Most meat needs a certain amount of fat in it to prevent it from drying out during cooking. Barbeque connoisseurs will never look for lean steaks; they look for steaks with good marbling.
Barding is a fancy word for a technique you probably already practise. You tie a piece of fat, such as suet or American-style bacon (streaky bacon), around a piece of lean meat or poultry so that the added fat compensates for the absence of fat to keep the meat or poultry moist. A few minutes before the meat is done, you remove the fat to allow the meat to brown.
If you use American-style (streaky) bacon, you can salt the meat a bit less as some of the salt from the bacon will go into the meat.
You may want to use unsmoked bacon (as opposed to smoked bacon) with beef.