If you're like me then you're currently preoccupied with getting rid of the evidence of the past weeks' excesses that's hanging over your waist band. Your appetite and penchant for high-fat treats seems to have grown-who wants to eat an orange when there's turtle cheesecake in the fridge?! And what are you supposed to do with the boxes of chocolates your evil friends gave you? Not to mention you're trying to maintain a festive mood-just last night you went out for burritos and margaritas with your friends and tomorrow you're going out again. Maybe you'll get that nasty stomach bug that's going around....? No you can't think that, you know what kind of bad karma it is to wish illness upon yourself.
Kaynahorah to the evil eye for a moment and I'll tell you that if you were to get that stomach bug after last night's feast of burritos, in addition to dropping a few pounds you'd be easily able to resist Mexican savors for quite a while to come. The reason is due to the phenomenon of "learned taste aversion", being sick to your stomach after consuming a distinctively scented/flavored food will make you steer clear of the scent of that food for a long time to come. This instant form of smell conditioning is highly adaptive. Food consumption and gastric distress are physiologically linked and even if there is no true causal connection between last night's burritos and your stomach flu, we are wired to immediately learn to avoid the scent involved in that consumption connection. We wouldn't survive long if we were continually poisoning ourselves on the same deadly mushrooms.
Conditioning is also at the root of one way to stay the temptation of fattening delights. In a study done at St George's Hospital in London in 2000 researchers found that dieters who wore a vanilla scented patch, compared to a lemon patch or no patch, lost more weight. The reason they lost more weight than the other dieters was because their cravings for sweet foods were reduced. The sweet aroma of vanilla was able to satisfy their desire for pastries and chocolates and so they were less likely to get their hands caught in the cookie jar.
Vanilla smells sweet because it is always experienced in conjunction with sweet taste and sweet tastes are inherently pleasurable. Put a drop of sugar on a newborn's tongue and you'll see her smile. Sweetness is a hardwired signal for carbohydrates and carbohydrates are necessary for our survival. Moreover, from early childhood on we are given sweets as treats and rewards, both of which are powerful happy elicitors. Thus through our conditioning history of vanilla scent with the positive force of sweetness, we can get a pleasure hit from its aroma without the calories. But this only works if you aren't hungry. There is considerable evidence that food aromas stimulate our appetite even if we're only mildly peckish. Cinnabon kiosks that pump out their hypnotically enticing aroma are preying on just that state. And beware claims that the scents of green apple or peppermint will make you shed pounds. There is no experimental data to support these outcomes and it doesn't make sense from either a conditioning or physiological perspective that these aromas would have any effect.
If you've just had a satisfying low calorie lunch, and you're someone whose sins err on the side of cupcakes, sniffing vanilla can truly help you from dipping into the donuts at work. But if you're more drawn to burritos and french fries you're out of luck. Although sniffing your favorite savory snacks might help quell a momentary urge it is unlikely to be as effective as vanilla aroma because the inherent pleasure hit from savory is less direct and powerful than for sweet. So for me and others who are more seduced by nachos than cookies, good old fashioned exercise and restraint are going to have to be the method on order. Declarations of good intentions help, so after I go for my run, I will eat an apple rather than explore an unopened box of chocolates. And after my dinner tonight of salad niçoise I will sniff some sweet vanilla and leave that cheesecake alone.
Rachel Herz is the author of The Scent of Desire and on the faculty at Brown University.
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