skeeta - with us - if DD#1 is struggling to eat her dinner but wants yoghurt then we do a "x number of mouthfulls" (depending on how much she has already eaten) - but make it fun, not "you must sit there and eat 5 mouthfulls or go to bed without dinner" iykwim?!

for example: we say "5 more mouthfulls" and hold up 5 fingers. Each finger has a 'secret sound' so after each mouthfull she gets to push a finger down and hear what funny sound it makes (animal noises, random things, raspberries etc!)
or sometimes she likes to choose what sort of vehicle will bring her her dinner - motorbike, helicopter etc
HTH