When mammals, including humans, are exposed to cold temperatures, they burn calories to keep warm. That, in turn, makes us hungry. Researchers have identified the brain circuits that increase appetite when mice get cold.
Neuroscientists at Scripps Research found a cluster of neurons in mice brains that act as a hunger switch during cold weather. Knowing where this “switch” is in animals may lead to weight loss treatments for people.
Because being cold leads to a higher metabolism, “cold therapies” like ice baths have been used by some people for weight loss and metabolic health for years. But the changes in our metabolism aren’t biologically meant to make us lose weight; they’re meant to keep us warm. That’s why we get hungry.
Researchers found that they could manipulate the switch. They could make the mice feel hungry when they were warm. They could also block the neurons in the mice’s brains while cold, but their bodies still had higher metabolisms — working harder to keep them warm. By separating hunger from metabolism, they made the mice burn calories without feeling deprived.
If this research can be translated into human tests, it could be a huge breakthrough in weight management therapies.
“One of our key goals now is to figure out how to decouple the appetite increase from the energy-expenditure increase,” said study senior author Dr. Li Ye. “We also want to find out if this cold-induced appetite-increase mechanism is part of a broader mechanism the body uses to compensate for extra energy expenditure, for example after exercise.”
In other words, the work could lead to medications that separate metabolism from hunger. That could mean drugs that make a person not feel hungry after exercising. Being able to burn calories and not feel the need to replace them could help people who are trying to lose weight do it without feeling deprived and hungry. It could make goals more easily achieved and make workout routines or diets easier to stick to.
This work is ongoing, but it is exciting. We always stress that it’s important to remember that animal studies aren’t the same as human trials, but this could lead to a massive breakthrough. We usually cover tips and techniques you can apply to your daily life. But we also like to bring you news stories about important research that might be shaping the future of medicine.