[anthomtb]

I did keto for a few months a long time ago (2010/2011). This was early in my career and long coding and debug sessions were a normal part of my day-to-day.

There was zero impact to my work focus, positive or negative, from cutting nearly all carbohydrates out for several months.

I am curious were you heard or learned that "sugar is really important for focus". Just a vibe, perhaps?

[lfliosdjf]

Personal experience. Then I found many well known programmers shared the same experience online. It feels deliberate work without sugar. ie. if coding = work + fun. without sugar its just coding = work. It does not get any better after 3 days or so too.

[GloamingNiblets]

It might feel good but spiking your blood sugar isn't healthy for you, and the crashes afterwards will get worse over the years. Improving metabolic health might be a better long term solution; have you explored how endurance or high intensity exercise affects your focus?