In the past few decades, salt and sugar consumption in the U.S. have both increased dramatically. According to the U.S. Department of Agriculture, in 2005 and 2006, the average American devoured around 3,400 mg of salt per day—almost 50 percent more than the recommended daily intake of 2,300 mg. The American Heart Association reports that the typical American man consumes 335 calories’ worth of added sugar each day, and the average woman 230 calories’ worth; nutritional recommendations, meanwhile, advise men to limit their added sugar to 150 calories and women to 100.
There are many reasons for the stubborn presence of salt and sugar in our diets. Both can act as preservatives or rising agents in processed food, and thus far food companies haven’t been able to find good substitutes for those functions. Sugar can lower a food’s freezing point—important when creating ice creams, frozen desserts, and freeze-dried foods—and can stave off staleness in baked goods. Salt has similar preservative properties and also contributes to texture of processed foods, like the stickiness of some doughs.
But amid mounting pressure from the USDA and other government agencies to make healthier processed food, the food industry’s biggest obstacle is still the simple fact that people won’t buy what doesn’t taste good. As an article in the 2013 issue of Food Business Industry News cautioned, failed early efforts to reduce salt and sugar made consumers more averse to labels like “low-salt,” “low-sugar,” and “low-fat.”
The solution, some food scientists believe, may not involve the taste buds at all.
Robert Sobel is the vice president of research and innovation at the flavor company FONA International. In the last few years, he’s been researching ways to use smells to trick our brains into thinking food contains high levels of sugar and salt, even when it doesn’t. Sobel first came across this concept, called “phantom aroma,” in a 2009 article called “Taste, Aroma, and the Brain” in the magazine Perfumer and Flavorist. The term, inspired by the neurophysiological phenomenon of phantom limbs, is the process by which the brain fills in the perception of a certain taste perceptions even when the ingredient may not exist.
We perceive a food’s flavor through a variety of stimulants—taste, of course, but also texture and smell. There’s a lot that’s still unknown about the neuroscience of taste, but the current prevailing theory is that we take in taste through the gustatory nerve and smells through the olfactory nerve, and information from both receptors combines in the orbital frontal cortex. In addition, past research has shown that we learn to associate certain smells with certain tastes—we associate the strawberry aroma with sweetness, for example, and lemon aroma with sourness.
So what happens when we smell something but don’t taste it? In one 2009 study, French researchers found that when participants ate something treated with a salt-associated aroma (like the smell of ham), they perceived that the food had more salt in it. The researchers theorized that when the brain has a learned perception of a certain type of food, it fills in for the missing taste on its own. “When you are tasting food you are perceiving several sensory dimensions—smell, taste, texture—and the brain is making a synesthetic perception,” said Thierry Thomas-Danguin, one of the study authors and a flavor scientist at the French National Institute for Agricultural Research. “When you are exposed to one dimension, your brain is reconstructing all the flavors and all the sensory dimensions, even if they aren’t there.”