Having lost a ton of weight from high fat/low carb, grain & sugar-free eating, I frequently get asked for diet advice and when I tell them cut out grains, sugar, corn and sweeteners for a month and see what happens (not even high fat/low carb eating), you should hear the reactions I get. "Oh I could never do that!", "I can't give up my cereal and bread and pasta!". .
I was once the same way and had to be dragged into low carb eating by the force of how desperate I was from being so overweight. I've been amazed at how easy it is and how great I feel from eating this way and then losing weight too.
I know quite a few people with gut-related issues (GERD, colitis, frequent stomach illnesses) and they still won't listen and believe me. It's turned around many of my own health conditions.
It's depressing what a choke-hold SAD has on our society. I agree, not every way of eating is perfect for everyone, but can't some at least try grain-free for a bit and see if it helps? Thankfully, we can go out and research more of this nowadays, but still when the evidence is right in your face, folks can't let go of these foods.
Sooner or later you'll learn you can't save people from themselves. This applies to all areas of life, IMO.
Works for me, a good workout and keeps angry vegans at bay.
I'm mostly at the point where I don't even try to convince people. I can be excited about how I am doing and feeling, and if I'm vague about how I've gotten as far as I have, it's no problem. Then I don't have to hear "I could NEVER give up ...." and I just keep going.