Episode Details

Episode 189: Intermittent Fasting (Religious and Sports)

Future Doctors Carlisle and Kim give recommendations about patients who are fasting for religious reasons, such as Ramadan. They also explain the benefits and risks of fasting for athletes and also debunked some myths about fasting. Dr. Arreaza add input about the side effects of fasting and ways to address them.    

Written by Cameron Carlisle, MSIV (RUSM) and Kyung Kim, MSIV (AUC). Editing by Hector Arreaza, MD.

You are listening to Rio Bravo qWeek Podcast, your weekly dose of knowledge brought to you by the Rio Bravo Family Medicine Residency Program from Bakersfield, California, a UCLA-affiliated program sponsored by Clinica Sierra Vista, Let Us Be Your Healthcare Home. This podcast was created for educational purposes only. Visit your primary care provider for additional medical advice.

Introduction: 

In the last episode on fasting (#179), we explored how intermittent fasting (IF) can help manage type 2 diabetes by improving insulin sensitivity, promoting weight loss, and lowering inflammation. We discussed the benefits of methods like 16:8 time-restricted eating and the 5:2 meal plan, and even compared IF to medications like metformin. Today, we’re bringing that science into real life. We’ll talk about how people fast for religious reasons, like during Ramadan, how athletes use IF to stay in shape, and how we can use IF as a tool in family medicine to support community health and A1c control.

Intermittent Fasting in Religious Practice

Ramadan just ended on 3/30/25, but this is a great time to talk about the broader role of fasting in religion and health. Many faiths incorporate fasting into spiritual practice and understanding this can help us better support our patients.

Islam (Ramadan): Ramadan is a month where Muslims fast from dawn to sunset, focusing on spiritual reflection and self-control. No food or drink is consumed during daylight hours. Despite this, studies have shown that with good planning, fasting during Ramadan does not significantly impair physical performance or metabolic health.

Key health tips for patients observing Ramadan:

• Hydrate well between iftar (sunset) and suhoor (pre-dawn).
• Break the fast with dates and water to gently replenish energy and electrolytes.
• Eat balanced meals with complex carbs, protein, and healthy fats
• Avoid greasy, heavy foods right after fasting
• Light exercise (such as a walk) after iftar is beneficial
• Review medications with a healthcare provider, especially for those on insulin or sulfonylureas.

For example: Metformin should be taken when you break your fast and then again before dawn. If its an extended-release metformin, take it at night. Metformin does not cause significant hypoglycemia and can be continued during Ramadan. Basal insulin is advised to be given at Iftar, and the dose should be reduced by 25-35% if the patient is not well managed. And regarding the fast-acting insulin, it requires a little more reading, so you can look it up and learn about it. 

Judaism: In Judaism, fasting is practiced on days like Yom Kippur and Tisha B’Av, typically lasting 25 hours without food or water. These fasts are spiritual and reflective, and patients with medical conditions may seek guidance on how to participate safely.

Christianity: Many Christians fast during Lent, either by abstaining from certain foods or limiting meal frequency. Some practice partial-day fasts or water-only fasts for spiritual renewal.A branch of Christianity known as The Church of Jesus Christ of Latter-day Saintsoften observe a 24-hour fast on the first Sunday of each month, known as Fast Sunday, where they abstain from food and drink and donate the cost of meals to c