According to Catholicism, is it sinful to refuse food that is put before you, because you does not like the particular food? We suppose that the food served is made for the one who eats it (not in the restaurant, but say for example mother cooks for a child or a cook for the religious)? Is it a mortal sin, and what kind of sin is being committed?
Assuming no sickness* or Church fasting and abstinence law impedes him from being able to eat the food, he commits a sin of ingratitude and gluttony by refusing it.
There are five species of gluttony, which, following St. Gregory the Great, St. Thomas explains Summa Theologica II-II q. 148 a. 4 co., where one seeks
- "sumptuous" or "costly food" (pretiosos)
- "food prepared too nicely—i.e. 'daintily'" (studiose)
- "eating 'too much'" (nimis)
(This is what most people understand by gluttony.)
- "eat[ing] 'hastily'" (præpropere), not at "the proper time for eating"
(snacking, eating between meals)
- "eating 'greedily'" (ardenter), where "one fails to observe the due manner of eating"
(eating too fast or voraciously)
St. Gregory sums this up in: "praepropere, laute, nimis, ardenter, studiose" ("hastily, sumptuously, too much, greedily, daintily").
Gluttony becomes a mortal sin when (ibid.)
the inordinate concupiscence in gluttony be found to turn man away from the last end […]. This is the case when he adheres to the pleasure of gluttony as his end, for the sake of which he contemns God, being ready to disobey God's commandments, in order to obtain those pleasures.
and it's venial
when a man has too great a desire for the pleasures of the palate, yet would not for their sake do anything contrary to God's law
*As was the case with St. Catherine of Siena, for example, an her confessor recounts (Legenda maior pt. 2 ch. 5): "If she forced herself to eat, her body suffered extremely, her digestion would not function, and the food had to come out with an effort by the way it had gone in. It is difficult to estimate the amount of suffering that this holy virgin experienced through swallowing food."
She was not ungrateful or glutinous: "God for my sins has afflicted me with a special kind of illness that makes it impossible for me to eat; I should like to be able to eat, but I can’t. Pray for me, that God will forgive me my sins, which make me have to suffer all these evils."