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‘Anti-hunger’ molecule forms after exercise, scientists discover

Two people running at sunset

Stanford researchers and their colleagues have found a molecule that suppresses appetite after intense exercise.


bunyarit klinsukhon/

By Hanae Armitage

Scientists are calling it the “anti-hunger” molecule.

New research shows that a compound induced by intense exercise travels to the brain to stifle appetite. The molecule, identified by researchers at Stanford Medicine, Baylor University and other institutions, helps demonstrate how exercise results in weight loss, and it may hold the key to kickstarting the process in people with metabolic disease.

“We’re all generally aware that exercise is beneficial. It’s good for body weight and glucose control,” said Jonathan Long, PhD, an assistant professor of pathology who led the research. “But we wanted to take a look at that concept in more detail — we wanted to see if we could dissect exercise in terms of molecules and pathways.”

The fruits of Long’s efforts, a molecule known as lac-phe, is a hybrid of two chemical compounds that naturally exist in the human body: lactate and phenylalanine. (When you've worked up a good sweat and your stomach feels like it's about the size of a pea, that's lac-phe in action.) It’s not just in people — the team also found that the molecule pops up post-exercise in mice and racehorses, suggesting the power of lac-phe may permeate the animal kingdom.

Let’s get to the question everyone wants to know: Does this finding hold promise for that ever-elusive diet pill? There’s potential — but don’t count on it just yet. The discovery does, however, open the door to new explorations of lac-phe-mimicking drugs as a treatment for metabolic diseases such as obesity. But there’s still a lot of work to be done before that could happen, Long said.