Nuts do have sugar in them. But, just like fruit, if you eat a little, it's OK, because of how much fibre etc you get, and how much you'd have to eat to end up with huge amounts of sugar. If the book says a food is OK, check the ingredients list. If all that's in the bag is nuts, then it's OK, because nuts are OK, and the sugar you see, is just in the nuts. That's probably always going to be true ( unless the nuts are in rocky road and that's bad :P ), but that's a general rule of thumb. If your yoghurt contains milk and culture, it has no added sugar and the sugar you see, is lactose in the milk, for example.