Each person's organism is different and can tolerate different degrees of departure from nature. My guess on 1-2 is that your organism is just telling you where its limits are at the current point of time. (a) Cooked foods are acidic, raw fruit and veg - alkaline. I remember reading something relating joint stiffness to acidic buildup in the joints. (b) a lot of the literature, esp. the literature from the early 20th c. when people were still way less toxic and industrial agriculture was way less dominant, presents fasting as something that you do, and after you complete it, you have healed -- and it may have worked for them, back in the day. But nowadays, we get both more toxic, and more toxic earlier in life. Fasting may cause detox and healing to begin, but maybe we start so damaged that even that is only a dent and we can allow ourselves much less leeway in what we eat and how we live if we would like healing and rebuilding to continue.