I wouldn't mess with gum disease. If there is bone loss you need to take action right away and not let up. Fasting helps the immune system, but we are talking about ANAEROBIC bacteria below the gum line(read:you can't kill it by standard brushing and flossing) you need to access the periodontal pockets with special protocols.
Periodontal Disease Treatment Guide Gum Disease? Avoid Gum Surgery Kit - Save your teeth!
Good luck