Want the benefits of exercise without lifting a finger? There might be a pill for that

Scientists have discovered a molecule produced during exercise that suppresses food intake and enables weight loss in mice, which they hope could be used as a human therapeutic in the future. 

A collaboration of researchers, from institutions that include Baylor College of Medicine (TX, USA) and Stanford School of Medicine (CA, USA), set out to uncover the effects of exercise at a molecular level, hoping to find benefits that could inform preventative medicine in the future. They achieved their goal, discovering a molecule that mice produce when exercising that reduces the animal’s food intake and obesity levels.  

“Regular exercise has been proven to help weight loss, regulate appetite and improve the metabolic profile, especially for people who are overweight and obese,” explained co-corresponding author Yong Xu (Baylor). “If we can understand the mechanism by which exercise triggers these benefits, then we are closer to helping many people improve their health.” 

Through analysis of blood plasma taken from mice following intense treadmill exercise, they found that a modified amino acid – named Lac-Phe – was the most significantly induced molecule. Lac-Phe is produced from a reaction between a by-product of exercise, lactate, and the amino acid phenylalanine. 

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When mice with obesity – which was induced through a high fat diet – were administered Lac-Phe, their food intake reduced by around 50% over a 12-hour period, when compared with a control group of mice. When this was extended over the space of 10 days, the mice continued to eat less, and lost body fat, and therefore body weight, as a result.  

Interestingly, the team also discovered that the lack of an enzyme involved in the synthesis of Lac-Phe – CNDP2 – meant that these mice didn’t lose as much weight on a specific exercise plan as a control group of mice on the same exercise plan did. 

Following these promising results, the team looked at Lac-Phe levels in racehorses and humans, discovering that there were marked increases in both during exercise, with sprints, resistance training and endurance training showing the biggest increases in humans. 

“Our next steps include finding more details about how Lac-Phe mediates its effects in the body, including the brain,” concluded Xu. “Our goal is to learn to modulate this exercise pathway for therapeutic interventions.”