I have stated elsewhere on the forum that I think that unsaturated fats may act as environmental signals which convey specific information to the organism. Namely, that hibernation/a low energy state is approaching. We see this in many species, both plant and animal. The unsaturation of their tissues changes depending on which time of year it is. Hibernation in animals, and TOPOR in plants relies on unsaturated fatty acids, and seems to be the signal for animals to:
1. become insulin resistant (to gain adipose fat to sustain winter hibernation)
2. inhibit thyroid function to lower the metabolism (high metabolism would lead to starvation for an animal with no food)
It would also make sense that ketosis should be coupled with winter, unsaturation, cold temperatures, and low metabolically stressful conditions. In other words a low energy state. It is well known that ketosis produces less free radicals. Free radicals are a major problem with PUFAs in the body, so it makes sense that less should be produced. For more information on this topic, this blog is helpful:
PUFA in evolutionary and environmental context
Perhaps there is a physiological role for PUFAs in humans living in traditional winter conditions, but that has changed now IMO.
My feelings on this are that
we are not living in our traditional environment. Anyone can argue for eating the way that our ancestors evolved to eat, but to me this seems futile. We live in chronically stressful environments, with artificial light 24/7, and insane amounts of environmental toxicity. We are bombarded every single day. Therefore, a different strategy is called for IMO. I tend toward thinking that providing a constant supply of simpler, more readily accessible fuel is the safest way to approach the situation. Controversial yeah, but that's where I'm at at the moment.