Will you be giving me a 100% pure, regulated, pharmaceutical grade dose of heroin at the price it takes to produce it in a legal market? Or will I be using an adulterated mystery packet of unknown substance and purity off the street that is orders of magnitude more expensive due to the profits generated for barbaric criminal enterprises along the supply chain?
Let's be honest, food (sugar) and alcohol are in a totally different league from hard drugs. They're not even relevant to the discussion here. We can do an experiment. I'll take 2 shots of alcohol every day, my friend will drink 3 sodas a day (100+g of sugar), and you can shoot up heroin every day. Let's see how we're all doing in a year.