What is the meaning of Temperance? Moderation/self control. Also staying away from harmful substances, not only food and drink, but any daily activity, that will put to much pressure on the body.
Being temperate will allow the mind to control the body, what to takes in, how much, what to avoid. Over doing anything can cause the body to become diseased, like wise ,under doing will have a similar effects. The body is a unit, it's organs work together to compliment each other, so being temperate in all things will allow the body to work together, physical, mental and spiritual.
1 Corinthians ( 10 : 31 ) Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God.
Romans ( 8 : 28) And we know that all things work together for good to them that love God, to them who are called according to his purpose.
As God intended