Daniel was the man even when he was a teenager! He had decided beforehand that he would honor God in the foreign land.
Notice what he didn't do.
He didn't get in the face of the guy in charge. He didn't make a scene. He didn't embarrass those on the king's staff. He was very respectful and he even gave the guy a test time. He told the man if after ten days of eating just vegetables and water, if he looked worse than the other young guys, he'd eat the king's food.
He also was concerned about this guy in charge. He worked with him.
After ten days he and his three friends looked better than the rest!
God never fails. If we honor God God will be glorified.
An interesting note to this story (and if you've never read it go to http://www.biblegateway.com/passage/?search=Daniel%201&version=NASB and read it now if you have time...You can even pick a different version. The Message one is a great one to check out) is that Daniel and his three friends were not the only young men from Judah. Daniel 1:6 says, Now among them from the sons of Judah were Daniel, Hananiah, Mishael and Azariah.
So what did the other young men from Judah do? I don't know for sure but it seems they went ahead and took on the practices of the foreign lands. And their names have been forgotten...