Felt like I was watching Good Eats 1. Cut away all of the visible fat, then place steak in a large resealable plastic bag along with 1/2 cup red wine and 1/2 cup extra virgin olive oil. 2. Allow the meat to marinate for 24 hours, flip the bag a couple of times. 3. Take the steak out and drain for an hour, throw away the marinade. The wine works as a solvent to suck out a good amount of the sat. fat in the steak, which will be replaced by the monounsaturated fat. Of course, this won't change the fat content of the steak, just the type. I don't konw if just using the wine would simply defat it.