From the comments section of this post by
trickster_
"-Also, the commenttheusual linked about Obi-wan's relative age between ROTS and ANH and all the hookers and meth he must have been doing? Yeah. It's the only explanation.
Don't forget the booze. The tons and tons of booze. The booze so strong that one time Zaphod Beeblebrox walked into the Mos Eisley Cantina, took a whiff of Obi-Wan's drink, and backed off saying, "Whoa, man. Whoa. That's just freaky. Whoa."