Many people have heard the phrase that "your body is a temple," but do you know the origin of the whole quote?
19 Or do you not know that your body is the temple of the Holy Spirit who is in you, whom you have from God, and you are not your own? 20 For you were bought at a price; therefore glorify God in your body and in your spirit, which are God’s. - 1 Corinthians 6:19-20So we actually have a spiritual reason to be taking care of our bodies. Part of that includes eating the proper foods - not junk food. Part of that is finding an exercise (or several) you enjoy, to exercise the body you've been given. And if you have difficulty with doing those things, perhaps making note that the body we have is just a loaner, and we need to turn it in, in good condition when we're done, may help you do that.
There was an interesting experiment that a high school student did. It's worth a watch. Some of the language can be a bit objectionable, but think about how teenagers can occasionally react to things. And how we ourselves react at times.