HMM: Cutting Back on One Amino Acid Increases Lifespan of Middle-Aged Mice Up to 33%. “Isoleucine is one of three branched-chain amino acids we use to build proteins in our bodies. It is essential for our survival, but since our cells can’t produce it from scratch, we have to get it from sources like eggs, dairy, soy protein and meats. But there can always be too much of a good thing. Earlier research using data from a 2016-2017 survey of Wisconsin residents found dietary isoleucine levels were linked with metabolic health and that people with higher BMIs were generally consuming much greater quantities of the amino acid.”

Isoleucine is a popular bodybuilding supplement, and I’ve considered taking it. I think I’ll give it a pass.