Lama Ole’s answer:
That depends on one’s level of meditation. On the highest level, you can meditate on everything—on diseases, on suffering and difficulties, on tiredness, and so on. Everything can be transformed and used as raw material for meditation. Most of our rinpoches are in a bad state of health. They eat the wrong things and don’t really take care of their bodies, because from a certain level of meditation on, everything is pleasant—sickness, pain, everything is enjoyable because no matter what happens one just sits there and experiences joy.