Almost monthly, new research confirms that food can cause drug-like brain changes. Food and sex are known as "natural reinforcers." That is, they aren't drugs, but our brains light up for them so we reach for more without thinking.
Still, the concept that food can cause obesity because it is like a drug is perplexing. After all, our rather buff ancestors ate a lot, and quite evidently were enthusiastic about sex. Yet becoming dangerously hooked didn't seem to be much of a risk. Didn't their brains light up for food and sex? Yes, of course. The difference is that they weren't surrounded by super-stimulating, synthetic versions of food and sex. We are, and it is a relatively recent hazard.
Think about it. How many of your ancestors had easy access to tasty munchies that were ready-to-eat, available cheaply in endless variety, and carefully laced with fat, sugar and salt to keep them coming back for more? How many had computers on which they could click to an unending stream of hyper-stimulating erotic videos, featuring real, novel mates, writhing with desire (perceived by a primitive part of the brain as genetic opportunities) -- and, when appetite flagged, a cornucopia of ever kinkier videos?
Pornography? It's a new synaptic pathway. You wake up in the morning, open a thumbnail page, and it leads to a Pandora's box of visuals. There have probably been days when I saw 300 vaginas before I got out of bed.--John Mayer, musician
The extreme stimulation of today's enticements can hijack our brains. There's no way John Mayer would view the same vagina 300 times before rising if, say, he only had a porn magazine, or even a woman. Constant novelty-plus-erotica is riveting. His brain releases more dopamine with each new image, even as it shuts down key nerve cell receptors (to drive him to binge). He is tricked into valuing his pussy panorama even above 3D stimuli.
PLAYBOY: You'd rather jerk off to an ex-girlfriend than meet someone new?
MAYER: Yeah ... Internet pornography has absolutely changed my generation's expectations. How could you be constantly synthesizing an orgasm based on dozens of shots? You're looking for the one ... out of 100 you swear is going to be the one you finish to, and you still don't finish. Twenty seconds ago you thought that photo was the hottest thing you ever saw, but you throw it back and continue your shot hunt and continue to make yourself late for work. How does that not affect the psychology of having a relationship with somebody? It's got to.
This is how food and sex, which throughout evolution have generally contributed to our well-being and led naturally to warm feelings of satiety, morph into drug-like and addictive super stimuli that don't. When we plunge in, we fall for enticements that are not especially valuable and sometimes risky. Not only can they steal our attention from soothing connections with real people (and nutritional food), they can actually hook us.
Who's at risk for addiction to natural reinforcers?
Most addiction research focuses on substance abuse, not addiction to natural reinforcers. It reveals that only a minority of us ("novelty-seekers" and "impulsives") are genetically susceptible to substance abuse, due to low dopamine receptors in different regions of the brain's reward circuitry. (Dopamine is the "Gotta get it!" neurochemical, and the reward circuitry is the brain pathway that drives all appetites and motivation.)
So, are the rest of us safe from addiction? When it comes to substance abuse, perhaps yes. Yet when it comes to unrestricted access to super stimulating natural reinforcers, the answer may be no, although certainly not everyone gets hooked. The reason hyper-stimulating versions of food and sex can hook us -- even if we're not otherwise susceptible to addiction -- is that our reward circuitry evolved to drive us toward food and sex, not drugs.
Take food. If you binge on hyper-stimulating foods (say, concentrated fat and refined sugar) it can cause changes that resemble the brain changes seen in substance abusers. This happens in rats, too, and not just in the novelty-seeking, impulsive minority. Nearly all the animals that were offered unrestricted access to goodies like bacon, sausage, cheesecake, pound cake, Ding Dongs and frosting couldn't stop binging and became obese.
Almost immediately, dopamine receptors dropped in their brains, which drove the rats to binge, and ensured they would later experience less stimulation from normal chow. Other changes, such as a numbed pleasure response, worsened over time. Two weeks after scientists returned them to rat chow, the rats' brains still hadn't recovered. In fact, when confronted with a diet of normal chow, they chose to starve for a time rather than eat it. (Full study)
It makes sense for mammals to have a built-in mechanism that can override feelings of satiety. They must "get it while the getting is good": storing calories when fruit is ripe, gorging before hibernation, swallowing a kill before the competition shows up and so forth.
"Not found in nature"
The binge-to-obesity phenomenon, however, doesn't show up unless mammals, including humans, shift to diets that don't exist in nature -- unrestricted starches and sugars.
Although obesity has been increasing among all Americans in recent decades, it has skyrocketed on Indian reservations since the 1960's. The [starchy] commodity and fast food diet is the opposite of what Indians ate until recent generations: ... [In contrast,] high protein and saturated fat food [bison, elk, antelope, deer, with some berries, nuts and roots] seemed to serve the tribe well.
Native Americans aren't the only ones bulging, however. Nearly two-thirds of most Westerners are overweight, and over 30 percent of Americans obese. This is especially telling because, unlike rats, we care about our waistlines, which keeps some of us in check even in the face of severe temptation.
The regions of the brain that change in response to super stimulating food also govern sexual appetite. So, are today's sexual super stimuli, like today's junk food, causing drug-like changes in the brain's reward circuitry? They certainly constitute a sexual diet not found in nature.
So far, no one seems to be able to do the necessary (brain) research. However, the symptoms heavy porn users complain of could logically be explained by the same brain changes observed in rats with unrestricted access to super-goodies. (Incidentally, rats and humans are distant relatives, and share the same primitive brain mechanisms for appetite and addiction.)
Just as rats binge on exciting food, porn users often binge on porn. Many users report that they are unable to stop or control their viewing, not unlike Sooty the guinea pig, who "got it while the getting was good" when he broke into a cage full of females.
Users also frequently notice numbed sensitivity to pleasure (probably from lower dopamine receptors), which shows up as skyrocketing libido, that is, a need for more frequent stimulation (more dopamine) to self-medicate restlessness or anxiety. Often they require more extreme material to achieve climax, develop erectile dysfunction, or discover that sex with a willing partner doesn't satisfy them (leading back to supplemental, or perhaps exclusive) porn use.
Heavy users also sometimes report obsessive-compulsive behaviors, depression, severe stress at the thought of socializing and concentration problems. And users who try to stop viewing porn report lingering withdrawal symptoms such as shaking, insomnia, mood swings, splitting headaches, anxiety, depression, lethargy, foggy thinking, stomach pains, disturbing dreams, flu-like symptoms and a strong desire to strangle someone. These symptoms suggest that their brains are indeed struggling with brain changes common to addiction. Porn recovery sites are springing up all over the Web.
Here's the key point: Most people don't abuse substances because they haven't tried them, don't get much of a buzz, or find the effects aversive. But who doesn't like sweets or sexual arousal? And who doesn't like an especially tempting treat or hyper-arousing visual -- especially if his brain's pleasure response is numb from over-stimulation? Our brains are more vulnerable than we currently believe.
When does a stimulus put us at risk for slipping into excess?
Danger lurks when something:
- registers as an especially valuable version of a thing that our ancestors (and we) evolved to find irresistible
- is available conveniently in limitless supply (not found in nature),
- comes in lots of varieties (novelty)
- we binge without realizing it is triggering brain changes.
As we've seen, junk food fits this model. So does free Internet porn. Yet porn poses unique risks. Food sets limits on consumption: stomach capacity and the natural aversion that kicks when we can't face one more bite of something. But there are no physical limits on Internet porn consumption, other than the need for sleep and bathroom breaks. One can "edge" to porn for hours without climaxing and without satiety or aversion kicking in ... hours of supranormal neurochemical stimulation of the appetite mechanisms of the brain. Each click to a novel video "violates our expectations" with something new and exciting, releasing more and more dopamine into the brain.
Intense arousal produces a more exciting buzz of neurochemicals than cheesecake -- one that is therefore more reinforcing. That is, the brain more thoroughly wires together all associated cues, making repetition of the experience in the future more automatic. Moreover, heavy porn use sometimes discourages the user's pursuit of friendly interaction with others, which would help regulate the brain naturally. Also absent are factors that once protected our ancestors against over-stimulation. There are no jealous mates, wise elders, or social taboos, and often no sexual partners with their own ideas. Porn use seems risk-free because it's private and virtual.
Alas, not only are most of us unaware that today's hyper-stimulating sexual goodies can put our brains at risk for the changes associated with addiction, we're also up against a powerful meme in today's culture. It proclaims that, "Any kind of orgasm-promoting behavior is inherently so healthy that we must vigorously deny the growing evidence of the risks inherent in unlimited access to today's sexual super stimuli."
Is this sound thinking? If our brains have evolved to drive us toward food and sex, shouldn't we be a bit more cautious about inundating ourselves with hyper-stimulating versions of them? Already, "about 17 percent of individuals who view porn on the Internet meet criteria for sexual compulsivity. That translates to a lot of people, given that about 12 percent of all the Internet traffic is porn and nearly 90 percent of the young male population (about 30 percent of the young female population) view pornography," says Professor Steven C. Hayes.
Want to understand today's Internet porn phenomenon in biological terms? Visit Your Brain On Porn.