It might be an oversimplification, but one of the paleo mantras counter to conventional wisdom is: "you are not what you eat." You don't become fat from eating fat; you become fat from eating carbs.
But fat isn't all bad. Much of the brain is made of fats. Myelin is 70% fat. Those kinds of fats do originate in dietary fats. ALA and LA turn into DHA and AA. You need both Omega-3 and Omega-6 in your diet.
But are there any essential fats that depend on dietary carbohydrates?
Suppose you're a pregnant mother under the PaNu influence. And you're getting plenty of good fats.
Are there any tissues that a baby can only build from carbohydrates in the mother's diet? Is ketosis during pregnancy dangerous?
There's lots of talk out there, but I'd like to hear some science.