Fully hydrogenated fats contain (virtually?) no trans fats. I'm curious why the shift was to palm oil, rather than to just fully hydrogenating the oil and then blending it with unhydrogenated oil to achieve the desired consistency.
This is true: oils that have undergone full hydrogenation become saturated fats, because the carbon double bonds break and bond and with excess hydrogen until the fatty acid is fully saturated. The cis/trans distinction affects the double bonds, which no longer exist once the molecule is saturated.
On the other hand, advocacy about the likely adverse health effects of saturated fats has been commonplace for a lot longer than the awareness of trans fats. This, together with likely consumer confusion about terms like "partially hydrogenated" vs. [fully] "hydrogenated", and the unwieldiness of using a solid-at-room-temp fat in a blend all add up to reasons why it's probably easier to use palm oil.
So far, coconut oil and palm oil have largely managed to avoid being caught up in the conversation about saturated fats. Marketing and market positioning undoubtedly plays a key role. The other is nutrition as a field of study and a topic of conversation: rigor is hard to achieve, conflict of interest is everywhere, advice is a mix of unhelpful and conflicting, and pop publications do even more disservice by repeating soundbites without caveats and context. In a few years, the next 'awakening' -- helped by the awful environmental and social justice of tropical oils -- will probably purge coconut oil and palm oil from manufactured foods in some countries, and we'll migrate to some other inconvenient tradeoff whose true consequences will become widely known only much much later, all the while the public is pleased that they precipitated positive change.
