The history of nutritional advice studies is extremely noisy and full of questionable, later reversed discoveries that have been p-hacked into existence. I think people are right to be very, very wary of rejecting the null hypothesis about anything without extremely solid clear evidence.
I don't disagree at all, but is there anything ambiguous about the health benefits of avoiding UPFs as defined by the Nova classification system? It seems the criticism I was responding to was more about the classification system being too strict, rather than lacking clear evidence of health benefits.
Nova does not make any judgment on the healthiness of foods, to my knowledge. The problem is that people take the extremely broad classification of UPFs by Nova, infer health detriments, and then cast judgment on the overly broad UPF classification as if everything in that category is equally as bad.
Here's a reminder of the Nova UPF classification:
> Industrially manufactured food products made up of several ingredients (formulations) including sugar, oils, fats and salt (generally in combination and in higher amounts than in processed foods) and food substances of no or rare culinary use (such as high-fructose corn syrup, hydrogenated oils, modified starches and protein isolates). Group 1 foods are absent or represent a small proportion of the ingredients in the formulation. Processes enabling the manufacture of ultra-processed foods include industrial techniques such as extrusion, moulding and pre-frying; application of additives including those whose function is to make the final product palatable or hyperpalatable such as flavours, colourants, non-sugar sweeteners and emulsifiers; and sophisticated packaging, usually with synthetic materials. Processes and ingredients here are designed to create highly profitable (low-cost ingredients, long shelf-life, emphatic branding), convenient (ready-to-(h)eat or to drink), tasteful alternatives to all other Nova food groups and to freshly prepared dishes and meals. Ultra-processed foods are operationally distinguishable from processed foods by the presence of food substances of no culinary use (varieties of sugars such as fructose, high-fructose corn syrup, 'fruit juice concentrates', invert sugar, maltodextrin, dextrose and lactose; modified starches; modified oils such as hydrogenated or interesterified oils; and protein sources such as hydrolysed proteins, soya protein isolate, gluten, casein, whey protein and 'mechanically separated meat') or of additives with cosmetic functions (flavours, flavour enhancers, colours, emulsifiers, emulsifying salts, sweeteners, thickeners and anti-foaming, bulking, carbonating, foaming, gelling and glazing agents) in their list of ingredients.
A few items that stick out like a sore thumb to me regarding healthiness:
* How could sophisicated packaging, usually with synthetic materials impact health?
* How does making something highly profitably necessarily impact health?
* Nova's definition of something with 'no culinary use' is extremely biased in my view. How do specific sugars (each with specific properties that are useful) have no culinary use? How are protein mixes not culinarily useful?
* Nova's definition of 'cosmetic function' is also just.. stupid in my view. Flavors are cosmetic? Emulsifiers are cosmetic? By this definition, adding MSG to a food makes it UPF.
While I can't speak to all of your questions / criticisms, food packaging is responsible for releasing a wide range of chemicals that are either known or suspected to be harmful to some (men, pregnant women, etc) or all humans, including BPA, phthalates, xenoestrogens, per- and poly-fluorinated substances, and microplastics. I'm sure there are many others, those are just the ones that come to top of mind for me.