Not true. They either get really skinny or really fat, it depends on the person, the amount of the drug they do a day, and the method of use: insufflation (snorting), smoking, intravenous (mainlining, not skin popping). I've seen people go from small fat to morbidly obese in under a year while shooting heroin. Heroin makes you crave sugar, and alot of people will stuff themselves with all the sugar they can afford after nodding out. I've seen other people lose half their body weight. If you had no self control prior to using, heroin will only exacerbate the problem as it gives you an intense euphoria and carefree attitude.  Not trying to call you out our anything, it's just a common misconception that they're thin. Also, that drug doesn't care about what social class your in. It's not just the homeless guy on the corner anymore. Habits get expensive and where I'm from a gram of good heroin is more than a gram of blow.  Source: Was a heroin addict for 5+ years and grew up in a wealthy suburb outside of NYC on Long Islands Gold Coast. Been clean for two years. It's so bad there now that there's an epidemic and to get into treatment you will wait a minimum of six months for inpatient.