Preventive Medicine Column
Dr. David L. Katz
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.
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 long-appreciated fact that familiarity is a potent agent of dietary preference goes a long way toward making the case for ‘tolerance.’
But whether or not food is addictive is a lesser question, subordinate to a more important one: why are humans capable of becoming addicted to anything?
The answer is survival. Our nervous and endocrine systems 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.
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 blasé 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 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. Cocaine binds to receptors fashioned for our own endogenous stimulant compounds.
We have some deep insights into the shared pathways of addiction thanks to the ill-fated recent history of the weight loss drug, rimonabant (marketed, albeit briefly, as Accomplia). Rimonabant is an endocannabinoid receptor blocker. Endocannabinoid receptors bind, along with the intrinsic molecules for which they are fashioned, THC– the principal psychoactive compound in marijuana (i.e., cannabis).
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- there was a significant increase in suicides. The US never approved it; the Europeans did, and then withdrew it from the market.
“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 absolutely! (see: http://www.chicagotribune.com/news/watchdog/chi-oreos-specialpackage,0,6758724.special).
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…
Dr. David L. Katz; www.davidkatzmd.com