The secret to man's intelligence? POTATOES enabled larger brains

Wow, this is sloppy journalism. Ar drallison points out, potatoes (any subspecies) were unknown to the Old World altogether. The article makes multiple references specific to potatoes ("It has been argued that an increase in meat consumption could have triggered the increase in size, but now scientists believe that we may have another food to thank: the humble potato.", and "They say starches would have been readily available to ancestral human populations in the form of potatoes", which is categorically false

The article implies that dietary glucose is necessary for survival, let alone optimal brain development. Neither is true, as anybody who has eaten a ketogenic diet (like me) can affirm. Although some organs need glucose (the brain is not one of them!), the body can make all it needs from protein.

Agriculture only goes back 15,000 years or so, which is a blip in evolutionary terms. There is no indication of timeframe of the amylase adaptations,

The study is here: http://www.jstor.org/stable/10.1086/682587

The abstract makes some similar claims about the need for dietary carbohydrate, citing a 27-year-old paper, which is simply incorrect.

The starchy carbohydrates were probably not potatoes which are a new world plant and domesticated fairly recently. https://en.wikipedia.org/wiki/Potato.

The article states: "Dr Karen Hardy and her team at the Autonomous University of Barcelona say that there are five crucial reasons why a starch-rich diet was critical in human development." That suggests that the key is "a starch rich diet" rather than potatoes that enabled larger brains. It would be interesting to know where the starches came from, given that potatoes are not an option.

Full subtitle: "POTATOES: Humans evolved large brains because our ancestors ate starchy carbohydrates"

Our saliva suggests improved carbohydrate digestion: "...humans possess six salivary amylase genes, while other primates just have two, increasing the ability to digest starch. ...after cooking became widespread and the salivary amylase genes multiplied, this increased the availability of dietary glucose to the brain and foetus which, in turn, allowed the acceleration in brain size which occurred from around 800,000 years ago onwards."