At the most basic level, you are not truly free if you do not have the right to put into your system whatever you want. Who gets to decide which chemical compound is legally consumable and which isn’t, and by what argument?
If the results of whatever illegal substance you put into your system endanger the lives of others, then there is your line in the sand. If you eat 20 Big Macs a day and still want taxpayer funded “free” healthcare, then the rest of us have a problem.