A diet that is too heavy on meat and carbohydrates like some American diets is also bad for health - without the fibre, one is at higher risk from cancer and constipation (starting with the cs :) among other issues
the correct diet is in-between: eat a lot of veggies, but also some meat, fish, eggs, etc. Even red meat is perfectly fine in moderation (depending on your genes that can be once a week or more) and fat is good, again, in moderation.
Probably the only really bad thing to avoid (with no redeeming quality) is refined sugar. Zero value.
And refined white sugar is everywhere - even down to bread etc.
Sounds like you’ve been reading The Guardian’s Food columns. Which are excellent really but down on American food in typical Guardian style. If you don’t like sugar or are afraid of it on health grounds, it is easy to avoid.
You just need to be careful in what you buy. Reading labels is a must. Whole Foods, now owned by Amazon, sells fairly decent bread from local bakeries and their 365 brand of eggs are really good - fresh, with that bright tangerine-colored yolk. Also, shopping at farmer’s markets is another great idea.
Scotland, in particular, has excellent butchers and it is still an ongoing concern. Scotch beef is a byword in excellence. I hope they survive and flourish as an industry. Having witnessed British Peta in action on the Regent Street in London, I’ve come to realize that the group is filled with seriously mentally ill young people.