Question

Regular heavy drinkers usually have to drink less in order to obtain the same effect

Answer 1

That is false. Alcohol is a drug, and the more you use a drug, the more you have to take to achieve the same effects as your body gets used to it.                 
(You have to take more and more each time to achieve the same affects as the first time)

Answer 2

Actually, the heavier a drinker you are the more you need to get so that you can get the same effect of getting drunk as a normal less heavy as a drinker who drinks less and still gets drunk.