Are your tastebuds worth more than an animals life? Watch
Vitamin B12 Only found in meat again (though I could be wrong on this one) causes abnormalities in the blood if not taken in at a high enough rate.
A lack of Vitamin D3 appears to lead to an increase of; cancer, heart disease and depression.
Clearly, meat is very, very beneficial and that's just a few examples. It's very hard to live a healthy life without some supplements to replace meat. However, I'm not saying it's impossible.
I would strongly disagree that "It's very hard to live a healthy life without some supplements to replace meat" as such supplements can be found very easily and vegetarian/vegan alternatives eg. tofu usually contain iron, protein and other necessary nutrients found in meat. However I will admit that these dietary choices aren't particularly accessible to people outside middle and upper classes, just compare a £1.99 burger from McDonalds to proper meat free food from a supermarket or homemade meals for example.
This point also assumes that people with an omnivorous diet are healthy and eat a balanced diet. I find this a funny phenomenon, the general population don't make such open and 'concerned' comments about nutrition until someone says they are cutting meat and/or animal products out of their diet, despite research repeatedly showing vegetarians and vegans on average are much healthier, eat a more balanced diet and have lower rates of suffering from conditions such as cardiovascular disease.
As for OP, it depends on their reasons for becoming vegetarian, some simply don't like the tase of meat anyways, for others (like me) the detrimental impacts of mass consumption of meat on the environment are enough (reduce the demand, reduce the supply) and if you care strongly about animal welfare, I'm sorry but you absolutely can not continue to consume meat without being plagued by hypocrisy. It is hubris to claim humans can "control" the food chain in a sustainable manner. Sure, if everyone went vegan overnight it would be a huge problem but that will never happen and there will always be a large portion of the population who continue to consume meat. instead, the slow (which it is) movement towards vegetarianism/veganism will reduce the demand and therefore less meat will be supplied, animals wouldn't be bred and killed in as large quantities as they are but populations would not "boom then collapse".