Humans Can Sniff Out Dietary Fat: Sense of Smell Impacts What We Eat

How good is your sense of smell? Apparently, it's good enough to detect dietary fat in food. Scientists have discovered that humans can sniff out fat in foods before eating it. The findings could lead to innovative methods of using odor to make low-fat foods more palatable to aid public health efforts.

It's not surprising that humans can smell dietary fat. After all, fat is the most calorically dense nutrient available and thus highly desirable when looking back over the course of human evolution. Being able to detect sources of fat in foods would be evolutionarily advantageous to people. Yet while researchers knew that humans use sensory cues to detect fact, they weren't sure exactly what sensory systems contributed to this ability.

In order to find that out, scientists decided to see whether or not people could detect and differentiate the amount of fat in milk. Volunteers smelled milk containing .125 percent fat, 1.4 percent fat or 2.7 percent fat. The participants were blindfolded when presented with these samples--two of the same fat content and one with a different fat content--and were asked to tell researchers which of the samples was different.

In the end, the scientists found that participants could use their sense to smell to discriminate different levels of fat in milk. The researchers also noted that there was no relation between weight status and the ability to discriminate fat.

"We now need to identify the odor molecules that allow people to detect and differentiate different levels of fat," said Sanne Boesveldt, one of the researchers, in a news release. "Fat molecules typically are not airborne, meaning that they are unlikely to be sensed by sniffing food samples. We will need sophisticated chemical analyses to sniff out the signal."

The findings could have implications for food products in the future. If researchers manage to parse out which odor molecules are responsible for the smell of "fat," then they could potentially create low-fat foods that are more desirable. This could help improve diets of those struggling with obesity and other health-related issues.

The findings are published in the journal PLOS One.