Glucose spikes and food sensitivities are unique to each individual. Doctors do not have much, if any, training in routine medical school about nutrition, foods and how they effect autoimmune illnesses. A nurse assigned to me related the story of her sister who had autoimmune and thyroid cancer. After having her thyroid removed a naturopath doctor helped her discover her food sensitivities. Once she avoided those foods, she no longer had issues.
A lot of people who start following a whole food plant based, low-fat diet with no sugar, caffeine, processed foods begin to have less pain and feel better. That is what I’ve done. The other day I deviated from protocol and the pain level returned.
There are a lot of articles and YouTube videos on the effects of sugar on autoimmune disease. The issue is the fructose portion (sugar is 50% glucose + 50% fructose). Look into it.