There has been a lot of speculation that fast food establishments and bakeries intentionally waft smells that attract customers. I’ll admit I find the smell of cheeseburgers quite tempting.
Researchers are seeking to understand what draws humans to the smell of fatty foods in an effort to target those sensations as a way to combat obesity and obesity-related diseases. The approach seems reasonable. If I couldn’t smell a juicy grilled cheeseburger, I wouldn’t get distracted enough to stop and buy one when I had no intention of doing so in the first place.
Taste and smell perception rely on the ability to detect small chemical signals. Taste is also heavily dependent on smell and the brain combines these signals to detect the flavor of foods. Have you ever noticed that nothing tastes quite right when you have a cold or if you lost your sense of smell with Covid?
Why are we as a species so attracted to the smell of fats in particular?
This was the question a recent article published in Physiological Reviews sought to answer. The article mentioned that many proteins are involved in the ability to detect the taste and smell of fats, and two proteins in particular, CD36 and CPR120, are thought to play a big role in our ability to detect fatty acids. In addition, saliva contains enzymes that breakdown fats and contribute to our perception of fatty tastes.
Why is it so hard to resist the smell of fatty foods?
As it turns out, the review identified multiple regions of our brains that are involved in the ability to perceive fat tastes and smells including the somatosensory cortex, insula, dorsal striatum, parabrachial nucleus, nucleus of the solitary tract, nucleus accumbens, hippocampus, thalamus, amygdala, medial prefrontal cortex, cerebellum, hypothalamus, orbitofrontal cortex, ventral tegmental area, anterior cingulate cortex, and a partridge in a pear tree (just kidding about that last one). Seriously though, with that much brain real estate involved in fat smell and taste perception, it must have been very important for our species to pick up on those sensations. It also might explain why it is so difficult to resist fatty foods. In fact, when we eat fatty foods, reward pathways in the brain are activated which makes eating that burger and French fries all the more enjoyable.
What about other animals – after all this is a comparative blog?
Okay, I’ll admit I wrote this one after giving in to a cheeseburger craving. Interestingly, the review also mentioned studies that identified certain proteins that were thought to be responsible for detecting fatty tastes and smells in Drosophila melanogaster as well – and I only thought they were after my wine…
Jaime-Lara RB, Brooks BE, Vizioli C, Chiles M, Nawal N, Ortiz-Figueroa RSE, Livinski AA, Agarwal K, Colina-Prisco C, Iannarino N, Hilmi A, Tejeda HA, Joseph PV. A systematic review of the biological mediators of fat-taste and smell. Physiological Reviews. In press. https://doi.org/10.1152/physrev.00061.2021