It helps that we’re right. That it can’t be bad to eat what humans have eaten for 2 million years.
But 2 recent things I’ve looked at were studies done a few decades ago and shelved because they didn’t get the “right” answer, but were recovered recently and published showing the lipid hypothesis was wrong and the cause of metabolic disorder was carbohydrates
They were suppressed in the 70s and 80s, now they are published. Dietary guidelines in Australia (one of the biggest wheat exporters) now allow low carb for treating type 2 diabetes.
I do believe we’re watching a change in consensus (which as always is progressing one death at a time - perhaps it’s good that the other side is committed to a metabolically dangerous path)
You need to live to ~20, call it 45 to raise several children (you need probably 3 surviving ones per couple in an ice age) and the only food option is the animals that can eat the plants below the ice
You need to be able to live on meat your whole life or your line dies out when the cold comes, you need to be able to live on meat all winter in interglacials because no plants that we can eat are available