I exercised for years. I was very active. running, mountain biking, weight lifting, etc. My diet was decent. I ate a wide variety of foods, no fast food and very little junk food. Usually a small breakfast, decent sized lunch and no dinner.
I remained overweight and felt terrible.
I had significant joint pain and I would get headaches after vigorous exercise.
It got worse year after year despite exercising.
It turns out I have an autoimmune disease. It took several doctors and much of my own research to figure this out (our medical industry sucks). No doctors know why I have it or how to deal with it. And as I've proven to myself, NO reasonable amount of exercise will help with this "disease".
My conclusions are that the autoimmune response is a reaction to toxins.
I believe my conclusions are correct as since I have been fasting my health has turned around. My antibodies are consistently getting lower. Joint pain is gone. Body temp back up to normal. Headaches after exercise much better. Skin issues gone. Lots of excess weight gone. Anxiety and gloom (not really depression) gone. I could go on on the health effects of fasting.