Eating potatoes isn’t probably a good idea to prolong your fasting effect. You want to avoid both carbs and protein. You want to avoid carbs to lower your insulin level, and you want to avoid protein to suppress mTOR. Having said that, if you are eating raw potatoes, it doesn’t raise your blood sugar level so quickly as cooked potatoes, so it might work.
Dr. Mindy talks about it here. https://www.youtube.com/watch?v=6f1X1PY6O6Y

No, I didn’t. I drank organic black coffee during my fast, and I still do. I drink black coffee or green tea. Some say that water fast is better, but both coffee and green tea can activate autophagy, so if they make it easier to cope with fast, I think their merit surpasses the demerit.

Also, what about eating raw potatoes? I’ve been doing this but it’s probably not a low carb food. Still, it should be low protein to keep you in the autophagy state, yes?

Thank You so much for you comments. I need to try and follow your example. It’s hard sometimes. Did you eliminate coffee from your diet?

Thank you for your comment, Qui Jin. No, I am not. The purpose of having only vege for lunch was to prolong the effect of fasting and the less I eat the better it was. I am not doing it now anyway. I am doing 24 hours fast instead. So, I do 17 hours fast 4 days a week and 24 hours fast 1 day a week.