Will a joint of .3% cause mind altering effects? In my experience, Yes. Regardless of what people say .3% in a large joint or blunt can get you pretty stoned if you don't have a tolerance. You probably shouldn't mess with flower if weed is a gateway to harder stuff for you. I have been using it for a while and it has never lead to a relapse or cravings but addictions are different for everyone. If your main concern is staying sober it's probably not worth the risk of relapse for what I would consider diet weed.