Today marks the start of Ramadan, a time of profound significance for Muslims worldwide. For the next 30 days worshippers will reflect on virtues such as spirituality, sacrifice and patience, as well as fasting – not eating or drinking anything (not even water), from dawn until sunset.
The spiritual benefits of such self-restraint are, of course, at the forefront – but fasting in this way has an effect on the body, too. Indeed, scientific evidence has shown there are health benefits in this kind of intermittent fasting – and there are steps that can help you with the transition to it.
The best way to describe the effect of intermittent fasting is to imagine the body as a hybrid car. When we eat as we normally do – having big meals, snacks or drinks as and when we feel like it – we’re running on readily available fuel. This fuel is primarily glucose from carbohydrates. Think of it as the car using petrol.
However, when we fast, the body’s ‘petrol tank’ (the liver and muscles where the stores are kept) starts to deplete.
When there’s nothing left, usually after eight to 12 hours, the body switches into its ‘electric mode’, tapping into those fat reserves we all carry. It’s like the internal engine revs up and says: ‘Time to burn some of this stored energy.’
This metabolic switch to fat-burning mode is driven by several key processes.
Your blood sugar drops, you produce less insulin (the hormone that signals your body to store fat) and the liver starts to produce ketones.
Ketones are like a super-efficient fuel source for the brain and muscles, derived from the breakdown of fat. The body quite literally turns into a lean, fat-burning machine.
Emer Delaney is a dietician based in London
This transition isn’t always easy. The first few days of fasting can be pretty torrid – you may feel extremely tired, you may also feel more hungry.
This is partly due to the initial drop in blood sugar and the body adapting to using fat as its primary fuel source. There may also be headaches due to dehydration.
If you are fasting for Ramadan this can be a tricky month sleep wise, too. When you start intermittent fasting some nights you’ll sleep soundly, others you’ll toss and turn. This is linked to changes in hormones such as melatonin and cortisol, which regulate sleep-wake cycles, influenced by the fasting state.
So, planning for this month of fasting is important – you want to enjoy it in the healthiest way possible – and continuing with unhealthy habits will make it more of a struggle.
Think about foods that will keep you full and energised. This means a diet balanced with protein, complex carbohydrates and healthy fats.
For suhoor, the pre-dawn meal, this could mean foods such as overnight oats with nuts and berries. Don’t eat sugary treats just before the fast begins or you could experience dramatic blood sugar fluctuations and increased hunger.
Eating excessively at the evening meal could lead to digestive discomfort, especially if the meal is high in fat and processed carbohydrates. High-fat foods can slow digestion, leading to that uncomfortable overly full feeling – whilst processed carbs can also contribute to bloating and gas as they’re quickly digested and ferment in the gut.
Managing water intake is also crucial. You should be drinking the same amount between sunset and dawn that you would on a non-fasting day. Avoid coffee and tea as well – they’re diuretics which could lead to fluid loss later.
Planning for this month of fasting is important – you want to enjoy it in the healthiest way possible – and continuing with unhealthy habits will make it more of a struggle
After five days or so, the body should start to adapt and this can, ultimately, lead to many health benefits.
A 2019 Australian study looking at the effect of Ramadan fasting on the weight and body composition of healthy adults found they lost significant amounts of weight and body fat.
And the bigger their starting body mass index (BMI), the greater amount of weight was lost.
Fasting during Ramadan can have a positive effect on the gut, too, reducing bloating, pain and heartburn, according to a 2023 study published in the European Journal of Clinical Investigation.
It can also have a beneficial effect on lowering blood pressure, according to re-search in the Journal Of The American Heart Association in 2021. It’s thought that this is because, while fasting, the nervous system is in a more relaxed state, known as parasympathetic tone, although more research is needed.
There are also studies pointing to fasting lowering inflammation.
In one 2018 research review published in the Journal Of Nutrition And Intermediary Metabolism, researchers assessed levels of cytokines – proteins that regulate in-flammation in the body – in healthy adults before and after Ramadan.
Excessive levels of cytokines are linked with chronic inflammation, which can be linked to numerous health conditions, including cancer.
At the end of the study, the participants’ cytokine levels were significantly reduced, which could provide a short-term protective effect on healthy people (it’s worth noting that anyone with chronic health conditions is not expected to fast and the health effects may be different in other groups).
There’s an effect on cognitive function, too. According to a 2016 study carried out by King Saud University in Saudi Arabia, during fasting people’s ability to unconsciously shift attention between one task and another improved significantly.
There are downsides of this kind of intermittent fasting – people can become de-hydrated, which is a risk for gallstones.
And inevitably after Ramadan, some will return to their usual lifestyle, leading to weight gain.
But by making the right dietary choices, this time can also be an opportunity for a change and a springboard to longer-term benefits for body and mind.
