Permission of Parents for Performing Recommendable Fasting

I was a follower of Imam Khomeini (r.a.) in religious rulings and I have remained his follower after his demise according to your Fatwa; According to Imam Khomeini, if performing recommendable fasting causes harm to one’s parents and grandparents then it is not permitted. However, considering the fact that I am single and I’ve found performing recommendable fasts as the only way of abstaining f r o m doing the prohibited act of fornication and my parents do not agree with this, then is it permissible for me to perform recommendable fasting in this conditions without the permission of my parents?