I realize this has been discussed in a great amount already, but I thought I'd just give my thoughts. Sorry in advance is I sound preachy.
I am a strict vegan. I do not eat meat, fish, dairy, eggs, honey, or any animal products or by products. I know what even minute animal products are, and try to avoid them by reading labels, and such. The products I use are vegan to the greatest extent I can find. I don't wear leather, wool, cashmere. And, all of my other products I try to buy vegan. At home, I do not expect my family to prepare two meals, so I make my own food, and no one is bothered.
In my opinion, if you eat meat, you are inadvertently increasing the demand for meat. And, you are indirectly contributing to the death of animals. Even if you eat dairy, you are still contributing to the suffering of female dairy cows, and the killing of male calves for veal. You may not think so, but even if meat is offered to you, or it is already "dead", you still are perpetuating the demand for meat. And, in my opinion any of that is breaking the 1st precept.
Not many people would be offended if you denied an offer of meat. I do it all the time, and so far no one has been bothered. But, would you rather innocent beings die for you, or take the risk of someone maybe not liking you being vegetarian or vegan.
However, I try as well not to let it become a distraction. Most of the things I mentioned are second nature to me. So, none of it bothers my day to day life. If anything would be causing you harm, or causing you to become unmindful, do not partake. Taking things in small steps is best.