Is it permissible to fast voluntarily every Monday and Thursday and three days of every month with the intention of drawing closer to Allah and reducing sins, if the primary motive is a decreased need for food?

It is recommended to fast on Mondays and Thursdays, due to the virtue reported for these days: deeds are presented therein, the Prophet, peace and blessings be upon him, was born on one of them, and the Qur'an was revealed to him on one of them. It is also recommended to fast three days of every month, which are the Ayyam al-Bid (the 13th, 14th, and 15th), because fasting them carries the reward of fasting a lifetime and removes resentment from the heart. It does not matter if the fasting is due to not needing food or not having it, as the Prophet, peace and blessings be upon him, used to do that.