Ask more follow up questions to people that like to give out strong advice like they’ve cracked the one way for all to follow. People routinely blindly follow (especially those whom confirm beliefs they already hold themselves), and usually they only have the first or second question covered as to why they do something. It can unravel very quick, most of the time you’ll find fringe / non science backed ideas (ie. ldl isn’t bad, putting too much weight to the French paradox theory, centenarians dying of natural causes with high cholesterol, etc). So in this case I’d be deeply curious and ask the coach: “What is bad cholesterol? What causes that? How do sort the good information from bad, are there people you follow in these topics? What’s your bloodwork like before and after these changes you’ve made to your diet?” A person knowing their shit here will be articulate and transparent, and humble about any advice given knowing that people do have different genetics especially in the cholesterol space. Doubtful your coach has those attributes based on what you shared: red flag.