There doesn't need to be one formal globally recognised definition if you understand the intent of the meaning of the word.
Ketchup, protein powder, infant formula, plant-based meat and banana bread are all considered highly processed. Banana Bread less so if you decided to make it at home using raw ingredients.
The gray area is the problem. There's tons and tons of food that is likely healthy, but would meet the "ultra-processed" definition due to including certain ingredients. If those get lumped into the pile, then what is the study actually even measuring? Nothing useful in my view. If you want to make a case that a specific ingredient is harmful by itself (e.g., preservative X added to a food, all else equal, is bad) then I think that's a much stronger argument.
Right now all these studies seem to use broad strokes on the definition of ultra processed that make me think that it would be impossible to accurately remove confounding variables from the study.
Hormonal contraceptives are widely used and considered safe, but my experience with them by way of many women in my life over the years is that they really mess with the emotional composition and in some cases psychological stability of women.
It seems, anecdotally, that it isn’t all women or maybe not even most women, but many women are adversely affected, and it is difficult to know what impact second hand hormones (from many environmental sources) may be having on the children developing in the synthetic hormone soup hat has become the environment in many industrialised economies.
Birth control pills may be an essential component of an economy that has devalued labor to the point of needing two wage slaves to support a family, but I’m not sure that the increase in wealth concentration efficiency justifies the social costs.
The xeno-estrogen Ethinylestradiol is used in birth control pills because it is more resistant to degradation by the liver than bio-identical hormones.
Birth control use one of a variety of Progestins, instead of bio-identical Progesterone USP, for the same reason.
even if another tattoo artist does it, it will still be unique. hell, if the same artist does the same tattoo multiple times, each will be unique. it's not even remotely the same as seeing an image in Google image search, and using it for whatever without permission.
This is anathema to the whole industry though. You can't do this and also remain a tattoo artist in good standing with the rest of tattoo-dum. It's akin to a punk band calling the cops on someone in the crowd for singing along.
If I buy a pound of sugar, doesn't it matter how long it takes me to use that sugar in order to have any relevant insights? If I buy a pound of sugar a week, that's a really different implication than buying a pound of sugar only once per year.
Is it ketchup? Is it protein powder? Is it infant formula? Is it plant-based meat? Is it banana bread?
Is it based on the number of ingredients? Is it based on a preparation method?
This is the core problem with just about every article or study on UPFs