There are always new studies coming out about why people eat junk food. Or rather, the studies tend to be about the effects high-fat foods have on other creatures, like rats and mice; from these effects, we try to extrapolate possible causes of human predilections for junk food. The most recent of these, as reported in the Huffington Post, noticed that mice fed a high-fat diet exhibited brain chemistry similar to that produced by depression; when their diet was changed, the fat-fed mice appeared to be more anxious and sensitive to stress than those in the study’s control group. These effects suggest a cycle: the poor mice suffered depression-like symptoms while eating their junky diet, and withdrawal-like symptoms when returned to healthier food.
The suggestive allusion to the cycle of addiction reminds me of similar research released in 2009. This earlier study fed rats high-fat foods and measured their response in two ways: In one test, the rats were given a means to electronically stimulate the pleasure centers of their own brains; in another test, the rats were dissuaded from eating high-fat food through the administration of electrical shocks. In the first test, fat-fed rats stimulated their brain’s pleasure centers for longer than control-group rats, leading researchers to conclude that they were desensitized and required more stimulation to feel pleasure (a “hallmark” of addiction, according to the article). In the second, the fat-fed rats simply ignored the electrical shock and ate the junk food anyway.
The temptation to anthropomorphize or even identify with these creatures is strong. The image of a rat gnawing on cheesecake or sausage despite the electrical zap is a painful thought; most of us are acquainted with some experience of doing what we know is bad for us. The act of eating “junk” — foods that are high in fat or sugar, which we do need in some quantity, but low in other nutrients — is certainly cast as a bad habit in conventional conversation. Think how many times you hear “Oh, I shouldn’t” or “This is bad” during the holidays, when sweet gifts and rich meals are part of the seasonal celebration. Even at less food-focused times of year, it’s common to cast an appetite for junky food as an “addiction,” as though the appetite resists will and control, even if this is not true in a particular instance. It’s a story we commonly tell ourselves.
It’s the story that began the research, too; before the above cited studies had their results or made their claims, they began with the premise that high-fat foods might have addictive properties. Even so, the addiction theory is still just a theory: Though there are many similarities between human and rodent brains, the analogy between their behavior and ours is hardly perfect. And though brain science provides a fascinating window into the patterns of the mind, it still doesn’t answer why we eat junk food even when we think of it as “bad.” The studies above are suggestive of possible explanations, but pushing at that explanation will lead to a chicken-or-egg argument: Is desire or appetite caused by neurons firing, or vice versa? In either case, what initiates the cycle? These questions are as yet unanswerable. And though the story of the rats painfully addicted to high-fat food may be a true story about rats, it is compelling to us because it resonates with stories we already tell about ourselves (which may or may not be true).
It’s the story I want to discuss here, not the actual experience of addiction (a subject that should be treated with more seriousness and expertise than I’m equipped to do). After all, the addicted mice and rats were living under unusual and extreme conditions; most of us have a much more casual relationship with junk food. Casually, we might invoke the idea of addictive substance to describe experiences that a great many people have but that aren’t considered seemly: accidentally eating an entire bag of chips, wanting a second or third piece of cake, that sort of thing. It’s a distancing technique: When we joke about being addicted to chocolate, we play on the idea that our bodies are acting without full permission of the minds, or that the pull of the sweets are simply too strong to be resisted.
At first glance, this sounds like the opposite of what I was describing when I wrote in an earlier piece about eating as an aesthetic experience. Food can invoke complex cognitive faculties such as judgment, memory, and complex associations; eating can be a self-affirming act, allowing the eater to feel his or her mind thinking, judging, remembering, or enjoying. Do these faculties disappear when the foods contain a lot of calories?
One thing that might be said broadly about junk food is that it supplies a simpler and often a stronger sensory impression than the food we eat for sustenance. The snacks we put out at parties and the treats we make for our loved ones over the holidays tend to be very sweet or very salty, very strongly scented with mint or vanilla or very coated with potato chip seasoning. When we taste something like this, aesthetic judgment is simple: you like it (or dislike it), and since the flavor tends to be intense, you probably like it a lot (or dislike it a lot). That makes for a simpler eating experience; the times that we reach for junk (for a quick snack after a long day, for comfort in emotional turmoil, for fun during a movie or party) are no times to be teasing out complexities with the tongue and contemplating the high and low notes of artificial flavoring. So perhaps junk food does offer a sort of self-effacement or understandable reprieve from thoughtful, engaged eating.
But of course it’s never so simple. The exaggerated, primary flavors of junk food might seem to dominate the senses and aesthetic faculties, but like any other food, junk is still embedded in a complex web of cultural connotations, social relationships, and other meanings. The winter holidays are particularly emblematic of that. Why would we bake so many cookies if not to wish sweetness upon our friends and family? Why would we pour bowls of chips and pretzels at the holiday party if not to encourage our communities to share simple pleasures? Why plan a big, rich holiday feast so soon after Thanksgiving? We can choose not to partake, of course, or we can choose to celebrate with variations that are better suited to our individual constitutions and food allergies. Or we may, like the mice, experience physiological effects from eating high-fat and high-sugar foods that cause us to seek it out for nonseasonal reasons. But the brain and body chemistry is inextricably enmeshed with our cultural rituals of sharing and our personal memories of favorite treats. (Even the workplace gnashing about how bad we are to enjoy all the office candy is a kind of relationship building.)
Our relationships with food are always complex, always entangled, always allusive. It’s understandable if we want to forget that from time to time, but the stories we tell about food should not. • 11 January 2013