This is my concern: I'm not obese. But I have quite a bit of fat on my body and would like to see it off. I've researched that the body enters into a state of ketosis after all other immediate sources of energy (unused carbohydrates, glycogen in the liver, etc.) have been depleted - a state which may take a few days to enter into.
Were these mentioned individuals significantly overweight, or at the very least, had a significant body fat percentage (I would classify this at 30% and 35% for males and females, respectively)? I realize even with these stats, 40 days (much less 60) might be a stretch.