Repreive
Tourist
Why the heck would I need a 'scientific study' to show that which anybody whom has ever gone to the store can see?This is pretty much the only true thing in your post. You've made a bunch of wild claims about veganism. Fine. Prove them. Give me verifiable scientific studies that back up your claim that the average person cannot sustain veganism without tremendous cost to themself.
Animal-based products provide greater nutrient density and quality than vegetable matter, this much is something nobody can disagree with.
Animal-based products receive subsidies in most developed nations due to the above.
And surely you are aware that there's more than one kind of 'protein'?
The labels on food products don't define what kinds of proteins there are in a food nor their quality, only telling you how much there is by quantity.
You don't need a study to know this. You just need a moment to consider the fact and realize it's true.
Processed foods are often composed of very basic proteins and other nutrients...
You can find a single plant providing the ingredients for more heavily processed foods of all sorts, from pies and nuggets to pasta and pizza.
These ingredients are essentially pre-digested by virtue of just how much they've been separated, melted down, 'refined' and slopped about.
The problem with many alternatives to animal-based products is they tend to be more processed in nature...
And for those plant-based foods which aren't, they typically include so much fiber that the bio-availability of all present nutrients drop. Worse, the more fiber you intake, the less efficient your body becomes in absorption thereof such that it can easily leave you bloated and paradoxically malnourished.
If you don't believe this, search for it yourself... It's not terribly difficult to find the results. It's a fairly well-known issue with fiber-heavy diets.
The Role of Dietary Fiber in the Bioaccessibility and Bioavailability of Fruit and Vegetable Antioxidants
Antioxidants are abundant compounds primarily found in fresh fruits and vegetables, and evidence for their role in the prevention of degenerative diseases is continuously emerging. However, the bioaccessibility and bioavailability of each compound differs ...
www.ncbi.nlm.nih.gov
Soluble Dietary Fiber, One of the Most Important Nutrients for the Gut Microbiota
Dietary fiber is a widely recognized nutrient for human health. Previous studies proved that dietary fiber has significant implications for gastrointestinal health by regulating the gut microbiota. Moreover, mechanistic research showed that the physiological ...
www.ncbi.nlm.nih.gov
Dietary Fiber and Availability of Nutrients: A Case Study on Yoghurt as a Food Model
Open access peer-reviewed chapter
www.intechopen.com
Anyhow... As for the more processed foods, the body seems to have issues with them simply because they're so heavily processed, typically resulting in obesity alongside nutrient deficiencies.
And finally, a personal note... Some people simply cannot survive on a vegan diet as they can't break down alternative sources of protein or iron properly. My own family can neither afford a vegan diet nor survive on it due to the above issue as regards iron.