As medical doctors fight a growing obesity epidemic, scientists are developing new ways to satisfy our natural cravings for fat and salt.

Sensing is believing

Close your eyes. Imagine biting into a juicy steak or spooning up a dollop of thick, creamy chocolate mousse. Are you salivating yet? You should be. Humans are predisposed to seek out fat and salt.

Today, fast food joints are on every street corner and nearly every shelf of the supermarket pedals fat- and salt-laden foods. With these food options so ubiquitous, is it any wonder that the country is facing an obesity epidemic? By unraveling the science behind how we experience flavor, scientists are producing satisfying and healthful food options.

Biology behind cravings

So why do humans crave fat and salt? Consider for a moment our humble beginnings. Fat is the ultimate source of energy, but it is sorely lacking in the hunter-gatherer diet. For this reason, the body craves fat. Scientists link these cravings to galanin, a neuropeptide and dopamine, which reduce feelings of stress.

The body needs salt for the proper working of muscles and nerves. For this reason, humans are predisposed to seek out salt. The body even developed sensors on the tongue to perceive sources of salt in the environment. As such, salt became a highly sought-after commodity. Like fat, salt is now omnipresent in the daily diet and has been linked to numerous medical maladies, including high blood pressure, heart disease, stroke and even asthma.

Complicating this situation, scientists believe our food preferences are set in place before birth, as early as the first three moths in utero. Breast milk affirms our flavor preferences after birth. How can a person make healthy food choices when genetics drive us to seek out readily available unhealthy foods and we are predisposed to food preferences before we take our first breath?

Sensing flavor

Scientists believe there is a way to have your cake and it too, so to speak. It all lies in the flavor of foods. Scientists are working to develop healthful food options that still appeal to our cravings. They are approaching this conundrum by unraveling the mystery of how we perceive flavor.

Flavor is a delicate interplay between two senses — taste and smell. Taste describes the perception of flavor on the tongue. Everyone learns in elementary school about flavors related to taste — salty, sour, bitter and sweet. A recent addition, umami (think savory) rounds out the list.

Although most people equate flavor with taste, aroma accounts for most of our perception of flavor. Traditionally, the sense of smell describes aroma observed directly through the nose, but this only accounts for a small fraction of how humans perceive the aroma of foods. Most aromas are perceived after the food has been taken into the mouth. The olfactory bulb, an extension of the forebrain set behind the nasal cavity, detects aromas in food. The aroma chemicals interact with receptors in the nose and the mouth, which send a signal to the brain where we perceive flavor.

Engineering flavor

Scientists are now growing cells in the laboratory that exhibit a certain flavor receptor, like sweet or salty. They use these cells to determine what compounds trigger a response. Flavor scientists use this information to develop ingredients to replace fat, salt and sugar. Food industries are using this technique to develop alternative food options to make food more flavorful. Finding alternative methods that quench the craving for fat and salt could make foods, like potato chips, satisfying and healthy.

References

Avena, N. M., Rada, P., & Hoebel, B.G. (2009). Sugar and fat bingeing have notable differences in addictive-like behavior. Journal of Nutrition, 139(3), 623–628. doi: 10.3945/jn.108.097584

Drewnowski, A. (1997). Why do we like fat? Journal of the American Dietetic Association, 97(7), 58-62. doi:10.1016/S0002-8223(97)00732-3

Kurlansky, M. (2002) Salt: A world history. New York, NY: Walker and Co.