It didn’t affect my cognitive function when I have eaten that way.
In fact, my blood sugars were under very good control and I required less insulin. Also good.
I exercise every day too and never felt that I had to eat a lot of carbs to get through a work out.
If I ever feel I have to do that, I must be in training for an Olympic event. ;)

No. Your brain burns sugar like an exotic V12 supercar from the 70’s burns gasoline.

I will tell you truthfully that out of the few people I know to be endowed with genius, not a single one of them eats right. In fact, I’m all but convinced that between bad diet and genius it is impossible to discern which characteristic drives the other.

Best food for cognitive function is fish i.e. Salmon, Trout, Halibut.

No. No food has been shown to be best for cognitive function.

Doubtful. Sugars feed the nervous system. When you deprive your body of sugars it has to convert muscle and fat to continue to try to give the nervous system what it needs.

Low blood sugar can lead to loss of good cognition, this is a risk people with hard to control blood sugar levels have, although I think it’s thought of as a temporary thing until they correct their blood sugar with some sugar.

I guess “low” carb begs the question, how low? If you are constantly hitting the wall (depleting glycogen storage) that’s not good in my opinion. Not good for many things.

I’m no expert though.

It seems to me that a lack of carbohydrates cannot improve cognitive abilities. At least at that moment when you lack them. But perhaps this will have positive consequences in the future.