Marinating Meat

Does marinating meat affect the duration required to cook the meat under the pretense that the temperature and method used to cook the meat stays unchanged from that of an un-marinated piece of meat originating from the same species?

Um, just to get the obvious question out of the way: Is there a reason you're asking that here vs a cooking thread somewhere?

has a point, but get the answer out of the way, it depends. Some marinades tend to char or burn if you cook them at too high a heat and some marinades can actually reduce cooking times because they've chemically cooked the meat a little bit before hand (especially acidic stuff like citrus juices).

Short answer:

It depends on the marinade. Some marinades using certain acids (citric as mentioned is one) do cause a cooking effect inside meats that reduces the time the to cook for certain toughnesses and textures (though it does nothing for internal temps). Some can actually prolong the cooking process by providing a barrier between cooking the meat and cooking the marinade. In those they usually meld and you gotta heat up the marinade before the meat truly starts cooking. The difference is usually no more than a few minutes. But in those cases as mentioned earlier, you gotta be careful, some of those marinades can burn or char quite easily.