For some people, getting hooked on super-tasty food — sugary soda and ice cream, salty french fries and pizza — might be partly responsible for their craving, binge eating and weight gain. High levels of sugar, fat and salt, and various flavors and food additives might actually hijack the pathways of the brain in ways that are similar to opiates and other drugs.

The evidence suggests that sugar in particular stimulates a greater release of chemicals in the brain — including dopamine, the “pleasure molecule” — than releases triggered by, say, fruit and vegetables. Over time, the brain’s circuitry might become rewired to produce less dopamine in response to high-calorie, flavor-enhanced foods.

As a result — and possibly in combination with genetics and environmental factors — some people will eat more, attempting to stimulate dopamine production to feel good. That’s similar to what often happens when a person is addicted to alcohol, nicotine or narcotics. “Conceptually, it’s pretty clear that highly palatable foods can have druglike effects in the brain and can cause compulsive overuse and food addiction,” says Mark S. Gold, chairman of the psychiatry department at the University of Florida in Gainesville and author or co-author of many studies on the topic, mostly done with animals.

Activating the brain

Much of the research involving people has focused on brain-imaging studies, according to a recent review co-authored by Nora D. Volkow, director of the National Institute on Drug Abuse.

A 2001 article in which Volkow analyzed dopamine levels in brain scans of obese adults helped to advance the theory that people can be addicted to food.

A more recent article, published online in October 2011 in Current Topics in Behavioral Neurosciences, updates the state of the research. A team led by investigators at the Oregon Research Institute in Eugene noticed that MRI scans of the regions of the brain related to reward and the senses lighted up more in obese girls anticipating a chocolate milkshake than when they were actually drinking it, compared with brain MRIs of leaner girls.

What does that mean? Results seem to suggest that people who find food more exciting are more likely to overeat and gain weight, explains Eric Stice of the Oregon Research Institute. “And the more you eat high-fat or high-sugar foods, the less your brain regions are activated by actual intake of these foods,” he says.

But not everyone is swallowing the theory. Food addiction hasn’t been formally recognized by the American Psychiatric Association. And there’s a lack of objective evidence that the condition contributes greatly to the U.S. obesity epidemic.

Who is addicted?

Indeed, there have been few studies on the prevalence of food addiction. But investigators at Yale University have developed a questionnaire to identify people who show signs of addiction to food that is high in fat and sugar. It can also help to assess the severity and frequency of their symptoms. That research suggests a relatively small percentage of people in a wide range of weight categories might be addicted to food.

The Yale study found that only about 11 percent of normal-weight college students could be considered addicted to food. But a recent German study of 750 people with various body mass indexes who were screened with the Yale questionnaire found that about 38 percent of the obese participants and 14 percent of the overweight ones were addicted to food, according to a November 2011 report in the journal Frontiers in Psychiatry. And so were 10 percent of the underweight participants and 6 percent of the normal-weight ones.

“Is this concept of food and addiction a viable one?” asks Kelly Brownell, director of the Yale Rudd Center for Food Policy and Obesity. “There’s no longer any question about that in my mind.” Brownell says the findings raise issues about marketing and selling potentially addictive foods: “The question is whether there is an addictive process that gets activated by food that affects enough people in a sufficiently strong way to create a public-health menace.”

If you’re concerned that you or someone you care about might be addicted to food or any other substance, consult a health-care provider.

Copyright 2012. Consumers Union of United States Inc.