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Comment by benrutter | Hacker News Reader

> It's just that "UPF" isn't the right metric for isolating those foods

I've heard this criticism a fair bit, and I sort of agree. The only thing is, what is the right metric? And if we don't have one, and know these foods are causing harm, should we just use UPF as a term anyway?

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There is perhaps some rough correlation but as soon as you define an objective metric then consumer packaged foods companies will figure out a way to game the metric by engineering foods to get good scores and be highly palatable while still not being very healthy. Another way of thinking about it might be ultra-formulated versus ultra-processed: what matters is the contents rather than how you got there.

https://peterattiamd.com/davidallison3/

The thing is that, although the list used (the "Nova classification") is obviously somewhat arbitrary, the fact that everybody uses it makes research results comparable to each other.

Comparable how? If I compare one meaningless number to another meaningless number on the same scale then I can see which one is larger, but I won't learn anything scientifically valuable or practically useful.

Meaningless how? A lot of significant effects were found, it can't be entirely meaningless.

Which statistically significant casual effects have been found?

It's 2 days later, but the effects found in studies are:

- Increased weight gain contain to the same calories in non-UPF - Consumption of UPF linked with obesity - Consumption of UPF linked with early death

As always, I'm sure you could argue with experimental set up, but.those are the main claims.

Source is ultra-processed people, which I mentioned earlier and someone kindly linked to.

Those are correlations found in junk observational studies, not "effects".

Correlation != causation. Your correlation can identify a hugely important effect without pinpointing its mechanism. In this case: I think it's very likely that ultraprocessing has not-very-much to do with food health, but UPF foods tend to be hyperpalatable and low-satiety, which almost certainly does. The ultraprocessing isn't what's making the foot hyperpalatable or low-satiety (the macronutrient mix and sweetening is).

The previous comment was pointing out that there's an agreed-on definition of what "ultra-processing" means. There is. But there is no such agreement on mechanistic effects of ultra-processing.

Yes, I think much of the research is trying to find out what thr cause is, and I agree itslikely to be that hyperpalatable part.

One thing I would like to see is a clear categorization of to the concept of chemically reduce ingredients into unreconizeable components, and then recombine them into the original product while presenting it as nothing has happened. If you take milk and reduce it down to fat-free milk powder, then introduce additional fat and rehydrate it with additional cream aroma, it doesn't turn back into fresh cream. Similar, if you take fruit and reduce it down into pure fructose, then reintroduce water and aroma extracted from the same kind of fruit, it may be similar but not quite like freshly squeezed fruit juice.

Canned Jalapeño often deploy a similar (but much less noticeable) trick in that the manufacturer grows Jalapeño without capsaicin, and then reintroduce chemically created capsaicin into the can in order to control for spiciness.

I don't know, it's a hard problem, but I think there's good public policy evidence that when you do these things wrong (as with Prop 65 cancer warnings and nitrates) you lose all the benefits the labeling tries to provide.

> what is the right metric?

Not sure of the formula, but it would be a metric that ignores "processing" or "unnatural" ingredients and somehow scores for high calories in absence of fiber or protein.

Examples: Apple juice: sugar calories without fiber or protein = bad

Apples: sugar calories, but has fiber = OK

Potato chips: fat and carb calories without fiber or protein = bad

Baked potato with butter: fat and carb calories, but has fiber = OK

Honestly, UPF feels like a food industry plant word to make legislation a hot mess full of holes.

Just regulate added sugar and saturated/trans fats and be done with it.

Saturated fat is not processed food and is not unhealthy. It is the most common kind of natural fat in the human diet for most people through most of history.

Different human populations had quite different diets in the past. A huge error that the paleo diet promoters make is claiming that there is a single diet shared across all humanity for most of human history.

I agree. That's why I said "most common" for "most people".

Even this is not true.

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