I guess I agree on principle and diet is understated. But let's say, as has happened recently, you're looking at Alzheimer's or lewey body syndrome and you find the gwas returns a lot of results for a certain cellular pathway (like a stress response or where a cell breaks down misfolded proteins, leading to plaques). You can look for small molecule drug which targets that, or try a fancier treatment to target that exact protein. But how would that insight extend to diet?

Beyond just eating more health (in whatever way) and exercising more, which does go a long way. Thse drugs are trying to be extremely targeted and intricate in now they work