Other forms: overconsuming; overconsumed; overconsumes
To overconsume is to use or eat too much of something. If you overconsume dark chocolate right before bed, you'll probably have a hard time falling asleep.
To consume is to use, spend, or eat, from the Latin root consumere, "to use up or eat." Add over to that, and you've got a word for using (or eating) more than what's needed. A country might overconsume natural resources, leaving areas bare of trees or draining lakes to irrigate crops. And a person can overconsume by spending too much and going into debt — or they might just overconsume potato chips, giving themselves a stomach ache.