Who is obligated to Fast
It is obligatory for the one to fast the month of Ramadan if the following conditions are met:
1- If the one is Muslim
4- The one whose body can tolerate fasting
5- Pure (exempting the menstruating and postpartum bleeding woman)
Who is permitted Islamically to break their fast
1- If one is Muslim: The first condition for one to be obligated to fast is to be Muslim. In this world, we do not request from the non – Muslim to fast; however, in the Hereafter, he will be punished for neglecting to fast, as he will be punished for his blasphemy. Rather, the obligation on the non – Muslim is to embrace Islam, then among many obligations, is to fast Ramadan.
2- Pubescent: Secondly, the Muslim must be pubescent. The child is not obligated to fast. However, it is an obligation on the guardian of the child to order him or her to fast once he or she is seven (lunar) years old, with the condition that the child's body can withstand fasting, without being harmed.
3- Sane: Also, for one to be obligated to fast, one must be of sound mind. Fasting is not obligatory on the insane person.
4- The one whos body can tolerate fasting: Fasting is not obligatory on a person whose body cannot tolerate fasting, either due to old age or severe illness. Moreover, if a person may be harmed by fasting, that is, as a result of his fasting his sickness may worsen or he may die, then fasting is prohibited for him.
The person who does not fast because of old age or an illness he is not hopeful to be cured of, does not have to make up the missed days of fasting. Instead, he pays an expiation to a poor Muslim for every day of fasting he missed. He can pay the expiation for every missed day to the same person or he can choose to pay it to different people. The expiation is a pair of average-sized hands cupped together (mudd) filled with the most common staple food of the town. In the United States, for example, the most common staple food is wheat, however in Asia, the most common staple food would be rice.
5- Pure (Tahir): Fasting is not obligatory on the menstruating woman or the woman who has her postpartum bleeding. In fact, it is unlawful for them to fast. The woman who missed days of fasting during Ramadan for these reasons has to make up each missed day.
Who is exempted from fasting and who is permitted Islamically to break their fast
The Pregnant & Breast Feeding woman: Also, the pregnant woman is allowed not to fast if she fears harm may come to her or her baby from her fasting. This includes the breastfeeding woman as well. She is allowed not to fast if she fears harm may come to her or her baby from her fasting. Both, the pregnant and nursing women, must make up every missed day of fasting. If the reason such a woman did not fast was solely the fear of harming her baby, then in addition to making up the missed days of fasting, she must pay an expiation. This expiation is a pair of average-sized hands cupped together filled with the most common staple food of the area where she lived, for each day she missed.
The Traveller: The person who is traveling a walking distance of two or more days (about 80 miles) is allowed to break their fast, provided his traveling is not sinful. This traveler is permitted to break his fast even though he may not encounter hardship during his trip, such as if he crosses this distance quickly, by plane, or comfortably, in a car or a train. The matter of traveling is not based on the hardship; rather, it has to do with the distance. This facility for the traveler was mentioned in the Qur'an. Allah سبحانه وتعالى said in Surat al-Baqarah, Verse 185:
وَمَن كَانَ مَرِيضًا أَوْ عَلَى سَفَرٍ فَعِدَّةٌ مِّنْ أَيَّامٍ أُخَرَ
which means: If one is sick or traveling, then one is allowed to break their fast and one makes up the missed days later.