Registered Dietitian and SENR board member Nusrat Kausar discusses fasting and what impact it may have on those who exercise and train whilst observing Ramadan.
Many people have heard of “intermittent fasting”, which can range from the restriction of calories for certain times in the day (time-restricted eating) or to the restriction of calories for multiple days of the week (alternate day fasting) e.g. diets such as the 16/8 diet or the 5:2 diet. This may be for health benefits or to support weight loss aims.
However, fasting during the month of Ramadan is one of the five pillars of Islam. For 29 to 30 days (depending on the lunar calendar), daily fasting is obligatory for all healthy Muslims who have reached puberty. During the fast, Muslims must refrain from eating and drinking between dawn and sunset; and must abstain from ingesting any oral medications, smoking, or sexual activity.
Ramadan is believed to be a holy month; it is not just a case of not eating and drinking, the whole body is in a state of abstinence. It is a time for spiritual contemplation, meditation, and prayer, where Muslims are seeking nearness to God. It is believed that the spiritual rewards for good deeds are multiplied in this month, as the Holy Quran was revealed to the Prophet Muhammad (peace be upon him) in Ramadan. Therefore, Muslims will strongly desire to participate in fasting, even though they could seek exemption, for example, children, the elderly, the sick, or pregnant women.
Fasting during Ramadan affects not only the timing of meals and fluids, but can also disturb medication intake, sleeping patterns, hormone levels, and changes to the circadian rhythm can affect a person’s metabolic state.1
Weight can be also be affected - some maintain weight, whereas others may lose or gain weight. This often depends on whether large meals and treats are consumed on iftar (opening of fast at sunset) versus eating normal, healthy meals.
Studies have demonstrated that fasting in Ramadan can be associated with beneficial effects on the lipid profile of healthy individuals, particularly causing reductions in low-density lipoprotein (bad cholesterol) levels.2
Additionally, intermittent fasting has been associated with positive changes in hormonal responses, oxidative stress, and inflammation.3 Often, if individuals are trying to lose weight, it can sometimes be easier to achieve calorific restrictions in Ramadan as there are only two main meals in the day.
Furthermore, as a consequence of fasting, smoking will be significantly reduced and may help those who are trying to quit achieve this in Ramadan, which will also have positive physiological effects.
In healthy individuals, fasting causes the release of glucose from the body’s glycogen stores or makes glucose from carbohydrates or other macronutrients such as proteins and fat. Glycogen stores in the liver can often provide enough glucose for the brain and muscles for approximately 12 hours.4 Once glycogen stores are depleted, stored fats are broken down to generate ketones, which can then be used as energy by the body, allowing glucose to be preserved for the brain.5
In the UK, Muslims are often fasting for more than 12 hours a day, so will likely have used all their glycogen stores by late afternoon, and be using fat as a source of energy from then onwards. However, if for some reason, suhoor (the dawn meal) was missed, this can lead to a reduction of the glycogen stores sooner and mean the body will use stored fat for energy much earlier in the fasting day.5
However, it should be noted that in patients with diabetes, fasting can be linked with disruptions to the normal glucose metabolism, possibly causing low or high blood glucose levels. Those with type 2 diabetes on multiple diabetes medications or insulin, and particularly those with type 1 diabetes should seek medical advice before fasting during Ramadan.
Studies have often been conducted on athletes fasting during Ramadan, to gain a better understanding of intermittent fasting and its effects on performance. These studies have looked at different types of exercise, such as high intensity, endurance, and resistance exercise.
However, there are not many studies that focus on how to help athletes overcome nutritional barriers to exercising in Ramadan, often they focus on how fasting in Ramadan is harmful to health. This is a gap that needs more research in the future to help Muslims who participate in sports and exercise across the globe.
In the meantime, generally, studies have found that fasting in Ramadan seems to show no improvement in any of the different types of exercise on athletic performance.6 This is likely due to the fact, that during Ramadan no food or drink is consumed during daylight hours, therefore athletes may be affected by many other factors including dehydration, fatigue, and lack of pre and post-nutrition.
Interestingly, this seems to suggest that athletes can maintain their performance abilities for the different types of exercise during Ramadan, which hopefully means that non-elite athletes or individuals doing sports and exercise during Ramadan will also be safe to exercise. Studies have found that athletes can usually eat enough energy or possibly eat too much, particularly at iftar.7
For fluid rehydration, any losses in the day can be corrected in the evening after iftar. Therefore it appears that with good nutritional and hydrational strategies, at the two meals and over the non-fasting period, individuals can participate in sports and exercise whilst fasting in Ramadan with little impact on physical performance.