The article says "The largest gains are obtained from consuming more whole grains, nuts and fruits and less sugar-sweetened beverages and processed meats."
I really don't think the biggest problem for someone drinking 2L of coke a day, or living mostly on ham sandwiches and hot dogs, is seed oils or oxalic acid.
Most vegetarians I know eat tons of heavily processed frankenfoods meant to mimick popular non-vegetarian foods. They also tend to eat lots of sugar and simple grains. The biggest exception has been my Indian coworkers, who tend to either make or source vegetarian meals that respect that vegetable is the root word in vegetarian.
People picking a vegetarian diet (which has been the mainstream healthy option for the last 50 years) are probably more health conscious than someone downing 5 mcdonalds per day.
French fries, donuts, and other deep fried or packaged and highly processed foods are often called “carbs” but most of the calories are from high PUFA seed oils, not carbs.
I do think high PUFA seed oils are often an issue there… they cause damage to the liver, and mitochondria, such that people feel worse, and have less energy- which in turn promotes both inactivity, and overeating. There is lots of good data on various species of lab animals getting NAFLD and metabolic diseases when swapping out MUFA and SFA for PUFA.
I should add that in watching because oxalates recently pierced my attention, and I consume lots of spinach and nuts. I'm watching this video for possible tips on mitigation, but I don't yet know the individuals who are speaking well enough to trust them as info sources.
I would definitely not trust someone pushing for the carnivore diet as a source of truth. It's very likely that, like many things, the average person doesn't have to worry about oxalates.
I wanted to point it out because it seems like that youtuber you shared is a keto influencer with an anti-vegan agenda, pushing for a carnivore diet (his words). I would not take his words as gospel.
I really don't think the biggest problem for someone drinking 2L of coke a day, or living mostly on ham sandwiches and hot dogs, is seed oils or oxalic acid.