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Food and Addiction

Posted by tinako on October 17, 2010

Dr. Elissa Epel

I listened to a podcast from the Yale Rudd Center featuring Dr. Elissa Epel, an associate professor of psychiatry at UCSF.  She had the strongest words I’ve heard yet on whether food is addictive, with most researchers saying it might be so but we need more research.

She wonders, Why do people overeat against their will?  The answer her research indicates is that the reward center in our brains is a major driver of what and how much we eat, and is regulated by dopamine and opioids.  The pleasure center lights up when we are engaged in very rewarding activities.

She uses the term “highly palatable,” which means that it doesn’t just taste good, like a delicious crisp salad, but that it tastes amazing, like a hot fudge sundae.  Think fat and sugar.  When rats get highly palatable food, their reward center “goes crazy,” but they habituate so that with continued sugar they start having a normal brain response.  What about people?  With repeated sugar, do we habituate or do we become sensitized, dependent on that level of reward?  She answers that a large proportion of people seem to be wired to become highly dependent on highly palatable food, so that they go through hedonic withdrawl when they eat less of that food.  They feel terrible.  She gave as an example Morgan Spurlock’s description in Supersize Me of how he felt after five hours without McDonald’s food: he was nauseous and shaky, which Dr. Epel said was consistent with opioid withdrawl.  Highly palatable food and drugs of abuse use the same neural pathways.

Why is sugar picked on so much?  Just because it’s studied so much?  No, she answers, sugar has special properties in the brain.

She explained that lower animals without much cortex are well-calibrated to keep homeostasis and only eat the calories they need.  Human brains are not good at detecting how many calories we need, and the reward system can completely override those delicate signals of satiety.

Another thing she brought up was that severe dieting, forcing ourselves to not eat something, such as sugar, sensitizes the reward system even more and leads almost inevitably to bingeing, massive overeating.  Stress is involved as well.  She mentioned an experiment wherein rats were given oreos, which were then withheld.  If you then return the oreos, the rats don’t overeat unless stress is added as well.  Also they will not binge if you block the opioids (probably surgically or pharmaceutically).

Here is where she starts getting more concrete about whether food is addictive.  She mentioned that she has met people whose described relationship to food sounds exactly like drug addiction.  It runs their lives.  These are probably a statistical minority, but she says there are lower levels of addiction.  She mentioned families who at the insistence of a nutritionist give their best effort to stop drinking sugary soda, and they are unable to do so.  This is a food dependence on a spectrum with addiction.

She mentions a study in which they found that about 50% of obese people and 20% of lean people have no sense of satiety.  They never feel like they have eaten enough.  She says the toxic food environment is the number one driver of this satiety failure, and stress exacerbates it.

If food is addictive, what are the implications?  Her answer is that Just Say No to the doughnut on your desk does not and will not work.  We’re steeped in a culture that looks on obesity as a failure of personal control, but our brain is wired so that almost everyone will choose the doughnut, especially if stressed, and especially if trying hard not to eat it.  That restraint is peanuts compared to the strong impulsive drive.  Dr. Epel’s clinical work in helping people develop mindful eating is a weak Band-aid in the face of our toxic food environment.  She says we need food policy to help people, both tax structure and healthy defaults.

Drugs have been described as “hijacking” the brain, running down any reasoned responses.  Could you use that very powerful word to describe food?  Dr. Epel answers, for some people, yes, and for kids, they don’t have those reasoned responses – we have to control the environment for them.  To fail is to set them up for a lifetime of struggle against obesity.

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