Whether gluttony is a sin?

Objections

Objection 1 : It would seem that gluttony is not a sin. For our Lord said (Mt. 15:11): "Not that which goeth into the mouth defileth a man." Now gluttony regards food which goes into a man. Therefore, since every sin defiles a man, it seems that gluttony is not a sin.
Objection 2 : Further, "No man sins in what he cannot avoid" [*Ep. lxxi, ad Lucin.]. Now gluttony is immoderation in food; and man cannot avoid this, for Gregory says (Moral. xxx, 18): "Since in eating pleasure and necessity go together, we fail to discern between the call of necessity and the seduction of pleasure," and Augustine says (Confess. x, 31): "Who is it, Lord, that does not eat a little more than necessary?" Therefore gluttony is not a sin.
Objection 3 : Further, in every kind of sin the first movement is a sin. But the first movement in taking food is not a sin, else hunger and thirst would be sinful. Therefore gluttony is not a sin.