Before we eat even the smallest bit of food, Jewish law requires us to say a blessing thanking God. Mishnah Berachot lists the various berachot: "How do we bless on fruit? On fruit of the tree, we say, 'Who has created fruit of the tree'" etc (chapter 6).
Unlike Grace after Meals, which is commanded in the Torah (Deuteronomy 8:1), Birkot Hanehenin ( "enjoyment blessings") are rabbinically ordained. The Talmud mentions several biblical verses as possible origins of the obligation to say Birkot Hanehenin but dismisses them all (Berachot 35a). Ultimately, the rabbis conclude: "It is reasonable to say that it is forbidden for a person to enjoy anything of this world without saying a blessing."
In other words, we do not need the Torah to tell us a fundamental of menshlichkeit, to say thank you to God before enjoying the world's bounty. Blessing on food are a way of constantly remembering "the earth is the Lord's".