The only consistent thing about liberalism is their inconsistency. It's hard work keeping together the various sorts of anti-reality notions that underlie modern liberalism. Of course, actually presenting a cohesive worldview is unnecessary when invective suffices in responding to challenges.
Diet is one of the more subtle pillars of leftism. As with all liberal beliefs, the low-fat diet is grounded in both academic spuriousness and social support amongst adherents. We expect defense of the low-fat paradigm to rest on shoddy evidence, as almost all anti-meat studies do not control for differences in general health conscientiousness between groups. But something interesting happens when the vegetarian mafia encounters evidence undermining their religion; they sometimes commit unbelievable errors relevant to their other beliefs.
Here's Amanda Marcotte admitting to the notion that racial groups differ, i.e. HBD (seriously):
This was heavily criticized, not just by vegans but by lactose intolerant people and equality-advocacy groups that pointed out, rightly, that the assumption of lactose tolerance is casually white dominated, since European-descended people tend to digest lactose on average better than everyone else.
In other words, "equality-advocacy groups" criticize the food pyramid's implied importance of dairy, arguing that this advice only applies to white people and thus illustrates yet another incidence of anti-minority bias. Of course, Ms. Marcotte (a vegan - shocking!) also thinks that believing in racial differences (which she admits to above) is the epitome of bigotry, so once again, it's a lose/lose in her mind.
In an article from Time magazine, the anti-paleo author makes the same exact case:
For one thing, there was no single Paleolithic "lifestyle." Survival in Ice Age Europe, for instance, was vastly different from life on the African savannah, requiring different diets, behaviors and genetic adaptations.
That's the most basic premise of HBD, yet I can't imagine Time racing to hire Steve Sailer any time soon. Unless Time has embraced bioconservatism, this naked appeal to racial differences contradicts the general leftism of their magazine. For example, here's a video celebrating the Harlem's Children Zone and its founder Geoffrey Canada, a video interview with Teach for America's founder, and an article by Ta-Nehisi Coates defending Henry Gates following his 2009 arrest. I can't imagine Time champions anything except liberal creationism, so the quoted statement surely contradicts one of their central premises. Fittingly, the article attempts to maintain the credibility of anti-male and anti-white diet and exercise, whereby foreign foods and testosterone-draining workouts find favor amongst the SWPL class.
Curiously, liberals never really notice the apparent contradictions. Getting their ideas pushed matters far more than anything else.