User blog comment:DancePowderer/Where There's Vinsmoke, There's Power Part 2/@comment-208.96.127.154-20160203162719

Sanji ran away. But I don't think that he chose specifically to be a chef; he just stowed away and had to work to stay aboard when they found him. If you recall the scene of him on the Orbit, he's not super knowledgeable or enthusiastic. He only starts to really learn when he starts the Baratie with Zeff.

For this reason, I doubt the "food = life" thing will come up as anything more than starving with Zeff.

After all, assassins often use poison, so food can be used to kill too. Although, that may have been the argument that caused Sanji to run away ...

At any rate, they probably tracked him to the Orbit, but when it was wrecked, they thought he was dead. Then, when the real picture came out in his second bounty, the family pulled some strings to have him returned to them alive.