The 'industrial' in the title is doing real work. Small amounts of trans fats occur naturally in dairy and in meat from cattle and sheep. The ones public health people go after are the partially hydrogenated oils that used to be in everything from margarine to packaged biscuits.

I didn't know there were natural ones. Is there evidence they're less harmful, or are they just harder to regulate away?

I'd want a nutritionist to answer that properly rather than me. My understanding is that the evidence is less clear-cut, and the amounts in a normal diet are small. The industrial ones were in much larger amounts, in much more food.

Labelling rules are the sneaky part in a lot of places. In the US, a serving with under half a gram can be labelled as zero, so a product can say '0 g trans fat' and still contain some. A smaller serving size on the label helps it get under the line.

Nice to see this covered at all. Food policy outside the US and Europe rarely makes it into what I read, and it's often where the more interesting experiments are happening.