In fact, that is exactly what it is like. Except it isn't a boost that my spirit has had, it is simply because my spirit has actually had some nourishment that day.
Most of you know the story from the gospels where Jesus has been in the wilderness for 40 days, and Satan comes to Him and starts to tempt Him. One of those temptations is to turn some stones into bread, and Jesus' response, according to Matthew 4:4 is, "It is written, 'MAN SHALL NOT LIVE ON BREAD ALONE, BUT ON EVERY WORD THAT PROCEEDS OUT OF THE MOUTH OF GOD.'"
Notice that He says, "It is written..." at the beginning of His response. If you go back to see where it was written, you will find it in the book of Deuteronomy. Let me quote for you here the first 3 verses from Deuteronomy 8:
All the commandments
that I am commanding you today
you shall be careful to do,
that you may live and multiply,
and go in and possess the land
which the LORD swore to give to your forefathers.
You shall remember all the way
which the LORD your God has led you
in the wilderness these forty years,
that He might humble you,
to know what was in your heart,
whether you would keep His commandments or not.
He humbled you and let you be hungry,
and fed you with manna which you did not know,
nor did your fathers know,
that He might make you understand
that man does not live by bread alone,
but man lives by everything
that proceeds out of the mouth of the LORD.
Whatever it is that you might face, whatever wilderness that you are in, you need nourishment. The world (and our own deceitful heart) is constantly trying to confuse the issue and trying to tell us what we need. Whether it be companionship, money, pleasure, vindication, a good job, obedient children, or even actual food, we are all wanting things, we are all feeling hungry. God is saying that He is going to fulfill and provide for all of those needs. He is going to bring us into the right place at the right time. He has promised so much, but sometimes, according to this passage, before we go into that promised land of fulfilled living, He wants to test us. He wants to know what is in your heart, He wants to know whether or not you will really keep his commandments.
Maybe you are in a state of hunger right now. I know that I have been before and that most likely, before I am done with this planet, I will be in that state again. But when God humbles you and leaves you hungry, or when he provides for you in a way that you would never have expected, please realize that your heart is being revealed. I know that there have been many times that God has left me hungry, and I came up lacking. But He has taught me that there is no way that I can live, absolutely no way that I can manage this life on bread (whatever that bread might be) alone. I must live on God's Word. It is my only true nourishment.
I am slightly hypoglycemic, so when I miss a regular meal I start to get shaky. But when I miss some of the bread of the Word of God, I can fall apart. I just can't figure out why I keep forgetting that.