Sometime over the course of this week, you may find some of your colleagues not looking quite themselves. They may be a bit bleary-eyed and yawning constantly, a bit lethargic, they’ll turn down offers of a cup of tea or coffee or popping out for a bit of lunch.

They may not tell you what’s ailing them but – just picking a few random names – if they’re called Mohammed, Abdul, Ali, Amina, Fatima, Aisha, etc, then you’ll probably be able to make an educated guess that it’s Ramadan.

For the uninitiated, it’s the time of year when Muslims embark on a month-long daily ritual of fasting which, if you’ll forgive the pun, makes Lent look like a piece of cake.

From dawn to dusk – and this year that’s about 17 hours-plus in the summer – they’ll abstain from eating, drinking, smoking or ingesting anything bar that which has been medically prescribed for their own safety.

It’s a period when even those who may confess to not being the most devout of Muslims will make the resolution to endure what many would regard as needless torture. To those taking part, it’s the complete opposite.

Fasting during this month – it’s based on the lunar calendar so the start date changes by about 10 days every year – is one of the five pillars, or tenets, of Islam. The others are faith, prayer, pilgrimage to Mecca and Zakat (giving alms to the poor).

Hence, Ramadan is not just about fasting but it’s a time when the generosity of spirit extends to the wallet.

It’s during this time of year that many Muslims decide to fulfil another of their religious obligations, Zakat, or giving to the poor and needy.

Basically, for anyone whose income, savings or jewellery is above the £300 mark or so, they are liable for paying 2.5 per cent to charitable causes. It’s a time of year that’s crucial for charities like the one I work for, Islamic Help.

It helps our work sustaining the deprived in poorer countries and helping the victims of emergencies and conflicts, like Syria. It can also be used to help those in debt or struggling to survive.

So the next time you look at your Muslim colleague and think ‘Poor soul, no food or drink, and he’s going to give over a large chunk of his wages’, remember this: That self-denial means someone in the world will be fed, watered and given an opportunity to succeed in life.

• Mohammed Ilyas is a former Birmingham Post news editor and current communications officer for Islamic Help. www.islamichelp.org.uk