From what I've been told, there are certain exemptions to the requirement to fast during Ramadan. If you've had a baby in the past 40 days, you're allowed to eat and drink. If you're traveling, you get to eat and drink. If you're ill, you're allowed food and medicine. If you're menstruating, you're unclean anyway, so fasting won't count - might as well eat and drink. If you vomit, you're unclean, plus presumably ill, so go ahead and replenish your body.
(NB: Yes, medicine is also forbidden during daylight hours of Ramadan. Nothing can cross your lips and be consumed. I wonder how modern Muslim scholars address the question of IV medication?)
In each of these cases, though, the exemptee is expected to "make up" the days of fasting, sometime later in the year. Many do it immediately after the holy month ends, others wait and make up their days later on. Around here, people refer to the days of fasting that they owe as "credit" (pronounced in the French manner, cray-dee), as though they've taken out a loan and must pay it back.
There's a certain amount of gray area as to the application of these exemptions. Just *how* sick do you have to be in order to be allowed to eat? At death's door? Bed-ridden? Mildly uncomfortable? A little sniffly? And how far do you have to travel to be considered a "traveler"? Here in Morocco, almost no one recognized the "traveler" exemption except for long voyages on foot. My friends who hiked Toubkal during the first days of Ramadan were universarlly encouraged to eat and drink. Folks riding around on buses and planes aren't considered to be exerting themselves overmuch, and therefore are still expected to fast. (I remember last year, sharing a bus seat with a young woman who whispered to me that she had the "problem of women" - her phrase - and therefore was eligible to eat. Even though we were riding for six hours on a bus, she didn't feel license as a traveler to get to eat or drink, so she contrived to hide her snacking from other passengers, through careful use of her headscarf and by turning in her seat to face me and the window.)
Here in Morocco, fasting is at least as much a cultural phenomenon as a religious one. Everything changes, from restaurant and business hours to the foods available in souq to TV programming. Everyone is expected to stay up most (if not all) of the night and sleep for most of the day. The Post Office in Berberville maintains its usual hours of operation, but everything else in town - shops, pharmacies, even the police station! - closes down for most of the day and opens for most of the night. For a month, the country becomes...nocturnal.