Ancestrally speaking, wouldn't Grok and Grokette find underfatted individuals unattractive and undesirable as mates?
Is today's obsession with six pack abs and sub 15-20 percent body fat comparable to the modern draw to soda and other processed 'foods?' I think so.
Just like with primal macros, people need to get over the brainwashing that coerces us to believe fat is bad.
*Obviously, I'm not talking about the obese, the skinny fat, or the bloated.