First impressions
Are you put off by him taking food off your plate? Do you think this is just rude? What is your first reaction? Are you disgusted by his behaviour?
What do you do next?
The best thing to do is to make a joke about it. Say something like "You should wait until the second date before you start stealing my food!" Hopefully he will think you are funny and not some kind of germophobe or anything like that. Laugh at yourself but don´t be too blunt about making your point.
What if he doesn´t get the point?
If he doesn´t get the point by your jokey comment then make sure this first date is your last date. Its not your job to teach manners to a guy and you shouldn’t feel responsible for his rudeness.
This is an easy dating moment to solve. Just follow your gut. Remember stay positive and jokey. Always keep a smile on your face and you should be fine. Just remember no matter how cute the guy is if he doesn´t have manners forget it! Unless he is really cute then you can work on those manners over time.