I also eat whatever people serve me if I visit them. At some point, but not during the meal, I make sure to let them know that I'm a vegetarian. Most people honor me by serving and eating vegetarian meals when I visit, some others still serve me meat. The last time I ate meat was at my step brother's house, in November, when his wife served me a meat stew for supper. I ate it, but it was difficult for me to eat it because it has become repulsive to me: the previous time someone had served me meat was several years before that. I ate just enough to be polite. I don't tend to think of eating a dead animal someone serves me as part of their normal routine in terms of karma, but that may just be a result of having chosen to quit eating animals before I chose to become a Buddhist. OTOH, there is much in both Sutta and Sutra to support the approach I use.

Your situation is far different from the "where's the meat-a-tarian option?" mindset that I'm addressing. For omega III I use hemp seed, but that's neither here nor there. Your decision is based on a health concern rather than on a simple desire (or shamanistic intention) to eat flesh. I never tell people they should stop eating meat. It's not really my business whether someone does or not. My curiosity is about people who choose to be Buddhists but see no problem whatsoever with eating animals. It's something I simply don't understand.

I'm curious what motivates someone to become a Buddhist who doesn't see any problem with participating in the massive suffering caused by the animal breed-and-slaughter industry. Is it purely for one's own freedom from suffering? Not saying it it, just asking. Or maybe a feeling that it doesn't matter? The latter I would call nihilism based on desire rather than emptiness-awareness, but I could be wrong. If it is from a complete awareness of emptiness, though, why not demonstrate compassion by simply not eating animals?