Intriguing study findings begin to explain how and why it’s so hard to be good.
By Jack Challem
There’s nothing quite like the satisfaction of biting into a freshly-baked cookie, a chocolate truffle, your favorite kind of ice cream — whatever confection you find most heavenly. Perhaps you get the same kind of “high” from a slice of cheesy pizza with a perfect, chewy crust. Unfortunately, cravings for these foods, and our inability to have just a bite and then stop, can sabotage the best efforts to lose weight and control blood sugar. You may hear someone jokingly say, “I can’t help it. I am totally addicted to Reese’s® Peanut Butter Cups.” What if it’s not a joke? Could food addiction be real?
“Hi, my name is Susie and I’m a sugar-holic.”
The “high” from eating certain foods can lead to compulsive overeating comparable to alcohol binges. When does a strong desire to eat something cross the line from a simple craving to a food addiction? It could be when that desire is so overwhelming there no longer seems to be a choice (i.e., to eat or not eat). Other signs: using food to “feel better" and regularly eating when you’re not hungry.
Simon Thornley, Ph.D., a researcher at the Auckland Regional Public Health Service in New Zealand, recently made the argument that high-glycemic foods (sugary treats, white bread, potatoes) tend to be more addictive than low-glycemic foods (protein foods, legumes, some whole grains, green vegetables). On the other hand, you don’t often hear people having overpowering cravings for salmon or Cobb salads.
Writing in the November 2008 issue of Medical Hypotheses, Thornley made striking comparisons between food addiction and tobacco addiction. Both are often characterized by the following:
1. consuming increasing amounts over time,
2. difficulty cutting back,
3. loss of control, and
4. withdrawal symptoms.
Thornley cites research showing that both addictive drugs and foods can affect neurotransmitters, the brain chemicals that regulate mood. Chief among these neurotransmitters is dopamine, which can create the “high” feeling associated with drug use, sex, and even shopping.
Doped Up with Dopamine
As reported in a 2008 issue of the journal Obesity, researchers have found that when rats binge on sugar, it triggers the release of dopamine in the brain in just the same way that cocaine does.
This research also showed that rats are more likely to gain weight eating a diet heavy in sweets and fats, compared with the same amounts of whole foods. Furthermore, binging on sugar and then fasting afterward leads to neurotransmitter changes that result in increased anxiety. When more sugar is given, it reduces that anxiety and, not surprisingly, the animals turn into “sugar-holics.”
You may be one of those people who can do without cakes and candy but daydream about being able to eat all you want of things like bread or ice cream. Interestingly, other research shows that proteins in both wheat and dairy contain trace amounts of opioids, which are chemically related to narcotics (think heroin, morphine, Vicodin). Although the amounts of these addictive substances are minute, they could conceivably explain part of the power of food addiction.
So, how can you beat a food addiction?
If high-glycemic foods tend to be addictive, the antidote may be low-glycemic foods, which have a moderate effect on blood glucose. Thornley points out that low-glycemic foods may be to sugars and starches what a slow-release nicotine patch is for someone trying to stop smoking. In fact, eating more low-glycemic fare is good advice for anyone, food addicted or not.
1. - Thornley S, McRobbie H, Eyles H, et al. 2008. The obesity epidemic: is glycemic index the key to unlocking a hidden addiction? Med Hypotheses 71:709-714.
2. - Berner LA, Avena NM, Hoebel BG. 2008. Bingeing, self-restriction, and increased body weight in rats with limited access to a sweet-fat diet. Obesity (epub ahead of print) doi:10.1038/oby.2008.328.
3. - Avena NM, Bocarsly ME, Rada P, et al. 2008. After daily bingeing on a sucrose solution, food deprivation induces anxiety and accumbens dopamine/acetylcholine imbalance. Physiol Behav, 93:309-315.
4. - Avena NM, Rada P, Hoebel BG. 2008. Evidence for sugar addiction: behavioral and neurochemical effects of intermittent, excessive sugar intake. Neurosci Biobehav Rev 32:20-39.
5. - Yoshikawa M, Takahashi M, Yang S. 2003. Delta opioid peptides derived from plant proteins. Curr Pharm Des 9:1325-1330.
6. - Meisel H, FitzGerald RJ. 2000. Opioid peptides encrypted in intact milk protein sequences. Br J Nutr 84 Suppl 1:S27-31.
7. - Sakaguchi M, Koseki M, Wakamatsu M, et al. 2003. Effects of beta-casomorphin-5 on passive avoidance response in mice. Biosci Biotechnol Biochem 67:2501-2504.
Reviewed by Susan Weiner, RD, MS, CDE, CDN. 4/11
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I just came back from D-Blog Week. Had a great time. Weather was amazing. Discovered lots of new D-bloggers. When we last left our hero, he was celebrating a fantastic day at the Camden Aquarium. I love, love, loved the luxury of glancing at Dexcom throughout the day as we made our way through the shark tunnel, into the hippopotamus exhibit and when touching squishy sea creatures that looked like a human heart. Blood...