. When you first get there, the music seems very loud. But as the concert goes on, you get used to the noise level, and it no longer seems as loud as it did when the band started playing. That is what happens with dopamine in the brain. If you are constantly eating or seeing sweet, high-calorie foods, your dopamine levels are always high, just like the music at the concert is always loud. Your brains gets used to the high dopamine levels and starts tuning them out. The signal does not seem as strong anymore.
For someone with constantly high dopamine levels, they will have to eat a lot more sweet, high-calorie foods to get the same kind of pleasure from them as someone who doesn’t indulge in these kinds of foods so often. For some people, this could mean that when they see a high-calorie food or think about eating a high-calorie food, they have an expectation of that food bringing them a lot of pleasure. Then when they eat the food, they aren’t as satisfied as they expected to be, so they eat more. And more. So it is a cycle of constantly elevated dopamine.
Studies have shown that people with addictive-like eating behaviors have greater brain activity in regions associated with substance dependance. They have more activity going on with their reward circuitry and less activity going on with inhibitory regions of the brain. Their reward systems are being triggered at a higher rate than people who don’t have addictive-like eating behaviors, and they are less able to keep themselves from acting on their desires.
Some professionals have questioned whether sugar addiction, and addictive behavior in general, is due more to willpower or genetics. We know that there is a decreased number of dopamine receptors in the brain in both drug addicts and in obese people. The question is whether the decreased number is due to the brain trying to compensate for the abnormally high levels of dopamine or just because those people were born with lower levels of receptors. Some professionals believe that addicts are born with a low pleasure gene. That they naturally have a decreased number of dopamine receptors, so they require more stimulation than the average person to feel the same amount of pleasure, putting them at greater risk for addictive behaviors. There has been evidence though, that the more obese a person is, the fewer receptors they have. This seems to suggest that the brain is trying to compensate. Maybe they were born with fewer receptors to begin with, but it also seems that the brain is adapting as well.
Researches at Princeton University conducted a study on rats who were given a high sugar diet. Brain tests revealed that the rat’s brains actually did adapt to the higher levels of dopamine; they had reduced numbers of dopamine receptors. The study also showed evidence of craving and relapse with sugar. Once the rats had gotten used to the high sugar diet, they worked harder to get to the sugary food, and they ate more of it when they got it. Researchers think that the changes in brain chemistry are responsible for destructive behavior that happens when a person is in withdrawal.
Even with this evidence of the existence of sugar addiction, there are professionals who disagree. Naysayers argue that proof of addiction remains inconclusive; that we need glucose (sugar) to function properly, and you can’t be addicted to something you need to survive. Other professionals say that the animal models from which much of the evidence originates don’t correlate with human eating patterns. They also argue that socio-economic status and psychological factors need to be addressed.
Check back for Part 3 on how you can overcome your sugar addiction…
Sources:
- “Can sugar be addictive?” foodnavigator.com. William Reed Business Media, 16 Jan. 2006.
- Leutwyler Ozelli, Kristin. “This is your brain on food.” Scientific American Sep. 2007: 84-85.
- Daniells, Stephen. “Food addiction: Fat may rewire brain like hard drugs.” foodnavigator.com. William Reed Business Media, 29 Mar. 2010.
- Gardner, Amanda. “Compulsive Eaters May Have ‘Food Addiction,’ Study Finds.” healthday.com. HealthDay, 4 Apr. 2011.
- Gray, Nathan. “Food addiction has similar brain response to drug addiction: Study.” foodnavigator.com. William Reed Business Media, 5 Apr. 2011.
- Hyman, Mark MD. “Stopping Addiction to Sugar: Willpower or Genetics?”
- Scott-Thomas, Caroline. “Animal study suggests existence of sugar addiction, says scientist.” foodnavigator.com. William Reed Business Media, 11 Dec. 2008.
- Scott-Thomas, Caroline. “Sugar addiction ‘unlikely in humans,’ says scientist.” foodnavigator.com. William Reed Business Media, 9 Jan. 2009.
