Blessed are You, Lord our God, King of the universe, Creator of numerous living beings and their needs, for all the things You have created with which to sustain the soul of every living being. Blessed is He who is the Life of the worlds.
All food blessings are simply a “thank you” to God for creating the food. He already blessed the food in the creation. The food itself belongs to Him, it is His creation for us thus we should thank Him for supplying it.
Psalm 24: 1 Of David, a song. The land and the fullness thereof are the Lord’s; the world and those who dwell therein.
There are actually two blessings every time we eat, one before and one after. Important to note: You do not say Amen after you say the blessing but someone who hears the blessing may say Amen. Each person should say a blessing for each person is thanking God personally for the provisions.
On Shabbat and festivals when a group is eating together the male who is sitting at the head of the table may do the Bread and Wine blessings to cover all.
The “Before Blessings”
Bread: First we wash our hands and then break off a small amount of bread, dip it in salt and say: Blessed are You, Lord our God, King of the Universe, Who brings forth bread from the earth. This covers all food eaten during the meal except dessert and wine.
Wine: Wine or grape juices have their own blessing. Blessed are You, Lord our God, King of the universe, Who creates the fruit of the vine.
Foods eaten without bread or at a meal without bread each have their own blessing before and after eating.
Mezonot: These are any foods made from grain but not bread. Pastries, pasta, cakes, crackers, cereal, and more….Blessed are you Lord our God, King of the Universe, Who creates various kinds of sustenance.
Fruits: Anything growing from tress, up from the ground. Blessed are You, Lord our God, King of the universe, who creates the fruit of the tree.
Vegetables: legumes including peanuts, melons, pineapples, bananas. Blessed are You, Lord our God, King of the universe who creates the fruit of the earth.
Shehakol: All other foods and drinks not mentioned above. Blessed are You, Lord our God, King of the universe, by Whose word all things came to be.
After Meal Blessings
Blessing for a full meal is here http://www.chabad.org/library/article_cdo/aid/135366/jewish/Grace-After-Meals-in-English.htm
Blessing after other foods are here: http://www.chabad.org/library/article_cdo/aid/135397/jewish/Blessings-After-Other-Foods.htm