My firsthand:
I researched the keto flu and made sure when I purged my pantry to get some sodium & potassium supplements. (I can’t tolerate magnesium supplements but made sure I had magnesium rich foods.)
I started taking 1 gram of sodium three times a day, the next day I was up to 2 grams three times a day. Potassium 20 mEq twice a day.
When the carb withdrawal hit me hard (don’t yell at me, lol) I was so nauseated I let one sugar cube (counted in my carbs) dissolve on my tongue. Did that once a day for three days.
Drank gallons 3-4 of water/day (still do). I bought Ketostix the day after I started and already had moderate ketones in my urine.
My carb withdrawal lasted 4 days. Mild temp, no energy. I used to eat nothing BUT carbs. I’m interested to see what others have done to prevent or treat their carb withdrawals. I can tell you I felt lousy enough that I am terrified to go over 20g/day and knock myself out of ketosis. Starting Keto was super hard for me but I am loving the changes to my body, mood, and energy.