A surprising brain signal could explain why eating less protein extends lifespan in animals, according to a new perspective from LSU’s Pennington Biomedical Research Center.

The paper, published in the journal Cell Metabolism by Dr. Chris Morrison, Dr. Sora Kim and Dr. Sangho Yu, proposes that protein restriction triggers a coordinated, whole-body response. The brain detects protein scarcity and organises changes in metabolism, energy use, growth and food choice.

A key player is FGF21, a hormone made by the liver. It acts as a signal of protein restriction, carrying the message to the brain. In animal studies, FGF21 was required for protein restriction to affect lifespan, metabolism and food preferences.

Morrison has now been awarded a $2 million NIH grant to study exactly how the brain detects dietary protein restriction. The four-year project will look at the neurons that regulate metabolism and food choice.

“How does an animal know it isn’t getting enough protein?” Morrison asked. He cautioned that more research is needed before any dietary recommendations can be made.