Adjust eating habits early. If you smoke or drink a lot of coffee, cut back a few weeks ahead of time instead of going cold turkey for the fast. You'll have fewer headaches and fewer cravings for fatty and sugary foods.
Fill up on foods that digest slowly, such as barley, wheat and lentils, before a fast. These foods will take about eight hours for your body to absorb. Refined sugars and white flour leave you feeling hungry sooner. Some fasters glug Gatorade to keep their salts up. After fasting, don't fill your shrunken stomach with fatty foods - fruit, nuts and liquids are recommended.
Keep your schedule
During a prolonged fast such as Ramadan, disrupt your daily routine as little as possible. Plan meals ahead of time, get lots of sleep and exercise lightly in the evenings (15 or 20 minutes of walking), if you feel you can manage it.
Gerald Filson from the Baha'i Community of Canada has been observing his faith's fast for 40 years. He says it's really not that difficult to keep within the limits: 19 days of eating only before and after sunset. "It's amazing. I can't go on a diet the rest of the year because I can't turn away a piece of pie. But when it's your spiritual obligation, you don't notice it at all."
The placebo effect
Torontonian Ellie Adler and her family have been doing the 25-hour fast for Yom Kippur for as long as she can remember. They have a prefast meal designed to stave off hunger. "Every year, my parents cook sweet potatoes the night before. They think it sticks in your stomach longer." Ms. Adler adds that, "it's probably just psychological," but the placebo effect does help.
Some fasters interpret a restriction on the consumption of everything, even toothpaste. Talk to your doctor and dentist about what type of fasting is within your limits.