The Science of Willpower

Secrets for self-control without suffering

Sugar Addiction In Your Body, Not Just Your Mind

Is out of sight, out of mind the best policy for temptation?

In my Science of Willpower course at Stanford University, I have a lot of self-proclaimed addicts.

The most common addictions? Sugar, email, and reality TV.

It's easy to dismiss these confessions as exaggerations-can you really be "addicted" to Top Chef?. But a new study shows that sugar, at least, shares an important addicting feature with substances like nicotine or heroin. 

Many addictive substances initially make you feel good by releasing (or blocking reuptake of) substances in the brain that trigger pleasure, euphoria, focus, or energy. But your brain and body are not necessarily interested in sustaining your bliss. They are motivated to keep your systems steady and avoid extremes. Thanks to this drive for homeostasis, your brain and body learn to adapt to the effects of mood- and mind-altering substances.

For example, if a substance would normally trigger a flood of serotonin, your brain may adapt by reducing receptors for this neurotransmitter, or producing less serotonin. And when your brain expects that you are going to take the substance, it may swing in the opposite direction (reduced availability of serotonin) to counteract the expected effects of the drug. This anticipatory drop can create powerful cravings for the substance.

Through this process of adaptation, the addiction cycle is strengthened, and the addict needs the drug just to feel normal. Now it looks like the same process may be happening-at some level-with sugar.

Researchers at the National Institute for Physiological Sciences in Japan were curious how the brain and body might adapt to the expectation of eating something sweet (1). They found that when mice expect a sweet treat, their brains release a chemical called orexin. Orexin triggers the body's muscles to take up whatever sugar is circulating in the bloodstream. In this way, the body is preparing for an expected increase in blood sugar levels. This is a great adaptation if you eat the food, helping to keep blood sugar levels steady.

But what if you decide you want to resist the temptation of the sweets? Then the drop of blood sugar comes with two very unwanted side effects: cravings to eat, and decreased energy to resist. The result? It's much harder to say no, and you may even need to eat to feel normal. Much like the cigarette addict who needs to smoke, or the pain medication addict who needs to take a pill, just to feel normal.

This study is the second this year to suggest that high-fat or high-sugar food can trick the brain and the body into consuming more. That doesn't mean that food should be considered an addiction on par with other substances. But it does make you wonder how else our eating behavior is influenced by biological processes we can't control or even observe.

So what's a sugar addict to do? One solution comes from research on candy consumption. Brian Wansink and colleagues at the University of Illinois, Urbana-Champaign, have demonstrated that when it comes to candy, out of sight is out of mind.

In one study (2), they tracked participants' chocolate consumption in three different situations: 1) chocolates were placed in a closed container on participants' desks (visible and convenient), 2) chocolates were placed inside the participants' desk drawers (still convenient, but now "invisible") and 3) chocolates were placed in a closed container a short distance from participants' desks (invisible and also less convenient).

The researchers found that with decreasing visibility and convenience, participants consumed less chocolate. Even the very small change of putting the chocolates in a drawer led to about 1/3 third less consumption. That's the kind of simple step anyone--even a self-proclaimed sugar addict--can take.

One possible explanation for this study is that seeing the candy kickstarts a cascade of changes in your thoughts, emotions, and yes-your blood sugar-that can make crave and consume.

The solution, then, is to take greater control of your immediate environment. Keep candy on hand if you want, but keep it out of sight. This holiday season, don't leave trays of treats displayed on your dining room table. (Something I learned a few years ago after a Christmas that led to greater cookie consumption than I thought possible.)

And because you can only control so much of your environment, it's worth considering proposals to limit the availability of junk food. For example, another new study (3) shows that replacing junk food with healthier fare in school vending machines and cafeterias led to an overall decrease in kids' junk food consumption.

Many had feared that taking the treats out of school would lead to a rebound effect, driving kids to consume more junk food outside of school. Instead, there was no effect on what they consumed out of school. Out of sight-and out of reach-equaled out of mouth.

Perhaps my self-proclaimed TV-addicted students need to hide their remote in a desk drawer, and the email addicts need to close that gmail window.

Softer addictions may create less suffering that other forms of addiction, but these strategies-get away from your triggers, clean up your environment, and make a fix harder to obtain-aren't too different from those recommended for addictions of any kind. When it comes to temptation and self-control, it's important to remember that we all need all the help we can get.

Studies Cited:
1. Shiuchi T, et al (2009). Hypothalamic orexin stimulates feeding-associated glucose utilization in skeletal muscle via sympathetic nervous system.
Cell Metabolism, 10(6), 466-480.
2. Painter JE, Wansink B, & Hieggelke JB (2002). How visibility and convenience influence candy consumption. Appetite, 38(3), 237-238.
3. Schwartz MB, et al. (2009). The impact of removing snacks of low nutritional value from middle schools. Health Education & Behavior 36(6), 999-1011.

 

 

Kelly McGonigal, Ph.D., is a health psychologist at Stanford University.

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