Ramadan, which begins on April 23 in most countries this year, with the first day of fasting on April 24, is the holiest month in the Islamic calendar.

It involves abstaining from eating, drinking, smoking and sexual relations from dawn to sunset, in the hopes that it will lead to greater "taqwa", or consciousness of God.

Muslims were commanded to fast during Ramadan more than 1,400 years ago, the ancient Greeks recommended fasting to heal the body, and today some scientists are advocating a modified fast for its mental and physical benefits.

Known as intermittent fasting, this modified fast comes in a number of forms that require not eating for 12, 16, or 24 hours at a time. Another form, known as the 5:2 fast, advocates calorie restriction (eating only between 500 and 600 calories) over a period of 36 hours, twice a week.

Eat Stop Eat, a book by Brad Pilon published in 2007, recommended abstaining from eating for 24 hours once or twice a week, giving individuals the freedom to decide when to start and end their fast.

In 2012, Michael Mosley released his TV documentary Eat, Fast and Live Longer and published his best-selling book The Fast Diet, both based on the 5:2 concept of intermittent fasting.

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"In The Fast Diet I advocate a form of fasting called 'time-restricted eating'," Mosley told Al Jazeera.

"This involves only eating within certain hours, similar to the form of fasting practised by Muslims during Ramadan.

"The proven benefits include improved sleep and evidence of reduced risk of some cancers, in particular, breast cancer."

Benefits of fasting

Experts have also found that restricting food intake during the day can help prevent health problems such as high cholesterol, heart disease and obesity, as well as improve mental health and wellbeing.

By not consuming any food, our body is able to concentrate on removing toxins, as we give the digestive system a rest.

Nutritionist Claire Mahy told Al Jazeera: "Fasting allows the gut to cleanse and strengthens its lining. It can also stimulate a process called autophagy, which is where cells self-cleanse and remove damaged and dangerous particles."

Scientists have also been studying the link between diet, gut health and mental wellbeing and, as Mosley explained, fasting can lead to the release of BDNF (brain-derived neurotrophic factor) in the brain.

"This has been shown to protect brain cells and could reduce depression and anxiety, as well as the risk of developing dementia," Mosley added.

Many people who have embraced fasting have also found that, done properly, it has helped them lose fat and gain lean muscle mass.

When not to fast

As with any diet or lifestyle change, there are risks to fasting as it is not suited to everyone.

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Individuals with compromised health or those who are being followed by a physician for any health conditions should consult a doctor before trying it in order to be monitored for some of the side-effects.

"Fasting can lead to low blood glucose levels (BGL), which causes reduced concentration and increased fatigue," explained registered nutritionist Nazmin Islam.

Islam added that sustainable weight loss is only possible with regular fasting and that any weight loss during Ramadan could easily be reversed once an individual returns to their daily eating patterns.

"However, the benefits outweigh the cons. In the long run, fasting, if done correctly, can improve one's digestive system and overall metabolism."