if you follow the "good doctor" (
https://www.youtube.com/results?search_query=pradip+jamnadas), short videos, hour plus long videos... his basic stances are pretty easy to follow, he just lays it all out...
as to why various things are "bad for us", well, i take that with a grain of salt that costs nothing

follow the money...
back in the day when "they" decided that sugar vs fat what was bad in food, they of course chose sugar (corn syrup) as the good guy, blamed fat for everything, and started pushing a food pyramid based on items that would make profits

way back in school when the food pyramid was new, we had to do a class on it, and "build" a food pyramid with real foods layed out on a table... the SUGGESTED serving portions for daily eating - huge - impossible! also, poptarts are a grain? wtf... get out.
these days, fat itself as a resource / ingredient is worth money - more so than the foods they extract it from; low fat cheese? "it's good for you" (not) but that fat is worth $$$$ for plastics and other industries, hell, even fuel industries... it might be worth more than some foods...
they really effed us over for the last 50+ years on boner moves like that. sugar IS a problem, not having the right fats IS a problem. shit, screwing with our food is the biggest crime of the century...
the only "health food" is real stuff, from nature, from animals, "eat food, mostly plants, not too much" was a good motto in the pre keto/nocarb days...
regular meals is the downfall of mankind i think. variety is good. being HUNGRY is good. even lightly processed foods lose something... OMAD does some things to you. makes your body work a little yes, but once you settle into it, you eat your food, and you're done. no snacking, no extra money spent, you're almost never hungry, hangry, tired, the body starts fixing things, no insulin spikes, things just work. it's great. one of the aspects is losing weight, a benefit, but wasn't 100% the real reason i started. fun fact: your tongue is a fat storage point too, when you lose weight, you lose that fat too, and if you have apnea? yeah! i sleep tons better now... better gut health, immune health, every box ticked.
there's a dude i follow off and on from youtube, "lion diet", he buys a half cow now and then, all cut up, bagged, frozen, and pretty much eats 2 steaks a day (love his rib eyes); his health story is amazing in his turn around, off all his meds, no more health problems that plagued him, he's in fantastic shape; i found him due to the "Dreo Chefmaster" cooking appliance i was researching then (fantastic cooking device if you crave steak)... check him out.
back to the doctor... why do people dislike him, not trust him, and people like him? because he's honest, has the science, and isn't make a penny off us (well, youtube might flip him a few dollars); but he's not selling a plan, nor supplements, nothing, in fact, he wants us health, and doesn't want our money from cutting you open (he is a working cardio thorasci surgeon, and cuts up enough people)... so yeah, that's SUS right? someone looking out for us...
bad day? have a steak. hangry? eat a steak. sad? eat a steak. tired? eat a steak