So I don't think anybody knows why they're bad. Surely the UPF classification includes lots of foods that are harmless. We just don't know which ones because we don't understand the mechanism.
We have this (reasonably) rigid definition that grants the appearance of specificity. But there are almost surely UPFs that are fine and there are probably non-UPFs that cause the same problems as UPFs. Potato chips are hyper palatable, but are not UPFs.
So what is the benefit of saying "avoid UPFs" over "avoid junk food?" At least saying "avoid junk food" makes the fuzziness apparent. But by focusing on this UPF definition (which is almost surely not the actual thing that is causing negative health outcomes) we end up in weird scenarios where potato chips and bean-to-bar chocolate are fine but wheat bread with preservatives are not even if it turns out that the preservatives aren't the source of any problem.
Not "almost" or "probably"; both are certain: Any description of reality fails on those standards. Always, there are exceptions and edge cases: 'We have this (reasonably) rigid definition that grants the appearance of specificity. But there are almost surely X that are fine and there are probably non-X that cause the same problems as X.'
To meet your standards, we would need a list of every food and its status - and that couldn't be created without impossibly extensive research.
That's why humans use imperfect models and categories - reality is too complex. The most specific, usable category seems to be 'ultra-processed foods'.
> So what is the benefit of saying "avoid UPFs" over "avoid junk food?"
Good question. Both categorizations will be flawed, but maybe UPF is a better fit or easier for people to understand.
It is the case that several of the prominent voices against UPFs have said some ridiculous things in this direction. Like that a packaged lasagna that is made entirely from ingredients and processes that a home cook would use to make lasagna is bad because it comes from the same corporations and market forces that also produce the frozen lasagnas that are loaded with stabilizers and added sugar.
Potato-chip bags are probably the most sophisticated packaging used for any food you see routinely.
That does not, of course, mean that they are bad for you.
I, and other people argue that it has nothing to do with the processing and it’s all about the ingredients. So the whole differentiation by “processing” amount is useless. We are talking about ingredients without wanting to say so.
P.S. That being said, I still hate the term ultra-processed. "Junk food" implies the non-specificity better. https://news.ycombinator.com/item?id=45979589
Likewise the categorization of processing is useful for exactly the same reason the category of poisoned is useful. I'd rather not consume poisoned food of any variety even if I'm uncertain which poison has been added to it.
Yes, the UPF classification used here likely flags some false positives and perhaps misses others, but if the methodology is otherwise sound and the link is there, even if fuzzy, I don't think it's as easy as you claim either. And even if if fuzzy, it's still useful as I would be healthier avoiding UPF (assuming accurate study), even if I would also avoid some perfectly healthy foods.
Linnaeus did this, and allowed himself to be wrong, and I argue his organization alone was necessary to talk about theory.
They certainly meet the ultra processed foods criterion.
Nitrates in meat cause stomach cancer (another thing we can't undo by legislative fiat) but probably don't cause the global pandemic of metabolic disease.
And, since I know it's inevitably coming, 'humans have been eating meat forever!' - no they absolutely have not:
1. Processed meats are a new thing. There is a difference between eating a cow, and taking cow meat and chemically changing it forever.
2. Farmed meat is a new thing. Prehistoric humans ate meat that is nothing like the meat we eat.
3. Eating meat is a new thing. For almost all of human history, until maybe ~50 years ago, humans ate very little meat. Even today, only the West eats high amounts of meat. We also only see metabolic syndrome in obesity in the West/the developed world. Do with that information what you will.
> Metabolic syndrome is a clustering of at least three of the following five medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein (HDL).
The pandemic of obesity and metabolic syndrome started about 50 years ago, and is not limited to "the West" or "the developed world". Mass consumption of meats processed with nitrites (producing nitrates as a byproduct) goes back at least several centuries, maybe a millennium.
"Farmed meat", if by that you mean factory-farmed meat, is facially plausible as a cause, in that it fits the timeframe. However, people with metabolic syndrome who switch to an all-meat diet, even if the meat is factory-farmed, tend to improve rather than worsening.
> Mass consumption of meats processed with nitrites (producing nitrates as a byproduct) goes back at least several centuries, maybe a millennium.
Incorrect, at least in what you mean by 'mass'. We eat significantly more meat now than 50 years ago.
> However, people with metabolic syndrome who switch to an all-meat diet, even if the meat is factory-farmed, tend to improve rather than worsening.
There's a few huge, glaring problems here:
1. You made this up, this isn't actually the conclusion of any study anywhere.
2. Any restrictive diet, yes ANY, can and will cause you to lose weight and therefore work against 'metabolic syndrome' (which, again, is not a disease, it's a syndrome). Yes, eating less calories WILL cause you to lose weight. You can achieve the same thing by eating only sugar, or only bread, or only cheese.
3. We know, for a fact, that diets with high meat consumption are correlated with obesity, heart disease, etc. We know diets LOW in meat consumption, particularly red meat or meat high in saturated fats, are correlated with lower CVD risk and longer longevity. Do with that what you will.
And, if you still don't buy many decades of studies on this, you can also just use your intuition.
Look around the world at where we see obesity and where we don't. We see it in the UK, Canada, the US. We don't see it in Japan, parts of Asia, and the Mediterranean. What's the difference?
Those places have a culture of eating significantly less meat, especially red meat. They also have a culture of eating smaller portions. Many of them have a culture of walking. Many of them still eat processed foods.
And, none of this even touches on the carcinogenic factors of red meat. We know, for sure, red meat is carcinogenic - it's classified the same as alcohol and tobacco.
Really what's going on is people are trading off stuff they think might be bad for stuff we know is bad.
There's a lot of people who won't drink a diet coke because it's 'poison' but will happily eat bacon. When we know bacon causes cancer, but we don't know if aspartame does, despite us studying it to death.
It's a form of self destruction. People think to be healthy you must deprive yourself, you must suffer. It's just not true.