I've seen many articles about how taste buds regrow every 10 days to 2 weeks. This is one of them
https://inshorts.com/en/news/taste-buds-are-replaced-every-ten-days-1485859902972
So for a person eating for their health sake, I mean that is what food is for, your health. If they start to eat more healthy, they will be enjoying their food as much as those people who are solely eating for taste and not for health.
I can attest to that as well from personal experience. My husband too. It wasn't easy but it's well worth it to us to make that transition. And for us it took a few weeks and a lot of experimentation on new recipes. We could then finally taste the food instead of the fat, sugar, salt and enjoyed and continue to enjoy the taste of the food.
Fruits are very sweet, tomatoes have some acid some sweet, mashed potatoes don't need added fat to be very satisfying, corn on the cob w/o added fat, our bread is whole wheat and sprouted grain w/o fat or salt added and sweet from the sprouted grain. I could go on but won't. Give it a try, you might be surprised.