One of the problems among Christians today is that very few are willing to say that the act of overeating is sin. It is socially acceptable to overeat and so most would rather say that overeating is a "weakness," or a dietary problem that may be corrected by changing foods, a glandular problem, or that we simply "have a big appetite"...etc
Overeating is a sin for the following reasons:
•Whether we eat or drink, or whatever we do, we are to do to the glory of God (1 Corinthians 10:31). God is not glorified when we evidence a lack of self control in our eating habits.
•My body is the temple of God (1 Corinthians 3:17, 6:19). The temple of God is not to be destroyed or defiled. Overeating or other sinful eating habits defiles the temple and if continued in can lead to its early destruction.
•Sinning leads to slavery (John 8:34). Overeating, like any sin, becomes addictive and can be extremely hard to overcome.
•Jesus told us to take up our cross daily (Luke 9:23) and Paul told us to crucify the desires of the flesh (Romans 8:13, Colossians 3:5). To overeat is to gratify the cravings of the flesh, rather than to crucify them. This is sin. This is not to say that it's a sin to eat when hungry. The sin of gluttony is the habit of overeating. Food is not evil, and eating is not a sin.
•There are many passages of Scripture which speak of the sin of gluttony; the Bible instructs us to avoid the path of the glutton (Proverbs 23:20-21) and to "put a knife to our throat" if we are given to gluttony (Proverbs 23:2). (The Merriam-Webster Dictionary defines gluttony as "excess eating.")
"This life, therefore, is not righteousness, but growth in righteousness, not being but becoming, not rest but exercise. We are not yet what we shall be, but we are growing toward it. The process is not finished, but is going on. This is not the end, but it is the road. All does not yet gleam in glory, but all is being purified."
“Therefore, since we have a great high priest who has gone through the heavens, Jesus the Son of God, let us hold firmly to the faith we profess. For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are – yet was without sin. Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.” 