The problem is that pretty much anything we do differently from our ancestors harms the brain while it is still growing. Using sugar casually probably harms the

The problem is that pretty much anything we do differently from our ancestors harms the brain while it is still growing. Using sugar casually probably harms the brain just as much as smoking pot casually does. Sitting all day harms the brain. Heck, living in certain parts of the country can harm the brain. I agree with limiting pot use until the age of 18 but that applies to everything else that's unnatural as well, such as sugar and salt (assuming we set a limit that's healthy based on ancestor's diet and no BS chemicals). So many things changed in the last century that our bodies can't adapt quickly to support our diet and lifestyle. It takes tens of thousands if not hundreds of thousands of years for the body to adapt to the environment we're living in and how we're using our bodies. That's why obesity is starting to become #1 problem for the whole world as we continue to go further into the information age.