How the human brains got bigger?

I was reading Sapiens, and I found something very interesting.

Humans have extraordinarily large brains compared to other animals. The earliest human beings had brains off about 600 cubic centimetres. Modern sapiens have a brain averaging about 1200-1400 cubic centimetres. And it is getting bigger.

Larger Brains are very rare as most animals cannot afford it. This is because brain accounts 2-3 percent of the total body weight but consumes +25% of body's energy - even at rest. It is a huge energy drain.

The advent of cooking food - also favoured larger brains.

Since Large intestines and brains are both massive energy consumers, it’s hard to have both.

But if you cook food - the energy requirement of intestines gets way lesser because suddenly the food becomes soft and easier to digest. This led to shortening the intestines and decreasing their energy consumption. This way, cooking - indirectly opened the way to the jumbo brains in humans.