yln,
if at home, i will just leave him to throw tantrum there and ignore him. yes, he still stand/kneel or sit on ikea stool to eat. if he kicks the stool away, you know he is almost there or don't want to eat liao. if he wants to play and don't want to eat, i will not allow him to play. i will tell him to finish his food before he can go and play. then he will be whining at the table but will still finished at least half the portion, sometimes all and forget about the playing liao.
if outside, i will ask him to stop or i walk away. if refuse to stop, i will walk away loh. most cases, he will follow lah. if he don't follow, just hide at a corner to see how he react loh. after sometime then i will appear but still at the far distance. know that he saw me liao, i will signal for him to come and i hug him. he will then cry and walk towards me to carry him. but before i carry him, i will ask him to stop crying. if he still don't stop then just stand there or walk away again. usually by this time, he will stop and control his crying then i will carry him. then slowly talk to him of why he shouldn't be like that while i carry him.
meal time outside, usually he will sit there to eat. if refuse to sit there to eat then i will get drink for him to make him sit there loh. drinks may not necessary be sweet. even ice cold plain water will do also.