I've heard that not all foods veg*n foods styled to resemble meat are healthy; some are quite processed, high in sodium, etc. What are the main health concerns when eating fake meat? How can I identify healthier meat substitutes?
The only way to really know if food is healthy is to cook it yourself. Meat substitutes such as pre-made vegetarian "burgers" or "sausages" in particular are high in preservatives and sodium. They're also very costly compared to other vegetarian options.
I'd recommend trying to cook vegetarian dishes that are not trying to "replace" meat such as lentil curries, Tex/Mex with beans, or Asian stir fries (with Tofu). If you're trying to avoid meat, substituting is rather strange and may actually make it harder to adapt to vegetarianism. Many long-term vegetarians don't remember what they're missing and even find meat (or substitutes) unappealing.
If emulating meat dishes is your thing, I'd recommend trying the recipes of Lukas Volger. I found his cookbook really good and it looks like they've released pre-mix products on the web (although likely only for sale in the US). They're more about preparing burgers and like that have the same style as meat dishes, rather than emulating the flavours.