A new study says restricting our diets and sniffing our dinners might be the key to longevity.
food portions impact on lifespan
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The worst part of dieting, perhaps, is cutting portion sizes—and the constant feeling of hunger that often follows a small-but-healthy meal. Yet a new study may motivate you to endure those hunger pangs: it reveals that restricting what you eat—without starving yourself—can significantly extend the lifespan of more than 20 species in the animal kingdom. The study also showed that there's a rather odd method by which we might get those smaller portions to extend our lives: smelling our food.

Florida Atlantic University researchers studied tiny worms (C. elegans), and found autophagy—a process in which cells digest debris in our bodies—can contribute to a longer lifespan. And limiting what we eat, as well as sniffing our food, works in harmony with autophagy, they say, enhancing its benefits and influencing how long we might live.

"If you want to extend the lifespan of any animal, after limiting their diet, you have to have functional autophagy [or] you won't see this lifespan extending effect," lead researcher Kailiang Jia said in a press release. "Autophagy in the GI tract also is required for this lifespan extension mechanism, which indicates that the nutrients we absorb into the GI tract also regulate autophagy and controls the aging process."

The process is pretty complex, but here's the layman's version of the science behind it: eating less and smelling the food you do eat can trigger autophagy in the olfactory neuron, which changes the physiology of the human body on a cellular level. At least, that's the idea after studying those tiny worms, the researchers say. In other words, "autophagy in the olfactory neuron can sense the food smell," Jia explains, "and then secrete neuron signals, which in turn influence the aging process." So the takeaway is basically this: eat a little less, smell your food, and let your body extend your life.