Mullers used to be ok, but the sugar content must have stalled people's weight loss.
Over here, we can get 0% fat fruit FLAVOURED yoghurts and those are the ones he refers to in the book (which is little more than a translation of the original...).
Total 0% and flavour yourself is the best way... or count as tolerated each Muller in cruise and keep an eye on the scales. While you still lose, carry on!