Complex sentence: For 10 days, they are permitted to eat just vegetables, and at the end, the guard is surprised at their good personal appearance and physical and mental health, compared to those who had indulged in the royal foods.
Split into simpler sentences: For 10 days, they are permitted to eat just vegetables. At the end of the 10 days, the guard is surprised at their good personal appearance and physical and mental health, compared to those who had indulged in the royal foods.