TLDR - Linoleic acid is bad, has gone up by 140%, has a half life of 600 days, and gets stored in fat tissue, Dietary sources of LA (industrial oils) have a direct influence on body composition.
Linoleic acid (LA) is a bioactive fatty acid with diverse effects on human physiology and pathophysiology. LA is a major dietary fatty acid, and also one of the most abundant fatty acids in adipose tissue, where its concentration reflects dietary intake. Over the last half century in the United States, dietary LA intake has greatly increased as dietary fat sources have shifted toward polyunsaturated seed oils such as soybean oil. We have conducted a systematic literature review of studies reporting the concentration of LA in subcutaneous adipose tissue of US cohorts. Our results indicate that adipose tissue LA has increased by 136% over the last half century and that this increase is highly correlated with an increase in dietary LA intake over the same period of time.
Full Paper https://doi.org/10.3945/an.115.009944
TLDR for the TLDR - Industrial Oils are bad, don't eat them.
This is relevant to carnivore because industrial oils are made from plant seeds, and carnivores avoid plant products. Even people following a strict ketogenic diet still get plenty of industrial oils in their food. Even whole food, single ingredient, diets still recommend industrial oils. It's everywhere.