It’s that time of year again:  the holiday candy is drastically discounted, the decorations are back in the attic, and you may be finding yourself carrying a few more pounds than you were before Halloween signaled the start of an entire season dedicated to dietary indulgence. Why is it so much more difficult to stop eating sweet, salty, and rich, fatty foods than to walk away from steamed asparagus or a grilled chicken breast? Obviously, there’s a great deal of social and cultural influence over what you might choose to eat, but you can take comfort in knowing that you may also be genetically programmed to prefer certain flavors over others. 

From an evolutionary perspective, fat and simple carbohydrates were both extremely valuable nutrients. Gram for gram, fat provides over twice the energy of carbohydrates or protein, so the ability to perceive the presence of fat through sensory channels may have offered a kind of survival advantage in environments where constant access to abundant food was not guaranteed. And simple carbs provide a burst of quick energy—a good thing when you might have to outrun a predator. In the modern world, however, where large amounts of fat and carbs are no further away than your pantry or a drive to the grocery store, these sensory strengths can contribute to body fat gain and other health problems. 

There are genetic variations in people’s perceptions of the five primary flavor categories: sweet, salty, bitter, sour, and umami (meaty/savory). Those who are extremely sensitive to certain flavors are called “supertasters,” while others are medium tasters or non-tasters. Studies have shown associations between intensity of taste perception and body mass index (BMI), weight gain over time, and other health markers, including hemoglobin A1c—a measurement of average blood glucose over a few months’ time.   

One study suggested that people with a higher sensitivity to the presence of fat in foods had habitually lower intakes of fat and total calories. Perhaps being better attuned to the fat in food helped those people feel more satisfied, making it easier for them to stop eating after consuming a reasonable amount of food. (Maybe you have a friend who is satisfied after half a cupcake and leaves the other half untouched, while you eat the whole thing and can’t stop thinking about going back for a second one. Genetics may actually be at work here!) 

The reverse applies as well; studies show that people with less than average sensitivity to certain foods might be inclined to consume more of them, until a certain threshold is reached. If you are less sensitive to sweet, sour, salty, or another flavor, more of it will be required for your body to register that you’ve had enough. 

The same principles apply to children. Sometimes fussy children are simply asserting themselves and testing their boundaries, but if they refuse to eat certain vegetables, they might be a supertaster of bitter flavors. This means their taste perception for bitter is very strong, so they will likely not want to consume bitter foods, such as eggplant or dark leafy greens. (Probably why a bit of salad dressing or melted cheese helps these go down with less protest!) 

The studies on perception of taste influencing food preference are interesting, but don’t think any of this absolves you of responsibility for making good food choices. Having preferences for certain foods encoded in your DNA doesn’t mean you have absolutely no control over what you eat. It just explains why making better choices sometimes seems very difficult. It’s tough to go for a grilled salmon Caesar salad when your genes are nagging you to rip open a bag of sour cream and onion potato chips. But it can be done! After all, you fight your biology—and win—every morning when you shut off your alarm and get out of bed, even though every cell inside you wants to pull the covers back up and stay in!