Is fasting an effective method to overcome substance addictions?

I recently watched a testimony of a man who reports the results of a 40-day water/juice fast (no food). The individual claims to have been addicted to drugs for 22 years, including marijuana, cocaine, mushrooms, LSD, ecstasy, prescription pain pills and alcohol. He went cold turkey, abstaining from both food and addictive substances during the 40-day fast. After the fast, he reports complete freedom and no relapses.

This particular case raised my interest in the potential benefits of fasting in the addiction recovery arena. After a quick search I found this site which claims that:

Fasting is by far the most sophisticated willpower workout available. If you get good at fasting, you can learn to control every other aspect of your life. If you get good at fasting, you can overcome any addiction, not matter how deeply imbedded. Medically, fasting has been found to rapidly dissipate the craving for nicotine, alcohol, caffeine and other drugs.

Is it true that any addiction can be overcome with the skills learnt by fasting? Are there studies on the effectiveness of fasting for overcoming substance addictions or any addiction for that matter?