are there different types of fasts...
is there a daniel fast...
is fasting biblical...
Susie, these are good questions. Let me answer the last question first. Yes, fasting is Biblical, as the examples below demonstrate. It is often mentioned incidentally in recounting events that occurred, and sometimes it is mentioned as a part of prescription for seeking enlightenment from God.
EXAMPLES OF VOLUNTARY FASTS--for spiritual reasons.
Psa 35:13 But as for me, when they were sick, my clothing [was] sackcloth: I humbled my soul with fasting; and my prayer returned into mine own bosom.
Mark 9:29 And he said unto them, This kind can come forth by nothing, but by prayer and fasting.
Luke 2:37 And she [was] a widow of about fourscore and four years, which departed not from the temple, but served [God] with fastings and prayers night and day.
Luke 5:35 But the days will come, when the bridegroom shall be taken away from them, and then shall they fast in those days.
Acts 10:30 And Cornelius said, Four days ago I was fasting until this hour; and at the ninth hour I prayed in my house, and, behold, a man stood before me in bright clothing,
Acts 13:2 As they ministered to the Lord, and fasted, the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them.
Acts 13:3 And when they had fasted and prayed, and laid [their] hands on them, they sent [them] away.
Acts 14:23 And when they had ordained them elders in every church, and had prayed with fasting, they commended them to the Lord, on whom they believed.
1Cor 7:5 Defraud ye not one the other, except [it be] with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency.
EXAMPLES OF INVOLUNTARY FASTS--when the person didn't choose to go without food.
Mark 8:3 And if I send them away fasting to their own houses, they will faint by the way: for divers of them came from far.
Acts 27:33 And while the day was coming on, Paul besought [them] all to take meat, saying, This day is the fourteenth day that ye have tarried and continued fasting, having taken nothing.
2Cor 6:5 In stripes, in imprisonments, in tumults, in labours, in watchings, in fastings;
2Cor 11:27 In weariness and painfulness, in watchings often, in hunger and thirst, in fastings often, in cold and nakedness.
Since you are asking this on a Seventh-day Adventist section of "All Experts," I will add some statements made by Adventist pioneer, Ellen G. White, as she gives practical applications for fasting:
"Intemperate eating is often the cause of sickness, and what nature most needs is to be relieved of the undue burden that has been placed upon her. In many cases of sickness, the very best remedy is for the patient to fast for a meal or two, that the overworked organs of digestion may have an opportunity to rest. A fruit diet for a few days has often brought great relief to brain workers. Many times a short period of entire abstinence from food, followed by simple, moderate eating, has led to recovery through nature's own recuperative effort. An abstemious diet for a month or two would convince many sufferers that the path of self-denial is the path to health" (The Ministry of Healing, p. 235).
Mrs. White also mentions how a short fast can be beneficial in resetting the taste buds to enjoy simple, wholesome foods when one is used to spicy, rich foods. (See Spiritual Gifts, vol. 4, pp. 130, 131, in Counsels on Diet and Foods, p. 190, par. 2). Then she points to a use of fasting to clear the mind in prayer and a fast that a person can sustain throughout life.
"For certain things, fasting and prayer are recommended and appropriate. In the hand of God they are a means of cleansing the heart and promoting a receptive frame of mind. We obtain answers to our prayers because we humble our souls before God" (Counsels on Diet and Foods, p. 187, par. 6).
"The true fasting which should be recommended to all, is abstinence from every stimulating kind of food, and the proper use of wholesome, simple food, which God has provided in abundance. Men need to think less about what they shall eat and drink, of temporal food, and much more in regard to the food from heaven, that will give tone and vitality to the whole religious experience" (Letter 73, 1896, in Counsels on Diet and Foods, p. 90, par. 1).
The last quotation reminds one of Isaiah's counsel from the LORD about the spiritual fast that God desires--"letting go of things" not just for show (as the Pharisees engaged in fasting):
Isa 58:3 Wherefore have we fasted, [say they], and thou seest not? [wherefore] have we afflicted our soul, and thou takest no knowledge? Behold, in the day of your fast ye find pleasure, and exact all your labours.
4 Behold, ye fast for strife and debate, and to smite with the fist of wickedness: ye shall not fast as [ye do this] day, to make your voice to be heard on high.
5 Is it such a fast that I have chosen? a day for a man to afflict his soul? [is it] to bow down his head as a bulrush, and to spread sackcloth and ashes [under him]? wilt thou call this a fast, and an acceptable day to the LORD?
6 [Is] not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke?
This passage explains that fasting isn't for getting God's attention. God wasn't impressed by fasting; He desired Israel's conversion with evidence of her change.
Daniel's fast, as found in Daniel 10:3, was: "I ate no pleasant bread, neither came flesh nor wine in my mouth, neither did I anoint myself at all, till three whole weeks were fulfilled." In verse 2, he had said this was because he was "mourning."
Since the practical value of fasting is generally to clear the mind, this can be accomplished by different levels of fasting. It could be simply with water. However, one could also just use fruit juices or vegetable juices, or one could limit the kinds of food one consumes, as to just fruits or the simple diet mentioned by Ellen White. How one chooses to fast depends on what purpose one has.
I hope this helps.