If you thought the willpower you harnessed to skip out on freshly baked cookies or the pizza your friends ordered was helping you lose weight, you might want to rethink that. It turns out even smelling those calorie- and carb-rich foods could be messing with your waistline.
According to a new UC Berkeley study published this week in Cell Metabolism, your sense of smell is linked to weight gain, possibly because the smell determines whether your body stores fat or burns it off.
"Sensory systems play a role in metabolism," said senior study author Andrew Dillin, the Thomas and Stacey Siebel Distinguished Chair in Stem Cell Research and professor of molecular and cell biology. "Weight gain isn't purely a measure of the calories taken in; it's also related to how those calories are perceived."
Researchers put mice into three groups — "super-smellers" that have a boosted sense of smell, those with a temporarily disabled sense of smell and a control group — and had them eat the same, high-fat "Burger King diet."
The mice with the superior sense of smell gained the most weight, doubling in size, while those who couldn't smell gained a maximum of 10 percent of their body weight. The control group gained less than the super-smellers, but more than the non-smellers.
This study points to a key connection between olfaction — our sense of smell — and to not only to appetite, but also to metabolism. Food you can't smell likely gets burned instead of being stored as fat, while food that stimulates your nasal senses likely gets stored, hence the added weight gain. In other words, those who can't really smell the beefy, cheese goodness of a Taco Bell Chalupa, are probably metabolizing it significantly better.
But that doesn't mean you should go plugging up your nose to lose weight. Researchers pointed out that it's common for people who've lost their smell sense due to old age, diseases like Parkinson's or injuries to become depressed and stop eating.
Instead, using these new findings, science may be able to find a way to help "super-smellers" as well as those who have lost their sense of smell properly stabilize their metabolism. "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," Dillin said. "For that small group of people, you could wipe out their smell for maybe six months and then let the olfactory neurons grow back after they've got their metabolic program rewired."
What Do YOU Think?
Does it surprise you that your sense of smell could be so closely related to how your body metabolizes food? Will this study change the way you smell and eat? Do you think this study will be significant in the way obesity and eating disorders are treated?