Remember Lay’s Potato Chips’ classic slogan “Bet you can’t have just one” and Pringles’ “Once you pop, you can’t stop”? They’re fun, sure, but for so-called food addicts, those taglines might mean more than just a catchy advertising scheme. Research suggests there are strong similarities between food and drug addictions — and that it might be just as hard for a binger to put down the pizza as it is for a drug addict to avoid the next fix. In fact, one new study points to food addiction as one of the potential causes of the global obesity epidemic.
What's the deal?
The newest insight comes from addiction expert Fancesco Leri in a study presented at the 2013 meeting of the Canadian Association for Neuroscience. The study found that high-fructose corn syrup and other foods unnaturally high in sugar, fat, and taste enhancers can cause similar behavioural reactions in rats as those caused by hard drugs, including cocaine. So how's that relate to humans? Here's how Dr. Leri explains it: Increased global access to fatty, sugary foods could partially explain the growing number of obese people worldwide. However, increased availablity does not explain why some people are obese and some aren't. Studies on cocaine use indicate that while many people try the dug, only a small fraction become addicted. The same principle could be true for junk food.
In another study, researchers looked at what happened when a bunch of mice were fed high-fat foods for six weeks before going back to a normal diet Adaptations in brain reward circuitry underlie palatable food cravings and anxiety induced by high-fat diet withdrawal. Sharma, S., Fernandes, M.F., Fulton, S. CRCHUM and Montreal Diabetes Research Centre; Department of Nutrition, Faculty of Medicine, Université de Montreal, Montreal, Quebec, Canada. International Journal of Obesity 2012. . The mice weren’t obese (just chubby: they gained about 11 percent of their body weight), but their palates had gotten used to eating the rodent equivalent of Twinkies for every meal. When half the mice went back on a low-fat diet (kale, anyone?) they experienced severe withdrawal symptoms, inlcuding anxiety and intense cravings. Even more interesting: The rats’ brains showed similar activity as rodents going through withdrawal from hard drugs such as cocaine. Specifically, the addicted mice’s brains showed higher levels of dopamine and the molecule CREB, both important to food cravings and drug addictions.
Additional research also suggests that refined carbohudrates may also lead to more intense food cravings and overeating. One study published in June 2013 found that these fast-digesting carbs can trigger the same regions of the brain that control cravings and addiction. (Though the study's small sample size and limiting characteristsics — 12 subjects, all overweight men — should be noted.)
Why It Matters
Food addiction can be just as powerful in real, live human beings Dopamine D2 receptors in addiction-like reward dysfunction and compulsive eating in obese rats. Johnson, P.M., Kenny, P.J. Laboratory of Behavioral and Molecular Neuroscience, Department of Molecular Therapeutics, The Scripps Research Institute-Scripps Florida, Jupiter, Florida. Nature Neuroscience 2010 May;13(5):635-41. . In one study, researchers examined the brain activity of 48 healthy women while they looked at and then tasted a chocolate milkshake Neural Correlates of Food Addiction. Gearhardt, AN., Yokum, S., Orr, PT., et al. New Haven, Connecticut/University of Texas, Austin/Arizona State University, Tempe. Archives of General Psychiatry 2011;68(8):808-16. . Those with higher potential to develop food addiction showed heightened anticipation in the brain upon seeing food, yet their brains did not recognize satisfaction after trying to fulfill cravings. This leads to overeating in an attempt to fill that desire, a thought process that’s nearly identical to the brain activity of alcoholics when shown a stiff cocktail Neural Correlates of Food Addiction. Gearhardt, AN., Yokum, S., Orr, PT., et al. New Haven, Connecticut/University of Texas, Austin/Arizona State University, Tempe. Archives of General Psychiatry 2011;68(8):808-16. .
Other research offers further evidence that food addiction is just as much a clinical disorder as drug addiction. One study suggests that food addicts experience a higher incidence of depression and symptoms of attention-deficit/hyperactivity disorder Evidence that 'food addiction' is a valid phenotype of obesity. Davis, C., Curtis, C., Levitan, R.D., et al. Faculty of Health, York University, Toronto, Ontario, Canada. Appetite 2011; 57(3):711-7. . Some people, unfortunately, might not have as much choice anymore when it comes to those Lay’s and Pringles taglines.
Updated May 2013 by Kate Morin.