Blog | Wednesday, December 7, 2011

Of course food is addictive! Why is anything else?


There has been an impressive concentration of recent public opinion on the matter of food addiction. Journalists ask if food can be addictive, and academics opine, some to say no, most to say yes, and many to spell out the implications, including legal ramifications for food manufacturers.

midnight snack by VanessaO via Flickr and a Creative Commons licenseBefore we worry about a day in court, though, let's apply our own judgment to the issue, and see where we wind up in the court of public opinion.

When we speak of addiction, we have a tendency to blend the formal definition with the informal implications that matter to us. Formally, definitions range from the very concise, a compulsive dependence, to the long and malleable. Informally, we tend to reserve the term for undesirable behaviors, although that's not truly required. The core elements of addiction are a need for the thing in question, symptoms of withdrawal from the thing, and tolerance to the thing (i.e., the more you get the more you need/want).

We certainly need food, and have withdrawal symptoms from it, ranging from mild hunger to death from starvation. The only potential controversy would involve tolerance, but it has long been clear that taste buds learn to love the foods they are with, and want more of them. The sweeter diets become, the more sugar people tend to prefer. The saltier diets become, the more salt people tend to prefer. The spicier diets become, the more spice people tend to prefer. The long-appreciated fact that familiarity is a potent agent of dietary preference goes a long way toward making the case for "tolerance."

Which then has food firing on all three of addiction's cylinders.

While a reliable definition may be where debates about food addiction begin, it is certainly not where they end. The topic has taken on a thick patina of drama due largely to the technique of "categorization."

I suspect no one would be impressed to learn that while just about all human beings like food, we don't all get exactly the same quantity of pleasure from exactly the same foods. In fact, this statement is just about self-evident and consequently trivial. It isn't much less so to note that those who like food the most may be more prone to weight gain and obesity.

Enter the power of categorization. If we divide people into categories of "more" and "less" sensitive to the pleasures of food, and find a higher prevalence of the "more" sensitives among the overweight, it seems to suggest a great mystery has been resolved. But it's not really all that different from noting that intelligence varies from "less" to "more," and there is a higher concentration of "more" among rocket scientists. Well ... duh.

The technique of categorization tends to add drama to what might otherwise be mundane. We are unimpressed to know that some people have more sensitive taste buds than others, how could it be otherwise? But categories of taste sensitivity suggest answers to such irrepressible questions as: why me? Change a continuous scale of human attributes to discrete categories, and it sounds as if fate or genes are conspiring against some of us unfairly. Declare that some are "addiction prone" and others not, and again, we have the inequities of unkind fate to deal with.

But in reality, this is garden-variety human variation for the most part. We vary in hair color, eye color, height, running ability, jumping ability, musicality and IQ. We are all a lot alike, but we differ across a range, for every trait we own, including the pleasure we get from food.

Categorization gets in the way of understanding the addictive properties of food. Categories require that some of us be addicted to food, and others not; some vulnerable, others not. This kind of thinking propagates the debate: can food be addictive?

Of course food can be addictive! The real question is: why is anything else (other than sex)?

Whether or not food is addictive is a lesser question, subordinate to a more important one: Why does addiction exist at all? Why are humans capable of becoming addicted to anything?

The answer is survival. Our nervous system and endocrine system evolved to reward us most robustly for behaviors that require real effort, and are required for survival. Getting food has, until quite recently, required real effort, and is of course required for personal survival. Finding a mate is often a labor-intensive undertaking, but is key to the survival of our selfish genes.

Genes are running this show. The humans who happened to have genes that rewarded them most robustly for eating and mating were most apt to eat, mate and survive long enough to pass on the chance to their progeny. Those humans who were blasse about eating and mating never got to progeny.

Food and sex are the reasons variations on the theme of addiction are physiologically possible in the first place. Almost anything else that happens to be addictive is circumstantially hijacking reward systems built for food and sex.

Opiate drugs, like morphine and heroin, are similar to our own endorphins, and bind to receptors that subtend our intrinsic system of reward and reinforcement. The vast annals of narcotic abuse are really just testimony to receptors that don't discriminate adequately among a variety of look-alike compounds.

Cocaine binds to receptors fashioned for our own endogenous stimulant compounds. This system is more about fight and flight than feasting and making whoopee, but the basic concept is the same.

We have some deep insights into the shared pathways of addiction thanks to the ill-fated recent history of what was, for a time, among the most promising of weight-loss drugs, rimonabant (marketed, albeit briefly, as Accomplia). Rimonabant is an endocannabinoid receptor blocker. Look carefully at that long and clumsy word, and you will see something resembling "cannabis" in the middle. That's no mistake. Endocannabinoid receptors bind, along with the intrinsic molecules for which they are fashioned, THC, the principal psychoactive compound in marijuana.

Rimonabant helped curtail over-eating (and thus facilitated weight loss), and also appeared to be effective at curtailing use of pot, tobacco, and possibly even alcohol. The same receptors were playing a role in a whole panoply of addictions. Alas for rimonabant and those who took it, its effects were not entirely benign. Its use was associated with a significant increase in suicides. The U.S. never approved it; the Europeans did, and then withdrew it from the market.

There is a larger context here in which we ask the lesser question about food addiction while skipping the greater. We do that in general. We ask "Should we legalize marijuana for medical use?" without asking: On what basis, in general, should drugs be permissible for medical use? We might at least grapple with the fact that medical cocaine is already legal, as are close-cousins to heroin that are substantially more potent. In this context, the long debate about marijuana seems (and frankly is) downright silly.

We foster an unending, insoluble debate about abortion, but never deal definitively with either the sanctity of life, or autonomy. If the sanctity of life is a decisive argument against abortion, how does our society sanction capital punishment? And if autonomy is the decisive argument for the right of choice, on what basis is assisted suicide denied as a choice to an adult who can find no further purpose, comfort, or dignity in life, and would like to go gentle into that good night?

There are innumerable other examples, but I digress. Let's just leave it at this: the answers we get will never be better than the questions we ask.

"Can food be addictive?" is at best a rather trivial question. Food is on the very short list of reasons addiction is physiologically possible. Food, and sex, are why addiction exists.

Given this, some very interesting questions follow logically. How much does the food industry know about the addictive properties of food, and have they willfully used such knowledge to influence what, and how much, we eat? A stunning expose in the Chicago Tribune, published serially between August 2005 and January 2006, indicates quite clearly that the answers are: a lot, and hell yeah!

Stated differently, when they told us "Betcha can't eat just one!" they had done their homework, and knew they could back it up. They came, as the saying goes, loaded for bear.

Another interesting question that follows from the irrefutable addictiveness of food and the almost equally irrefutable food industry exploitations of that vulnerability is, what do we do now? Public policy responses are being debated. Tactics for self-defense encompassing, but not limited to, environmental cues, food volume, flavor variety and food simplicity are all up for grabs.

Choosing among such answers, and/or combining them artfully, constitutes a very worthy topic in its own right. I promise to address it soon.

For now, my mission was less about the answers and more about getting the questions right. Besides, I'm off to the kitchen; I need a fix ...

David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.