The main finding of the present study was that, in contrast to our hypothesis, eucaloric, isonitrogenous high‐protein vegan (VEG) or omnivorous (OMNI) diets improve peripheral insulin sensitivity (IS) in people with T2D to a similar degree, despite an additional 22 g fibre per day from the mycoprotein‐based products in VEG. This evidence concerns the gene INS and type 2 diabetes mellitus.