Gratitude vs Ingratitude
[Al-Qur'an 39:7, Translation: Literal (word by word)] If you disbelieve then indeed, Allah (is) free from need of you. And not He likes in His slaves ungratefulness. And if you are grateful He likes it in you. And not will bear bearer of burdens (the) burden (of) another. Then to your Lord (is) your return, then He will inform you about what you used to do. Indeed, He (is) the All-Knower of what (is) in the breasts.
Gratitude for Grains and Fruits
[Al-Qur'an 36:33, 34, 35, Translation: Literal (word by word)] And a Sign for them (is) the earth dead. We give it life and We bring forth from it grain, and from it they eat. And We placed therein gardens of date-palms and grapevines, and We caused to gush in it of the springs, That they may eat of its fruit. And not made it their hands. So will not they be grateful?
Gratitude for Cattle
[Al-Qur'an 36:71, 72, 73, Translation: Literal (word by word)] Do not they see that We [We] created for them from what have made Our hands, cattle, then they [for them] (are the) owners? And We have tamed them for them, so some of them - they ride them, and some of them they eat. And for them therein (are) benefits and drinks, so (will) not they give thanks?
Grave sin to not to mention God's name
[Al-Qur'an 6:118, 119, 120, 121, Translation: Literal (word by word)] So eat of what (is) mentioned (the) name (of) Allah on it, if you are in His Verses - believers. And what for you that not you eat of what has been mentioned Allah's name on it, when indeed, He (has) explained in detail to you what He (has) forbidden to you except what you are compelled to it. And indeed, many surely lead astray by their (vain) desires without knowledge. Indeed, your Lord, He (is) most knowing of the transgressors. Forsake open [the] sins and the secret. Indeed, those who earn [the] sin they will be recompensed for what they used to commit. And (do) not eat of that, not has been mentioned Allah's name on it, and indeed, it (is) grave disobedience.And indeed, the devils inspire to their friends so that they dispute with you, and if you obey them, indeed, you (would) be the polytheists.
Though the above quoted verse from Surah Al-Anaam (Q6: The Cattle), with reference to context, seems to be about meat being slaughtered while pronouncing the name of Allah upon it, the verses quoted from Q36, Surah Ya'sin, exhort us to be grateful for all the food we eat.
We our told that our dear Prophet's sunnah was to begin eating food with the name of Allah, and after eating, to thank Allah for it.
To compare 50+ English translations of the ayaat quoted above, please follow their links.
Some links for ahaadith regarding etiquettes of eating food: