The 25-hour fast that begins on Tuesday night has put Magen David Adom on alert to cope with people who faint or feel unwell, women going into labor, car accidents and youngsters who take to the near-empty streets on wheeled objects.This year, a variety of senior rabbis have pleaded with parents to keep their children away from electric bikes during the fast, not only because riding electric vehicles is forbidden by Jewish law on the holiest day of the calendar but because unsupervised riding can be very dangerous.Every Yom Kippur, thousands of people need help from Magen David Adom. All ambulances, mobile intensive-care units, paramedics and medics have been put on alert. Some of the staffers and volunteers will be available at synagogues with synagogues with electronic defibrillators.Two MDA helicopters will be ready in the North and the South to cope with emergencies.Shira Nehushtan, a clinical dietitian at Ziv Medical Center in Safed, recommends that heavy coffee drinkers who want to fast on Yom Kippur should already be reducing their intake now to reduce their risk of headaches. One should also cut down on the amount of tea and cola, as well as carbonated drinks, that you consume and drink instead at least 10 to 12 glasses of water. On Tuesday, eat small, frequent meals rather than waiting only for the main meal before the fast.For the main meal, whole-grain pasta, bread, rice and other complex carbohydrates are best because they the leave you feeling fuller over many hours.Do not consume salty, very sweet or spicy food or carbonated drinks that will fill the stomach with gas. Eat complex carbohydrates, vegetables and protein before the fast, which begins (in Jerusalem) on Tuesday at 5:36 p.m. and ends at 6:46 p.m. Those who take medications for chronic disease, nursing mothers and others should consult their doctors about fasting. End the fast with herbal tea and a piece of pound cake or cookies that are not too sweet.Later, eat a meal that is not very heavy. Eating a lot of sugar after the fast, said Nehushtan, causes the release of a lot of insulin that makes one very hungry.