Complex sentence: When he had not eaten, his skin would hang so loosely that he could wrap the fold of skin from his abdomen around his waist, and when full his abdomen would distend "like a huge balloon".
Split into simpler sentences: When he had not eaten, his skin would hang so loosely that he could wrap the fold of skin from his abdomen around his waist. When full, his abdomen would distend "like a huge balloon".