As long as the carbohydrate is the naturally occuring milk sugar (lactose) present in all dairy produce, (and not something added by a manufacturer) then fat free greek yogurt is fine (in fact I get through at least half a tub-full everyday)
I just tried this with an ice cream maker! It makes them a froyo (frozen yog / whippy) consistency...I could probably make it more solid by popping it in the freezer for a while after but hey! Who can wait for that? Super yummy! Had mine with banana and two mini meringues. Going to try every flavour I can now!
Sorry no muller rice....its carbs..... and they recommend natural yoghurt and add your own flavouring but I eat muller lights vanilla and toffee and lose but if I stall I'll have to stop eating them hope that helps x