There's a great book about this called "The Diet Myth" by Tim Specter. IIRC he's a Professor of Genetics and specialized in twin studies and sort of stumbled i

There's a great book about this called "The Diet Myth" by Tim Specter. IIRC he's a Professor of Genetics and specialized in twin studies and sort of stumbled into researching gut bacteria because he was fascinated by identical twins were one was obese and other was a healthy weight. It's mindblowing how little we know and understand about such an important topic. Edit: If you're interested, this talk[1] he gave at the Boston Science Museum is what made me read his book. [1] https://www.youtube.com/watch?v=PEAdtGa549I https://www.youtube.com/watch?v=PEAdtGa549I