Waves, Chris! Yes, Dr. Gundry suggests that only low fat (white) fish, shellfish and pastured eggs are safe animal proteins for E4 carriers AND he wants us to limit these to 4 oz or less a day. As Stavia acknowledges, this is not based upon peer reviewed evidence, but rather his clinical work with hundreds of E4 patients. He's going to be speaking at our meet-up in Boulder this summer.
It's been a while since I took a deep dive into the Pima Indians, but I think the purpose of those studies was to try to find out WHY such a large proportion of this population became ill with primarily T2D and CVD when they began eating a Western diet loaded with sugar, refined carbs, and SFA. On their traditional diets (very high in carbs,) they were borderline obese, had elevated TGs, glucose, and insulin BUT low LDL. During the time this was studied, Ancel Key's lipid hypothesis was gospel. Other CVD risk factors were largely ignored. Subsequently, researchers hypothesized that it was the Pima Indian's low fat diet that guarded them from chronic illness. Looking at the raw data, this didn't lead to optimal health (far from it!) for the E4 carriers just better than when a Western diet was adopted. I always like to go back to raw data rather than trust author's conclusions as they're very often slanted by the prevailing "group think" of that era. Every traditional culture develops chronic disease once they adopt the diet and lifestyle of Westerners.
We should devote a thread to the Pima Indian studies. There are several. I'd enjoy the opportunity to carefully go through them. IMHO, they provide great examples of Westin Price's hypothesis outlined in Nutrition and Physical Degeneration.