Toyota Repair: Toyota 86 Tacoma 22r, worn piston rings, 4 quarts

Question
Truck uses up to 4 quarts of oil per tank of gas, but there are no oil leaks on motor/or from exhaust. Any ideas?
Also......does not smoke.  

Answer
That does seem excessive, since you normally get about 300 miles out of a tank of gas. There are only two ways that an engine uses too much oil, there is a leak or the engine is burning it, the leak could be internal where the oil is going into the cooling system, if there is no oil in the cooling system and there is no external leak then the engine must be consuming it which is normally due to worn piston rings.