They will be hungry and thirsty for an entire month, feel low on energy and even have to watch their language.

Abstaining from food and drink from sunrise to sunset isn’t required of people younger than 18 during Ramadan, the most important religious observance of the year for Muslims. But young brothers Talha and Saifullah Quadri have chosen to take on the difficult regimen of controlling human desire in the coming 30 days.

Talha, a 15-year-old student at Roosevelt High School, said, "It’s kinda hard. I have to wake up before sunrise and try to eat a lot to last you a long time. You have to refrain from doing bad things, using abusive language or a certain tone of voice, but I feel a lot better because I do a lot more good things, like helping people out when they ask, small acts of kindness. I don’t tease people as much," he added, looking at his little sister, Maria.

Saifullah, 13, will join his older brother and their parents on their Ramadan fasting regimen.

The first day of Ramadan starts with the new or crescent moon on Aug. 1 and ends Aug. 30, said professor Abdul-Karim Khan, who teaches Islamic culture and other history courses at Leeward Community College. The dates are based on the lunar Saudi ARAMCO World Calendar 2011, he said.

Ramadan not only means abstaining from food, drink and sex during the day ("Not a single drop of water can pass your throat," Khan said), it involves developing self-control, a quality people hope they can master throughout the year, Khan said. People try to read and recite more from the Quran (Islam’s holy book) and pray more regularly, even those who don’t pray the customary five times per day, he said.

"You’re supposed to keep yourself spiritually clean — no rumors, no backbiting. Don’t use foul mouth. Don’t go to places of moral laxity, like clubs. Do more at home with your families; take a vacation, go to Mecca. Be more in the company of spirituality. That’s how you see no evil, hear no evil, speak no evil," Khan said.

But if fasting makes you dehydrated or sick, don’t do it, he said, adding that pregnant women and nursing mothers should never fast.

"The idea is not to kill yourself; the idea is to worship God. And nobody is your judge; you are your own judge. If you can do it, do it. This is a very private matter. For every day you miss, you should feed a poor person," Khan said.

People usually start feeling more pronounced effects of fasting by the 15th day, he said, and try to decrease their activities and stay indoors where it is cool and quiet, especially in the warmer climates. Farmers or laborers suffer in particular with the lack of food or water, so if they are the sole providers for their families, "they have to eat so their children won’t starve. Islam takes all human needs into consideration," Khan said.

Anwar Quadri and wife Nighat, both state Department of Health educators, told sons Talha and Saifullah not to fast when they have PE (physical education) or basketball practice during Ramadan.

Talha said the only time he felt really weak was during PE in his freshman year, when he was required to run a mile for track. "I just sat down, rested and told myself, I can get through this," he said.

"The first couple of weeks of Ramadan is pretty bad. I couldn’t get used to it. But the pain goes away, and it becomes a habit, like my mom said. Sometimes I’d forget it’s Ramadan, and be eating something, then stop eating right there, then pray a little bit. The pain isn’t as bad toward the middle and the end," Talha said.

Saifullah, who will begin his first year at Roosevelt in August, said he feels hungrier when he sees other people eating, but he took it upon himself to fast two years ago "because I want to be close to God. I have more self-control — I don’t have to eat so much. And I can’t tease people so much or say bad words like ‘stupid.’"

Many Muslim children about 9 years of age usually want to try fasting a few hours a day or only on weekends because their parents and friends are doing it, according to Nighat Quadri. She said another son, Abdullah, 10, felt fine when he tried it last year.

The children get their reward at the conclusion of Ramadan, Eid al-Fitr, which is "like our Christmas, the biggest celebration of the year," during which gifts are exchanged with family and friends, she said.

The Muslim Association of Hawaii holds a day of festivities at a park, and some Muslims even travel from the neighbor islands to attend, Anwar Quadri added.

Michele Ouansafi said she and her husband, Hakim Ouansafi, head of the Muslim Association, have started special family traditions that have made their children, ages 11 to 14, look forward to celebrating Ramadan and partial fasting. "The beauty of it is, they asked if they could fast," Michele Ouansafi said.

"It’s not an easy thing, but they get a great sense of satisfaction from having done it. They’re proud of themselves. They know, from being hungry and thirsty, that this is how some people feel (all the time), and they don’t have the promise that at the end of the day, they will have a good meal like we do," Ouansafi said.

Sherene Hajiro, a Muslim who has been fasting since puberty, said, "Of course it takes discipline to develop a sense of compassion and humility — for example, compassion towards the homeless, because I do understand how it feels to be hungry and how it feels to be thirsty. You develop humility because sometimes people are not well off, and you extend a helping hand."

The extra time she spends in prayer during Ramadan doesn’t seem like a lot to Hajiro because "it forces you to make time for yourself and reflect. It’s so peaceful. It gives me a break from my routine."