system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why did doctors used to recommend heavy drinkers switch from vodka or gin to whiskey under the guise that whiskey was healthier?

I've read that Ian Fleming's doctor recommended that he switch from a fifth of gin a day to bourbon. Dean Martin's apocryphal last words were "I never should've switched from bourbon to martinis." Why was whiskey regarded as healthier?
gpt
I can't speak for doctors in the early 1900s, but Vodka and Gin go down much too easy and provide far less of a hangover due to their makeup (they are distilled, often, 3-5 times, removing a greater portion of the impurities that cause hangovers).  This is why the greater portion of alcoholics are Gin or vodka drinkers.
  
Bourbon, however, punishes you if you drink it too much, making you realize the damage you've done. 
  
Source: career bartender.