Man lives by the word of God.
Earthly food is necessary for human existence, but it is the word of GOD that gives life.
GOD told Israel that He allowed them to go hungry during the exodus and wilderness journey because He was teaching them that man lives not by earthly bread, but by His word:
1 “Every commandment I command you today you must be careful to do, that you may live and multiply, and go in and inherit the land the Lord swore to your fathers. 2 Now you shall remember the whole way the Lord your God led you in the desert, to deal harshly with you and test you, to know what was in your heart, whether you would keep His commandments or not. 3 So He dealt harshly with you and weakened you with hunger, and fed you with manna, which your fathers did not know, that He might make you know that man shall not live by bread alone, but by every word proceeding from the mouth of God man shall live. 4 Your garments did not wear out on you, nor did your feet become callused these forty years. 5 You should know in your heart that as a man chastens his son, so the Lord your God chastens you. 6 Therefore, you shall keep the commandments of the Lord your God to walk in His ways and to fear Him.
(Deuteronomy 8:1-6 OSB)
Earthly bread sustains us because GOD created this law of nature in the beginning. Ultimately, all sustenance comes from GOD. All energy is derived from GOD. He is the only eternal energy source and the root of all life.
It is critical for us to have faith, not in our ability to provide bread for ourselves, but that GOD loves us enough to not let us go without that which we need.
In other words, we must trust, not that the bread will sustain us, but that GOD will provide the bread we need.
This Principle has messianic implications as well, as we will see in future Principles. For now, though, we will note that Jesus rebuked Satan for tempting Jesus to create His own bread when He was hungry:
1 Then Jesus was led by the Spirit into the wilderness to be tempted by the devil. 2 After fasting forty days and forty nights, he was hungry. 3 The tempter came to him and said, “If you are the Son of God, tell these stones to become bread.”
4 Jesus answered, “It is written: ‘Man shall not live on bread alone, but on every word that comes from the mouth of God.’”
(Matthew 4:1-4 NIV)
Trust in the One who gives life.