The yoghurt is typically only 2% fat. Boo!! That means lot of of unnecceasry milk proteins and lactose etc. Cream is around 40% fat and butter 80%+ fat :-)
I feel animal fats are much more naturally occuring then oils and therefore are more easily processed. I understand there are other benefits from these oils but i dont think they work as well as a source of fuel.
This diet has also significantky improved my bodies ability to process dairy :-)