Don't fast on Shabbat (except Yom Kippur!) past halachic midday:     

• If you will not finish shacharit before halachic midday, you should eat or drink earlier in the day, even before you begin shacharit—water can be sufficient for this purpose.
• If you will finish shacharit but not musaf by halachic midday:

• Finish shacharit,
• Make kiddush,
• Eat some mezonot, and then
• Return to say musaf.

As on Shabbat, don't fast on Jewish festivals (except Yom Kippur!) past halachic midday.

• If you will not finish shacharit before halachic midday, you should eat or drink earlier in the day, even before you begin shacharit—water can be sufficient for this purpose.
• If you will finish shacharit, but not musaf, by halachic midday:
  • Finish shacharit,
  • Make kiddush,
  • Eat some mezonot, and then
  • Return to say musaf.

Three Shabbat Meals
We are required to eat three Shabbat meals, as a rabbinic (d'rabanan) enactment to enjoy Shabbat (oneg Shabbat). The first Shabbat meal must be at night and the remaining two must be during the day (the third meal must be eaten after halachic midday). Friday night dinner and the first meal on Saturday are preceded by kiddush. For the first two Shabbat meals, say ha'motzi over two complete loaves of bread, each of which is at least 1.3 fl. oz. in volume. For the third meal, the ideal is to use two complete loaves of bread, but the requirement of eating the third meal can also be fulfilled by eating any food other than salt or water.

Source of Saying Shabbat Kiddush

• Saying kiddush on Shabbat night is a commandment from the Torah (d'oraita).
• Saying kiddush on Saturday morning is a rabbinical (d'rabanan) enactment.

Note If you did not say Friday night kiddush, you must say that version of kiddush on Shabbat morning and it is then a requirement from the Torah (d'oraita). Do not begin with va'yechulu; instead, begin with borei pri ha'gafen and say the second blessing of kiddush.

Source of Kiddush Location
Saying kiddush at the place where you will eat your meal is a rabbinical (d'rabanan) enactment.

Shabbat Kiddush-Meal Quantities: Evening

• For evening kiddush, a minimum of 4 fl. oz. (119 ml) of wine must be blessed on and at least half must be drunk.
• For the evening meal, as on Shabbat lunch and all required Jewish festival meals, a minimum of 1.9 fl. oz. of bread must be eaten within four minutes.

Shabbat Kiddush-Meal Quantities: First Meal on Saturday
Shabbat day first meal has two separate eating requirements.  They may be combined (say/hear kiddush and start the main meal right away) but are often done separately (say/hear kiddush and then eat some mezonot; the main meal is eaten later in the day).
Note Since eating and drinking requirements on all morning kiddushes (both Shabbat and Jewish festivals) are d'rabanan, the required beverage amount for morning kiddush is only 3.3 fl. oz. (99 ml) instead of the d'oraita 4 fl. oz. (119 ml), which is required for kiddushes for Shabbat evening.
1) Morning kiddush requires a halachically legal “meal” with these elements:
      a) Blessing on a minimum of 3.3 fl. oz. (99 ml) of wine (or other beverage),
      b) Someone's drinking at least 2 fl. oz. of the beverage, followed by
      c) Eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of some type of mezonot (or bread) within four minutes.
Note If you drink at least 3.3 fl. oz. (99 ml) of wine within 30 seconds, you do not need to eat mezonot.
Note You do not need to drink the wine or other kiddush beverage to fulfill “establishing a meal.” You may hear kiddush and then simply eat the required amount of bread or mezonot. This applies to Shabbat or Jewish festivals, evening or morning.
The kiddush “meal” does not have to satiate.
Note If you have not fulfilled the requirements for kiddush, you may not eat other foods, such as fruit or fish at a kiddush.

2) The real meal (kovei'a se'uda) of Shabbat lunch requires eating at least 1.9 fl. oz. (56 ml) of bread (or matza during Passover!) within four minutes. It should include enough food to satiate.
Note You can simultaneously fulfill the requirement to “establish a meal” and to “eat a meal” by eating one (the same) piece of bread.
For details on fulfilling the first two meals' requirements, see Shabbat: Kiddush.

Shabbat: Eating a Meal Requirement: Third Meal
For details on fulfilling the third meal's requirements, see Shabbat: Third Meal (Se'uda Shlishit).

In addition to prayer obligations (see Women: Minimal Prayer), women and girls 12 years old and up are required to keep these time-dependent positive commandments, among others:

• Candle-lighting for Chanuka (see Chanuka: Candles: Who Should Light )
• Candle-lighting for Shabbat, Jewish festivals, Rosh Hashana, and Yom Kippur.
• Havdala (say or hear) after Shabbat, Jewish festivals, Rosh Hashana, and Yom Kippur.
• Kiddush (say or hear) on the first night (or first two nights outside Eretz Yisrael) of every Jewish festival, and also the next morning.
• Passover (all commandments, including eating matza at the Passover seder).
  Note Because she must eat matza, she must therefore say birkat ha'mazon afterward (so if a woman omits ya'ale v'yavo in birkat ha'mazon at the seder, she must repeat birkat ha'mazon!).
• Megila on Purim.
• Shabbat (For why women must keep time-dependent, positive commandments on Shabbat, see Introduction to Shabbat )
• Shofar on Rosh Hashana.
  Note Jewish women universally accepted upon themselves to hear shofar on Rosh Hashana, but they only need to hear 30 blasts.
• Hearing the reading of Parashat Zachor.

If you fly through Shabbat (permitted for business only), you must keep even Shabbat d'rabanan while flying over the area of the earth that is in Shabbat.
If you fly east (such as from Asia to the US, across the Pacific) after Shabbat is over, you will re-enter Shabbat and may not do melacha on the airplane. Say the Shabbat prayers and kiddush at the appropriate local time where you are flying.
 

The fifth cup of wine at seder, for Eliyahu (Elijah) the prophet, symbolizes v'heiveiti--“I will bring them.”
Reason In the future, everyone will drink five cups of seder wine. (Some say the term v'heiveiti is not part of the redemption and some say it is a stage that has not happened yet.)
The cup of Eliyahu (which is not intended to be drunk by Eliyahu) should be used for kiddush the next morning. Various customs dictate when to fill Eliyahu's cup; it may be filled anytime from the beginning of the seder.

Shabbat was the goal of Creation. Just as God completed the world's creation on the sixth day and ceased His work on the seventh, so Jews are supposed to imitate God and not do any creative work on the seventh day. Everything we need for living through Shabbat must be prepared ahead so that we do not do any creative activities on Shabbat.
Our observance of Shabbat thus testifies that God created the world. In the Shabbat kiddush, we mention the Exodus from Egypt, too, to testify to the world that God is continuously involved in our lives.
By ceasing our normal efforts to dominate the physical world, we can appreciate the spiritual aspects of our existence.
On Shabbat, all observant (shomer Shabbat) Jews receive an extra “soul.”

Zachor and Shamor

Remember (Zachor) the Sabbath day to make it holy—Exodus/Shmot 20:8
Observe (Shamor) the Sabbath day to make it holy—Deuteronomy/Devarim 5:12
Shabbat has two dimensions:

• Zachor  “Remember,” encompassing positive (“to do”) commandments, and
• Shamor  “Observe,” encompassing negative (“refrain from”) commandments.

Zachor:  Positive Shabbat Commandments
What Are Positive Shabbat Commandments
Positive Shabbat commandments include:

• Lighting candles,
• Making kiddush evening and morning,
• Making havdala,
• Honoring Shabbat (Kivod Shabbat), and
• Enjoying Shabbat (Oneg Shabbat), including eating three meals on Shabbat.

Honoring Shabbat: Special Food and Clothes
Honoring Shabbat includes eating tasty food and wearing nice clothes.

Shamor: Negative Shabbat Commandments
Shabbat Laws from the Torah (Shabbat D'Oraita)
What Are Melachot
On the Jewish day of rest, we refrain from 39 creative activities (melachot) that had been used to build the Tabernacle in the wilderness. These 39 melachot, prohibited by the Torah, are listed in the mishna of Shabbat and in later halacha books.

The word melacha is frequently mistranslated as “work,” but work has nothing to do with the Jewish concept of melacha. Some melachot are physically strenuous (plowing, grinding wheat, skinning an animal) and some are easy to do (drawing, baking). The defining point is whether the activity is one of the 39 creative, value-adding labors. Emptying your pockets before leaving an eruv (so you are not “carrying”) may seem confusing to someone who thinks that resting on Shabbat means refraining only from hard physical labor!

What Are Toldot
Toldot are variations of the 39 melachot. These types of melacha are also prohibited by the Torah.

Intention and Other Considerations
Most Torah (d'oraita) prohibitions of melacha on Shabbat are for cases in which you:
            1) Intend a permanent change.
                Often, actions that may be forbidden when they cause permanent change, will
                be permissible by Torah law if the result is only temporary. Or
            2) Intend or act for a specific purpose.
                Random or unintended actions are generally not prohibited by Torah law.
                (However, actions that are not prohibited by the Torah, may be prohibited
                by Chazal.)

Whether you may benefit from a melacha done on Shabbat depends on intention:

• A Jew who intentionally does a melacha on Shabbat may never benefit from that melacha.

            Note Any other Jew may benefit from that melacha as soon as Shabbat is over.

• A Jew who does melacha on Shabbat by mistake (shogeg) may benefit from that melacha immediately after Shabbat ends.

In order to violate a prohibited melacha d'oraita, the melacha must be done as follows. If any of these do not apply, then the melacha is forbidden d'rabanan but not d'oraita:

• K'darko--The action must be done in a normal way.
• Tzorech tikun—The action must be done for a constructive purpose.
• Tzricha l'gufa--You must need the normal result of that action.
• Asiya b'yachid—The action must be done by one individual (if commonly done by just one person).
• Mit'aseik--You must realize that you are doing a melacha.

 
Shabbat Laws from Chazal (Shabbat D'Rabanan)
Chazal instituted additional restrictions, such as:

• Activities that might lead directly to violating a Torah prohibition.
• Use of items not designated for Shabbat use (muktza). For a good explanation of muktza from the TorahTots website, please click here.
• Activities that might lead one to think that a prohibited activity is permissible (mar'it ayin--the appearance of the eye).
• Activities that are not appropriate for Shabbat, even though they are technically permissible according to the Torah (“uvda d'chol”).
• Tircha--Exerting a physical effort to accomplish a result that is not required for Shabbat.

Enjoying Shabbat/Oneg Shabbat
Chazal instituted laws to engender a positive Shabbat atmosphere and experience.  Beyond the actual halachot of shamor and zachor, we have a concept of enjoying Shabbat (oneg Shabbat)—of enhancing our experience of Shabbat by doing whatever each person finds to be enjoyable and relaxing--as long as it is neither destructive nor violates the laws of Shabbat. The criteria are subjective. To fulfill the idea of honoring Shabbat, do things you would not do just for yourself if it were not Shabbat. Take essential life activities such as eating and sleeping and do them more and better and make them especially enjoyable.

Meals as Oneg
On Shabbat, we eat better foods and more types of food than we would normally do on weekdays.
The main idea behind meals for Shabbat is enjoyment (oneg; by contrast, the main idea for Jewish festivals is joy--simcha), so on Shabbat you should eat bread and either fish, poultry, or meat (but only if you enjoy them).
In order to have a special appetite for our Shabbat evening meal, we don't eat a full meal with bread on Friday afternoon.

Special Shabbat Songs (Zmirot)
Special songs (zmirot) are sung at the various Shabbat meals. Some zmirot have an aspect of prayer to them.

Studying Torah
Studying Torah on Shabbat is another way of increasing our spiritual experience. It honors the Shabbat and should bring about enjoyment of Shabbat.

Shabbat and Muktza
For information on Shabbat and muktza, see section below, Shabbat: Muktza.

Weekday Talk
Don't talk about subjects that are forbidden to do on Shabbat (weekday subjects); for example, don't talk about what you will do after Shabbat is over. There is no prohibition about discussing actions from the past as long as no planning is discussed.

Almost all mitzvot may be enhanced by:

• Making them beautiful (hidur mitzva), or
• Observing non-required stringencies (mehadrin).

Although women and girls are generally exempt from time-dependent positive commandments (mitzvot), they may do some mitzvot for which they are not obligated and it is considered to be virtuous behavior for which they will get a reward. They may say the blessings before each mitzva.

1. These are voluntary mitzvot that women may do:

• Lulav

• Sukka

• Saying the full shema.

2. Women and girls MAY NOT  wear tefilin.

 

3. Women traditionally do not:

• Say tachanun. 

• Wear talit or tzitzit (talit katan).

• Study gemara.

• Say kiddush levana or birkat ha'chama.

But these are not forbidden.

 

Your fore-blessing covers all other same-category foods that you will eat at the same time (same sitting), if:

1. They are in front of you when you say the blessing, OR
2. You intend your blessing to cover all other same-category foods that you own and will eat at the same sitting--even if they are not in front of you when you make the blessing.
   Note You do not need to state your intention out loud, just think it.  If you usually have this intention but you forgot on an occasion, you do not need to say new blessings on the subsequent foods of that type that you already own.

• You say she'hakol over two kinds of she'hakol foods on your table.  The blessing also covers a third she'hakol food in your refrigerator and a fourth in your pantry that you know you own.
• You say she'hakol and are eating an omelette when a visitor brings you a gift of chocolates: you must say a new she'hakol]blessing before eating the chocolates.
  Note Anytime your spouse is serving you food, it is assumed that your initial fore-blessings will cover all food that you will eat.

• Guest at Someone's Home
  Whenever you are a guest at someone else's house, it is assumed that whatever foods you will eat, will be covered by your initial fore-blessing as long as they are in the same category.
• Attendee at Kiddush or Wedding
  If you say she'hakol over fish at a kiddush or wedding, the blessing covers all she'hakol foods in the room.
• Diner in Restaurant
  If you have made an order in a restaurant, all ordered foods will be covered by your first fore-blessing(s). However, if you later order more food, even if the fore-blessings are the same, you must still say a new fore-blessing.

Who Is a Mourner

A mourner is defined in halacha as someone mourning during the 12-month mourning period for parents or the 30-day mourning period for the other five relatives (spouse, brother, sister, son, daughter). After 30 days, one is no longer a mourner for anyone but one's parents.

Mourners' Restrictions

If the mourner goes about business as usual, it may show he or she doesn't care about the close relative who died. The mourner should ideally not want to do these things. The mourner honors the dead person by refraining from pampering him/herself and refraining from going about his or her life as usual.

Public Meals

A mourner may not attend a public meal for any purpose. For example, if the mourner attends a lecture or Torah class at which food is being served, he or she may not eat the food. This only applies to sit-down meals; snacking is permitted.

Siyum/Brit/Bar Mitzva

After 30 days after a parent's burial, a mourner may:

• Attend a siyum or bar mitzva and eat there.
• Attend a brit but not eat there.

Note If there is music (live or recorded), the mourner must leave.

Weddings

A mourner may not eat at a wedding and may not even be in the wedding hall after the ceremony took. The mourner may also not hear the music at a wedding.

Exceptions

• If the mourner is the parent of someone getting married, the mourner can fully participate in the wedding.
• If the mourner is the bride or groom, he or she must normally wait to get married until after shloshim/30 days.

Note If it is after shiva, but still during shloshim, consult a rabbi.

Kiddush and Shabbat or Festival Meals

A mourner may not publicly (noticeably) mourn on Shabbat or festivals so he or she may attend Shabbat or festival meals and kiddushes if he or she would be expected to attend. If the mourner always or routinely invites some person or a lot of different people on Shabbat or festivals, it is still permitted. If the mourner does not routinely invite some person or a lot of different people to a Shabbat or festival meal, then he or she may not, for his or her own enjoyment, invite guests for meals. However, the mourner is permitted to do so for other purposes (for the benefit of the invited person or people), such as kiruv or hachnasat orchim. There is no limit to how many guests the mourner may host.

The mourner may attend or host a sheva brachot in his/her home.

A mourner should not be invited to meals, even for Shabbat or festivals; but if he/she was invited, he/she may go.

Holidays

A mourner does eat at a Purim or Jewish festival seuda, since there is no mourning on Purim nor on any festival (except Chanuka).

Jewish Festivals are listed in the Torah and are of two types: 

1. Three pilgrimage festivals (shalosh regalim):

• Passover,
• Shavuot, and
• Sukkot (including Shimini Atzeret).

These festivals were celebrated in ancient times by "appearing before God"--by bringing offerings to the Tabernacle or Temple.

2. High Holidays: 

• The Jewish New Year (Rosh Hashana—“Yom Teru'a” in the Torah), and the
• Day of Atonement (Yom Kippur).

 
Duration
Jewish holidays that were originally one day are now observed as follows:

• Rosh Hashana--2 days.
• Yom Kippur--1 day.
• Shavuot--1 day in Eretz Yisrael or 2 days elsewhere.
• Passover has festival days at the beginning and end of the holiday and intermediary days of lesser holiness, which are called chol ha'moed. In Eretz Yisrael, Passover lasts for 7 days in total and the first and last days are festival days. Outside of Eretz Yisrael, Passover lasts 8 days and has two festival days at the beginning and two at the end.
• Sukkot has festival days at the beginning and at the end and intermediary days of lesser holiness, which are called chol ha'moed. In Eretz Yisrael, Sukkot lasts for 8 days and the first and last days are festival days (the last day is Shimini Atzeret). Outside of Eretz Yisrael, Sukkot lasts for 9 days and the first two days and last days are festival days (the 8th day is Shimini Atzeret and the 9th day is Simchat Torah).

Character
Each holiday contributes its own character to Jewish life (Passover--the theme of freedom; Yom Kippur brings atonement, etc.). 

Celebrating
How to celebrate these holidays is detailed in our Oral Law and halacha books. Jewish festivals as practiced today are similar in holiness to Shabbat. As with Shabbat, the Jewish festival has candle lighting, kiddush at two meals, and havdala.   We eat our best food and wear our best clothing on Jewish festivals (we eat our next-best food and wear our next-best clothing on Shabbat!).
The main idea behind eating meals on Jewish festivals is joy (simcha), so you should drink wine and eat meat (only if you enjoy wine and meat).  There is no third meal on Jewish festivals since people used to eat two meals each day (adding a third meal on Shabbat was for enjoyment/oneg).
 
Melachot
Any activities or actions permitted on Shabbat are also permitted on the Jewish festivals. Actions that are forbidden on Shabbat are generally also forbidden on Jewish festivals, but there are some leniencies (only if the actions are needed for that festival day).
Examples

• Lighting from an existing flame,
• Cooking and baking for the Jewish festival day, and
• Carrying outside the eruv (hotza'a--transferring objects between domains).

 
Grama
Grama (indirectly causing an action) is permitted on Jewish festivals (but not on Shabbat). For example, you may advance or delay a timer that will make a light go on or off in the future (the timer must already be plugged in and operating from before sunset of the festival day).
Note For an action to be considered indirect based on time, there must be at least 2.5 seconds after the first action is done before the resulting action begins to happen.

Psik Reisha Dla Neicha Lei
Psik reisha dla neicha lei is forbidden on Jewish festivals, just as it is on Shabbat.

D'oraita Restrictions
D'oraita restrictions apply world-wide to:

• First and seventh days of Passover,
• First and eighth days of Sukkot,
• First day of Shavuot,
• Yom Kippur,
• First day of Rosh Hashana.

Note The same restrictions apply to all other Jewish festival days but are rabbinical.
 
Women
In general, women are not required to perform the positive, time-dependent commandments. Women and girls are not required to eat any Jewish festival meals except the Passover seder meal (but they are not allowed to fast on those days).

“Be holy because I, the Lord your God, am holy.” Leviticus/Vayikra 19:2
 
Halacha ("The Way To Go" or "Way to Walk") guides proper Jewish behavior in all aspects of life, each day of our lives--not just in civil laws or court situations. Halacha teaches us how to behave with our families, relatives, and strangers as well as how to fulfill our religious requirements between ourselves and God.

To fulfill our role as a holy people, we imitate God's actions. Examples are visiting the sick, welcoming guests, giving charity, refraining from creative activity on Shabbat, and promoting peace between husband and wife (shalom bayit).

The true reason for following halacha is because God commanded us to do so.  We observe halacha to please our Creator and to become spiritually close to Him by doing His will and imitating His actions.

Like the word for the whole body of Jewish "laws," each rule of how to act is called a halacha (plural, halachot).

Where Do Halachot Come From?

Although you will find halachot on this site that were born only a few days or a few decades ago, the body of halacha has been around since before creation.  "God looked into the Torah and created the world," says the Zohar, and so we find the Patriarchs followed halacha even before that great law book, the Torah, was given on Mount Sinai four centuries later.
 
Many halachot are specified in the Written Torah (Jewish Bible). These halachot correspond to fuller and more detailed halachot given orally (Oral Torah) to Moses on Mount Sinai to explain the Written Torah that he received at the same time. Many halachot could not be understood from the Written Torah without the Oral Law (for example, what should be written on a mezuza scroll?) and many common practices such as making kiddush or what tefilin should look like are to be found nowhere in the Written Torah.
 
Since the Torah applies to all generations, the Torah specifies that there be wise and learned people to decide how to apply halacha to the situations of the day.  Halachot can be found in sourcebooks such as the Mishna, Gemara, their commentaries, Shulchan Aruch, Mishna Berura, and responsa (questions and answers originally sent by letter and now, occasionally, by email or SMS!) of later rabbis.
 
Sometimes a custom becomes a halacha, sometimes not.  For example, the original halacha for tzitzit was that a Jewish man who wears a four-cornered garment must have tzitziyot on each corner.  The custom, which has become universally accepted and now has the force of halacha, is that Jewish men wear a four-cornered garment in order to be able to fulfill the commandment of wearing tzitziyot.  An example of a custom that did not become a halacha is that some men and boys wear their tzitziyot outside of their shirts and pants.

Levels of Halachot

In halacha, there are three levels of what to follow or observe. They are differentiated on this website by the following terms: 

• “Must”:  Halachot that are generally non-negotiable except in extreme situations;
• “Should”:  Customs that have been accepted by the entire Jewish world (or major segments of it) and that may be overridden when necessary, sometimes even if not extreme circumstances; and
• “Non-Binding Custom”:  Customs that are not universally followed and that do not need to be followed except by people who have the tradition to do so.

To say any after-blessing/bracha achrona (al ha'michya, al ha'gafen, al ha'eitz, borei nefashot, or birkat ha'mazon), you must:

• Eat at least the minimum volume (1.3 fl. oz.--39 ml, or 1/6 cup) of solid food within four minutes, or
• Drink at least 3.3 fl. oz. (99 ml) of liquid within 30 seconds.

If Did Not Eat Minimum

Do not say bracha achrona if you did not eat 1.3 fl. oz. (39 ml) within four minutes.

If Did Not Drink Minimum

Do not say bracha achrona if you did not drink 3.3 fl. oz. (99 ml) of any potable liquid within 30 seconds. Note You may not combine the volume of solid food to liquid food or liquid food to solid food that you ate and drank in order to make the minimum volume for an after-blessing.

If Did Not Eat or Drink Minimum

Size: How To Calculate

Ounces: Weight or Volume

The minimum quantity for saying after-blessings is based on volume, not weight. If you eat a pack of pretzels whose volume is 1.3 fl. oz., even though the label says it only weighs 0.5 oz., you would say an after-blessing of al ha'michya.

Figuring Volume

Figuring Volume: Non-Mezonot Foods

You may not include the volume of fish or meat or other foods eaten together with bread or matza in order to reach a total volume of 1 fl. oz., which is required for saying the after-blessing of birkat ha'mazon. However, you may combine the volumes in order to say borei nefashot.

Figuring Volume: Unswallowed Pits/Seeds

When eating foods with seeds or pits (olives, pomegranates, etc.), do not include unswallowed seeds or pits to reach the 1.3 fl. oz. (39 ml, or 1/6 cup) minimum volume needed to say an after-blessing. You may include only what you have swallowed.

D'Oraita Cases

For d'oraita cases (halachot from the Torah), such as eating matza at seder or drinking wine for kiddush, we use a more stringent minimum measure:

• Eat at least 1.9 fl. oz. (56 ml) of solid food within four minutes, or
• Drink at least 4 fl. oz. (119 ml) of liquid within 30 seconds.

Timing

When To Start Counting

You may start counting the period of four minutes (for eating at least 1.3 fl. oz.) or 30 seconds (for drinking at least 3.3 fl. oz.) any time after the fore-blessing as long as it is continuous from when you first swallow until you have swallowed the minimum amount.

Introduction to Fast Days
The purpose of Jewish fast days is to make us reflect on our behavior and improve it by:

• Eliminating negative actions and thoughts, and
• Taking more care in our observance of the commandments.

God told the Jewish people on many occasions that He did not want their pointless sacrifices or fast days but rather wanted the Jews to improve their behavior. If people fast but still have reprehensible behavior, the people have missed the point and purpose of bringing sacrifices and having fast days.
All fast days may be circumvented for health reasons. Consult a rabbi.
Fast days come in several varieties:

• Major fast days: Yom Kippur and the Ninth of Av (Tish'a B'Av). 
• Minor fast days: There are four minor fast days; see below.
• Fast for First-Born
• Individual Fasts

The Major Fasts
Yom Kippur and the Ninth of Av begin before sunset and are both slightly longer than 24 hours. Yom Kippur is a festive day while, on the Ninth of Av, Jews mourn for the destruction of both Jerusalem Temples (the first was destroyed by Babylonians; the second, by the Romans). On both fasts, it is forbidden to:

• Eat or drink.
• Wear leather shoes (but you may wear any other clothing made of leather).
• Bathe (or even to wash anything more than fingers; you may not use a deodorant--not even a spray type--since it is similar to washing).
• Have marital relations.
• Use cosmetics or body scents.

The Minor Fasts
The four minor fasts begin 72 minutes before local sunrise. They technically end at dark but functionally end after ma'ariv (and for the Fast of Esther, after hearing the megila). Unlike most times in the Jewish calendar, this 72 minutes is normal time and NOT based on the current length of the day (sha'a zmanit):

• Fast of Esther (Ta'anit Esther): Day preceding Purim (or sometimes earlier).
• Fast of Gedalia (Tzom Gedalia): Usually the day after Rosh Hashana.
• Tenth of Tevet (Asara b' Tevet):
• Seventeenth of Tamuz (Shiv'asar b'Tamuz): Beginning of the Three Weeks of semi-mourning beforeTish'a b'Av.

On all fast days, eating and drinking are forbidden. The Tenth of Tevet and the Seventeenth of Tamuz additionally have the same restrictions as the Nine Days. So you may wash or bathe on the Fast of Esther and on Tzom Gedalia but not on the Tenth of Tevet and the Seventeenth of Tamuz. (See Nine Days: Restrictions).
Note On a fast day that has been delayed for Shabbat, there may be leniencies for:

• The mohel, sandak, and father of a baby getting a brit mila to eat after mincha.
• Pregnant or nursing women (this leniency applies to eating throughout the day).

Fast for First Born
Fast for first-born males 13 years old and older, on the day before Passover. This includes first-born cohanim and Levites (levi'im). The fast begins 72 normal minutes before sunrise and ends with kiddush at the seder. However, the widespread custom is to attend a siyum on the day before the first seder so that the first-born men do not need to fast on that day.
 
Personal Fasts
Fast by a groom and bride on their wedding day is an example of personal fasts. This fast begins 72 normal minutes before sunrise and ends with drinking wine under the chuppa.