When Should Children Begin Fasting?

Patient Presentation
An 11-year-old male came to clinic for bug bites. The mother stated that he seemed to get more and they were bigger than those her other children had. During the conversation, the mother said that she was going to start having him fast during an upcoming religious holiday and wanted to know how long he should do it for. The past medical history showed a healthy male. The pertinent physical exam showed a healthy male with normal growth parameters and multiple insect bites that had been scratched on his arms, legs, neck and face. He was Tanner stage 1.

The diagnosis of insect bites was made and the mother and child were counseled about how to avoid the insects and use of insect spray. The physician knew that children should not fast for long periods of time, yet also knew that he would be required by his religion to do so in a few years. The physician discussed the usual sleep and dietary habits with the mother and recommended the child not fast because of his age. However he recognized the religious importance to the family, and recommended that if they were still going to have him fast then only for a couple hours to stretch his normal fasting at night but that appropriate food and water be available for the rest of the day for the child. The physician recommended that this be done under direct parent supervision so someone could recognize any possible problems, stop the fast and food and water could be provided immediately. He also recommended the family talk with their spiritual advisor before beginning any fast and if the advisor recommended a much longer fast then he offered to discuss the issue with the family and advisor together. The mother said she would discuss it with her husband, the child and their advisor.

Fasting means different things to different people. Usually it is refraining from eating and/or drinking for a period of time, or abstaining from certain foods or drinks. Fasting can be caused by physiology (i.e. sleeping), volitional (i.e. due to personal preferences, religious reasons, political protests, etc.) or non-volitional (i.e. pre-surgical fasting, lack of water or food availability, etc.).

An energy source, especially for the brain, and fluid are necessary to maintain a healthy body. If someone is denying calories, after a few hours, glucose that is readily available from the digestive system is depleted. Gluconeongenesis then begins utilizing stores mainly within the liver (gluconeogenesis occurs for hours to days). If the fast continues, then protein is utilized for gluconeogenesis from the muscles (protein utilization occurs for hours to weeks). If the fast continues again, then fat is used as a ketone energy source (fat utilization occurs for days to weeks). With prolonged fasts muscle and fat wasting thus happen. If someone is denying free fluid, then over time dehydration occurs with increased thirst, oliguria/anuria, muscle spasms, cardiac abnormalities, mental status changes, respiratory changes and possible death if not treated.

Fasting combined with other practices may decrease the onset time before the effects occur. For example, fasting and purposeful sweating can increase the severity of dehydration. Fasting along with taking purgatory medications may increase fluid loss and electrolyte abnormalities.

Fasting as a religious/cultural practice can have many benefits including discipline, self-sacrifice, social belonging, and an increased awareness of one’s own spiritual beliefs.

Learning Point
Children can be at particular risk for fasting problems because of their smaller size, surface area, increased metabolic needs, and inability to communicate or help themselves to obtain food and/or fluid. Other individuals are also more vulnerable including the elderly, pregnant and nursing women, and those with temporary or chronic medical conditions. Children have been shown to have decreased cognitive function with short fasts (i.e. skipping breakfast).

Most religious and cultural groups recognize these vulnerable populations and make appropriate exceptions to fasting requirements. For example, Islam recognizes fasting should not occur during Ramadan, for example, for those who are pre-pubertal, mentally ill, elderly, those that are sick, those that are traveling, pregnant or breastfeeding women or women who are menstruating. Judaism recognizes fasting should not occur during Yom Kippur, for example, for those who are pre-pubertal, the elderly, those that are sick, and women who are early post-partum.

Some religious/cultural groups recommend that children nearing puberty begin to do some fasting for them to learn about the physical changes and to participate in the social/spiritual aspects of the practice. They usually do not fast for as long a time as adults though, i.e. a few hours instead of daylight hours or 24 hours for example. Most groups also recommend individuals discuss their personal situation with their medical professionals and spiritual advisors regarding their ability to safely fast.

Questions for Further Discussion
1. What fasting practices are followed by families in your practice?
2. What local resources are available to advise families about religious/cultural fasting practices locally?
3. What are some other benefits of fasting?
4. How common is food insecurity in your practice?

Related Cases

    Symptom/Presentation: Rash

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Child Nutrition and Family Issues.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Pollitt E, Lewis NL, Garza C, Shulman RJ. Fasting and cognitive function. J Psychiatr Res. 1982-1983;17(2):169-74.

Pollitt E, Cueto S, Jacoby ER. Fasting and cognition in well- and undernourished schoolchildren: a review of three experimental studies. Am J Clin Nutr. 1998 Apr;67(4):779S-784S.

Lazarou C, Matalas AL. A critical review of current evidence, perspectives and research implications of diet-related traditions of the Eastern Christian Orthodox Church on dietary intakes and health consequences.
Int J Food Sci Nutr. 2010 Nov;61(7):739-58.

El-Ashi, A. Fasting in Islam. Islamic Society of Rutgers University.
Available from the Internet at http://www.eden.rutgers.edu/~muslims/fasting.htm (cited 8/22/2011).

Author. Overview of Yom Kippur Laws. Chabad-Lubavitch Media Center.
Available from the Internet at http://www.chabad.org/holidays/JewishNewYear/template_cdo/aid/995074/jewish/An-Overview-of-Yom-Kippur-Laws.htm (rev. 2011, cited 8/22/2011).

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Interpersonal and Communication Skills
    17. A therapeutic and ethically sound relationship with patients is created and sustained.
    18. Using effective nonverbal, explanatory, questioning, and writing skills, the healthcare professional uses effective listening skills and elicits and provides information.
    19. The health professional works effectively with others as a member or leader of a health care team or other professional group.

  • Professionalism
    20. Respect, compassion, and integrity; a responsiveness to the needs of patients and society that supercedes self-interest; accountability to patients, society, and the profession; and a commitment to excellence and on-going professional development are demonstrated.
    22. Sensitivity and responsiveness to patients’ culture, age, gender, and disabilities are demonstrated.


    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital