> Conclusion: It can be reasonably assumed that this subject have had protective effects from his yearly fasting.

No, it bloody well can’t.

> [before his first fast he] smoked around 10 cigarettes per day [then he] stopped smoking with no relapse after his first fast.

Sure, definitely the fasting, not the cutting out the literal cancer-generation sticks or anything else.

If I read that right, he wasn't actually "fasting," as defined by the complete absence of calories.

Instead, he regularly went on a very-low-calorie diet at this German clinic.

More data on fasting should be available from Ramadan - annual muslim month of fasting. (The article references Ramadan in passing.)

Ramadan is repetitive partial daily fasting, so less valuable than a long term continuous fast.