The book discusses this a bit, actually. It basically credits the UPF theory to one Brazilian researcher, Carlos Monteiro, and discusses how he developed the theory by applying epidemiological techniques to the obesity epidemic in Brazil. It gives the specific example that, in Monteiro's research, if a family bought sugar at the grocery store, it actually reduced the likelihood that they were obese because, even though sugar is not healthy, it meant they were still cooking at home.
My understanding is that he would probably make similar predictions about your examples: people who eat fried chicken and chocolate as part of a mostly home-cooked diet are less likely to be obese than people who drink diet coke as part of a diet that mostly comes out of wrappers. He would probably also say that there's nothing inherently bad about diet coke, but there is something bad about getting all your food from people trying to make money instead of from people who love you.
I thought that aside from the social context above, there is a theory that artificial sweeteners actually cause paradoxical effects in the metabolism because of triggers associated with the sweetness not the glucose/sucrose content. Ie specifically "diet" soda aside from eating out a Lot, may not be helping.
I'd say "calorie dense food that's highly palatable makes it easy to consume more calories than you expend, and that makes you fat". -- I mean, that's a mechanical model explaining how you get fat.
I think that UPF mostly aligns with that in that the food that's "UPF" is generally calorie dense, highly palatable, low satiation.
But...
> He would probably also say that there's nothing inherently bad about diet coke, but there is something bad about getting all your food from people trying to make money instead of from people who love you.
At this point, it seems more a discussion of morals and social values rather than a scientific "how to lose fat".
My understanding is that he would probably make similar predictions about your examples: people who eat fried chicken and chocolate as part of a mostly home-cooked diet are less likely to be obese than people who drink diet coke as part of a diet that mostly comes out of wrappers. He would probably also say that there's nothing inherently bad about diet coke, but there is something bad about getting all your food from people trying to make money instead of from people who love you.
e.g. obviously not practical for everyone but Taub's "Twinkie Study" showed fat 27 lbs of fat loss even from a diet of decidedly calorie-dense food like twinkies and doritos. https://www.psychologytoday.com/us/blog/comfort-cravings/201...
I think that UPF mostly aligns with that in that the food that's "UPF" is generally calorie dense, highly palatable, low satiation.
But...
> He would probably also say that there's nothing inherently bad about diet coke, but there is something bad about getting all your food from people trying to make money instead of from people who love you.
At this point, it seems more a discussion of morals and social values rather than a scientific "how to lose fat".