A new study conducted by the University of California, Berkeley, US, has found that the smell of food could lead to weight gain and vice-versa.

The finding is based on the results of experiments that saw the connection between temporary elimination of olfactory, smell system, neurones in the noses of adult mice, and weight loss.

UC Berkeley researchers used gene therapy to temporarily destroy olfactory neurones in a set of mice, sparing stem cells, for three weeks.

The study observed that the smell-deficient mouse remained a normal weight while eating a high-fat diet compared to the mouse with a sense of smell, which gained weight on the same high-fat diet.

Los Angeles Cedars-Sinai Medical Center former UC Berkeley postdoctoral fellow Céline Riera said: “This paper is one of the first studies that really shows if we manipulate olfactory inputs we can actually alter how the brain perceives energy balance, and how the brain regulates energy balance.”

"Weight gain isn’t purely a measure of the calories taken in; it’s also related to how those calories are perceived."

The researchers also found that already obese mice lost weight after their smell was lost while still eating a high-fat diet. It was also observed that these mice lost only fat weight, with no effect on muscle, organ or bone mass.

UC Berkeley researchers also partnered with colleagues in Germany and discovered that mice with more acute olfactory nerves gained more weight on a standard diet than normal mice.

Molecular and cell biology professor Andrew Dillin said: “Sensory systems play a role in metabolism. Weight gain isn’t purely a measure of the calories taken in; it’s also related to how those calories are perceived.

“If we can validate this in humans, perhaps we can actually make a drug that doesn’t interfere with smell but still blocks that metabolic circuitry. That would be amazing.”

The research received support from the Howard Hughes Medical Institute, the Glenn Center for Research on Aging and the American Diabetes Association.

Image: A burger. Photo: courtesy of Robert Owen-Wahl via FreeImages.com.