May 1, 2022

Intermittent fasting: Ramadan edition

If you’ve been around on social media in the last couple of years, chances are you’ve heard about intermittent fasting. As the name suggests, fasting is “intermittent”, involving the voluntary abstinence from food/drink for a certain number of hours a day, before switching to eating/drinking again. While we may think of this as a recent practice in the health or medical field, intermittent fasting is practiced by various religious groups worldwide, including in Islam, Christianity, Judaism and Hinduism [1]. And, has been practiced since the ancient times – well before any sort of media was around!

As I’m writing this now, millions of Muslims around the world have just finished observing the Holy month of Ramadan, which falls in the ninth month of the Islamic lunar calendar. Fasting, which is practiced from dawn to sunset, involves the abstinence from all food and drink, including water. The fasting period may last between 12-19 hours, depending on geographical location and is practiced for 29-30 days. The spiritual motive behind this reminds Muslims to practice self-discipline, sacrifice, thankfulness, and empathy for the less fortunate.

Given that many of us may associate intermittent fasting with improved health outcomes and weight loss, does Ramadan fasting lead to similar outcomes?

Ramadan meals

There are two main meals consumed during Ramadan, outside of the fasting period. Prior to dawn, Muslims are recommended to consume suhoor (“pre-dawn meal”) which may be a breakfast meal or in some cultures, a dinner-like meal. The fast is traditionally broken with dates at sunset, before consuming iftar (“sundown meal”). While there are no restrictions on eating and drinking between suhoor and iftar, some individuals may not consume additional meals during this time.

So, in a way eating patterns become “nocturnal”. What does this mean for the body?

This is a very broad question – especially considering the possible individual variations in cultural food choice, lifestyle habits, fasting timings, medical history/medications and energy intake during Ramadan. Such factors have presented mixed findings on Ramadan fasting [2], however here are some things research tells us:

Physiological changes in the body

Meal patterns aren’t the only thing changed during Ramadan; physical activity levels and sleeping patterns may shift from an individual’s norm during Ramadan. Physical activity levels may reduce during the daytime and increase during the night, particularly for individuals who choose to exercise after iftar or perform the nightly prayers (called taraweeh). These changes in lifestyle habits inevitably affect various functions in the body, such as the release of hormones involved in hunger signals (e.g. leptin and ghrelin), stress (e.g. cortisol) and growth (e.g. growth hormones). For instance, levels of cortisol are found to be lower in the morning and higher in the evening during Ramadan fasting, when compared to other days of the year.

Energy intake

We’d think that a reduction to two main meals means lower calorie intake throughout the day, however this is not necessarily true. Although this is highly varied between individuals and cultural groups, one study highlighted a lower calorie intake during the first week of Ramadan, followed by a steady increase [3].  As well as this, a higher consumption of processed carbohydrates, including dried fruit, cultural sweets, cakes, pastries and sugar-sweetened beverages during Ramadan has been reported, in comparison to the rest of the year [3,4]. As these foods are energy dense and nutrient poor, consuming a disproportionally large meal at iftar time could explain why total daily energy intake was found to remain unchanged, or higher in healthy adults during Ramadan [5,6].

Weight loss?

Simply put, to achieve weight loss the body needs to be in a state of negative energy balance – that is, energy in (intake) being less than the energy that is used (energy out). Therefore, changes in body composition will come down to the quality and quantity of foods consumed between sunset and dawn during Ramadan. Differences in fasting hours, meal frequency, prolonged periods of standing and praying will come into play; making it inconclusive whether weight loss will occur in an individual’s circumstance [7]. In some instances, authors have suggested that decreases in body weight during Ramadan are likely due to lower fluid intakes [8].

More recently, a comparison of the effects of Ramadan Fasting vs non-Ramadan intermittent fasting found both fasting regimes to be effective in body weight and fast mass losses. However, they noted that weight loss during Ramadan fasting was more apparent in individuals with a higher BMI, likely due to greater fluid losses [9].

Health outcomes

Beyond weight loss, there are several beneficial health outcomes that have been associated with Ramadan fasting, including: abdominal obesity, serum lipids, glucose metabolism and blood pressure levels. Additionally, beneficial changes for the cardiovascular system, including an increase in HDL (aka “good”) cholesterol and decrease in LDL (aka “bad”) cholesterol have been reported in literature [3,10]. It is important to note that the beneficial impacts of Ramadan fasting is dependent on consuming nutritious and high quality foods in the non-fasting hours.

The Bottom line: The effects of Ramadan Intermittent fasting may vary between individuals, due to the many factors that come into play. The reported health outcomes of Ramadan intermittent fasting come down the quality and quantity of foods consumed. It is advisable for individuals with eating disorders, pregnant/breastfeeding women, individuals with chronic health conditions or medication-controlled illness to seek medical advice before fasting. If you’d like to learn more, get in touch with us!


  1. Lessan N, Ali T. Energy Metabolism and Intermittent Fasting: The Ramadan Perspective. Nutrients. 2019;11(5):1192.
  2. Trepanowski J, Bloomer R. The impact of religious fasting on human health. Nutrition Journal. 2010;9(1).
  3. Meo S, Hassan A. Physiological changes during fasting in Ramadan. J Pak Med Assoc. 2015;65(Suppl 1).
  4. Shatila H, Baroudi M, El Sayed Ahmad R, Chehab R, Forman M, Abbas N et al. Impact of Ramadan Fasting on Dietary Intakes Among Healthy Adults: A Year-Round Comparative Study. Frontiers in Nutrition. 2021;8.
  5. Lamri-Senhadji M, Kebir B E, Belleville J, Bouchenak M. Assessment of dietary consumption and time-course of changes in serum lipids and lipoproteins before, during and after Ramadan in young Algerian adults. Singapore Med J. 2009;50(3).
  6. Bakhotmah B. The puzzle of self-reported weight gain in a month of fasting (Ramadan) among a cohort of Saudi families in Jeddah, Western Saudi Arabia. Nutrition Journal. 2011;10(1).
  7. Norouzy A, Salehi M, Philippou E, Arabi H, Shiva F, Mehrnoosh S et al. Effect of fasting in Ramadan on body composition and nutritional intake: a prospective study. Journal of Human Nutrition and Dietetics. 2013;26:97-104.
  8. Lessan N, Saadane I, Alkaf B, Hambly C, Buckley A, Finer N et al. The effects of Ramadan fasting on activity and energy expenditure. The American Journal of Clinical Nutrition. 2018;107(1):54-61.
  9. Correia J, Santos I, Pezarat-Correia P, Silva A, Mendonca G. Effects of Ramadan and Non-ramadan Intermittent Fasting on Body Composition: A Systematic Review and Meta-Analysis. Frontiers in Nutrition. 2021;7.
  10. Roky R, Houti I, Moussamih S, Qotbi S, Aadil N. Physiological and Chronobiological Changes during Ramadan Intermittent Fasting. Annals of Nutrition and Metabolism. 2004;48(4):296-303.