Maybe this is why Christ gave the example of fasting in isolation. Fasting during our daily routine can do wonders, as I've experienced first hand. But sometimes it's not enough.
Also, Dr. Shelton had turned his back on faith. When in need, we are to turn to the "Great Physician", Christ, who through all things consist.
We had a boy in our church with a cancer tumor the size of a lemon. The doctors all said that he was going to die. The pastors laid hands on him and prayed annointing him with oil, as the Bible commands, and the next day he was totally healed. The doctor was speechless.
Fasting is amazing and wonderful, but it works best when we involve our Creator.