Nick NorwitzMD PhD, Oxford-Harvard | Metabolic Health Educator | “Stay Curious”

THIS is SO Much Better than Caloric Restriction! 💪 #microbiome #metabolichealth

16 Feb 2025 · 2 min

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1:30

In this short video, the presenter highlights a recent Nature study that fed the gut‑bacteria‑derived bile acid lithocholic acid (LCA) to mice. The experiment showed that LCA dramatically lowered blood glucose, raised GLP‑1 levels, and produced a suite of muscle‑related improvements: a higher proportion of oxidative muscle fibers, stronger grip strength, longer running distances, increased mitochondrial content, and enhanced muscle regeneration via activation of muscle stem cells. Because traditional caloric restriction (or GLP‑1 receptor agonists) can cause muscle wasting, the speaker argues that LCA may capture the metabolic and longevity benefits of caloric restriction while preserving—or even boosting—muscle health. The video concludes by suggesting that natural compounds like LCA could be incorporated into dietary approaches such as fasting or ketogenic diets to tap evolutionary health pathways without severe calorie cuts.

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What if a molecule made by your gut bacteria could unlock the benefits of caloric restriction, like improved health and longer life, but without cutting calories? New research in Nature has identified a bile acid called lithocholic acid to see what the benefits of feeding LCA to mice directly had on their physiology, and found astonishingly LCA lowered blood glucose and also increased GLP-1 levels, improved various aspects of muscle performance, including increasing the number of oxidative fibers, improving grip strength, increasing running distance, and increasing mitochondrial content in the muscles, and improving muscle regeneration and recovery by activating muscle stem cells. How cool is that? And the benefits on muscles are particularly notable because normal caloric restriction, low-calorie diets, can lead to muscle wasting. As, for that matter, can GLP-1 receptor agonists. Remember, LCA also increased GLP-1. But LCA appears to benefit muscles, meaning potentially benefits of caloric restriction without the one, the major potential downside of caloric restriction. This work highlights how we might harness natural compounds in dietary strategies like fasting or keto, to unlock evolutionary pathways for better health, but without extreme calorie cuts.