There's definitely a huge benefit to early concussion response and PCS recovery from simply removing metmike07's foods (refined carbs and processed sugars) as they ultimately lead to neuro-inflammation in most people.

For early concussion response, I don't think there's a benefit to a keto-diet. Optimal fat metabolism takes time to develop if you normally rely on glucose for energy. Since metabolism becomes impaired right after head impact you'd want to give the brain an easy glucose source from low-inflammation foods (ie. real unprocessed and low-glycemic foods).

But for PCS recovery, I think a keto-diet can be beneficial for improving PCS related metabolism dysfunction and reducing neuro-inflammation. The science and research that I rely on hasn't definitively shown this, however the current science being published seems to be leading down this path.

There's some positive research in other fields like Alzheimer's research that I think we 'post-concussed' heads can draw from.

I've personally cycled through a few types of keto-diets, including fasting and mct-oil induced states, I found it to be beneficial for reducing brain fog and enhancing cognitive function which directly resulted in a big improvement in my office work performance.

I would promote the keto-diet cycling as a beneficial tool for people who are "stuck" with PCS and looking for something to get their recovery out of a rut.

Some good reading:

1) This study provides a solid description of the cascade of events following a concussion:
The Neurometabolic Cascade of Concussion

2) This study provides some information on keto-diets and TBI:
Ketogenic Diet - Nutrition and Traumatic Brain Injury - NCBI Bookshelf

3) This 2017 study from the Alzheimer's research field showing benefits from keto-diets:
Ketogenic diets and Alzheimer’s disease - ScienceDirect

Cheers

Hains