Can you please expand on that? Because if I remember correctly, at least in Eastern Europe jam is made by boiling fruits with sugar, simmered down until it thickens. What boxes is exactly homemade jam ticking?

Indeed. If you don't add the sugar, its group 1: minimally processed. If you add industrially made sugar (a group 2 item), it becomes group 3: processed.

This commercial jam[0] is made with exactly the same ingredients as would be used to make home-made jam. It is Nova Group 4.

The problem with the group 4 definition is it is a mix of things that are genuinely harmful, things that are completely irrelevant to the health of a given food item, and broad, vague definitions that could be used to describe almost any prepared food item as “ultra-processed” if one were so inclined.

0 - https://world.openfoodfacts.org/product/0096619217939/organi...

I make jam at home. I usually just heat the fruit (strawberries, raspberries etc) alone, with not even added sugar. That's group 1. If I add sugar, it becomes group 3. If I did add pectin for some reason, it becomes group 4.

Yes, I agree that group 4 is very broad, but I think as an initial attempt its good. Breaking things down into further groups is going to confuse people a lot more, especially because there are no distinct categories here. Too much overlap. Just asking people to eat less of group 4 is a much more reasonable public health objective.

> I make jam at home. I usually just heat the fruit (strawberries, raspberries etc) alone, with not even added sugar.

You'll never guess what is extracted from the fruit when you do this.

But nobody uses industrial chemicals and processes at home. That said, I would consider refined sugar as ultraprocessed, and homemade jam includes a lot of it.

Refined sugar is Group 2: Processed culinary ingredients [1], not group 4: ultraprocessed. It's preparation does not include any of the steps specified in my quote above.

[1] https://world.openfoodfacts.org/product/8850256100106/mitrph...

Sure, but the natural next step after ultraprocessed is highly refined products like sugar and flour, which I know is so much of people's current diet but that's why everyone has health problems.

NOVA considers most homemade jams ultra-processed not because of sugar, which is widely understood and proven to be unhealthy, but because of the use of fruit pectin as a gelling agent.

The irony here is that the more processed pectins can be used to reduce the amount of sugar in homemade jams (while still maintaining a jam-like consistency.)