I don't eat a great deal of dairy products, but when I do I love full fat yoghurt and full fat cheeses. I don't have a strong opinion, but I'm not convinced that less fat is healthier. Seems to me I feel full faster and eat less when I eat something with more fat. Sugar is a whole different animal, many yoghurts have massive amounts of sugar in them. I didn't notice that until I started buying plain yoghurt and adding jam or marmalade myself. I had to add so much, to get anywhere near the sweet taste of the pre-sweetened ones.