Is it insulting to those waiters/waitresses at the restaurant if you only take a few bites out of your meal?

A good waiter would be concerned with what little you ate, and ask, was everything ok. If you reply yes, then it should not matter after that the reason why your taking your food home. If they ask, you can respond that your just not that hungry and are taking the food home to eat later. I've done that too, where I ate beforehand, and was not hungry, but would like to eat it at a later time.