Dukan keeps changing their minds about yoghurts LOL ... when i first started i was eating toffee or vanilla muller , asda ff vanilla, WW vanilla & toffee and it didnt affect my loss but the sugar content in them may.
The best one is total 0% add your own flavour & sweeten... some of the other supermarket ff natural ones are ok too. I make my own yoghurt now and keep mullers for treats (they do taste too sweet now though) I also have a couple of tesco ff greek yoghrts on standby incase i run out of homemade