Imagine going without food or water for the entire working day, and several hours more. With Ramadan about to start, that's the challenge facing Britain's 1.6 million Muslims. How do they cope?
"Burgers. I crave burgers. I don't even like burgers normally."
Thirty-one-year-old Sumaya Amra is just one of the billion or so Muslims who takes part in the holy month of Ramadan by fasting in daylight hours, each day for 30 days.
Like many young Muslims, London-based Sumaya works in an office and has to fit the demands of a working day around her fast and her food cravings.
Though there are some exceptions, fasting during Ramadan is obligatory for every fit and able Muslim over the age of puberty.
As Muslims believe that their good deeds and actions bring greater reward during Ramadan than at any other time of year, most Muslims perform the fast, even if they do not follow their religion closely throughout the rest of the year.
There is also a convivial, community aspect to the month which many find attractive; but for urban, singleton Muslims living away from home the traditional family evening get-together is often replaced by events held by Muslim organisations, or friends gathering to break the fast en masse.
Ramadan is not purely about hunger; it is used as an exercise in self-control where food, drink (including water), smoking, sexual activity and even gossiping are all abstained from during sunlight hours.
The month is viewed as one for attaining greater spirituality, performing charitable deeds and spending time in prayer and contemplation.
Most sacred of the holy months in Islam
The Koran was first revealed to the Prophet Muhammad
Fasting one of 'five pillars' of Islam
Ramadan moves forward by 10 or 11 days each year as Islamic calendar is lunar
Exemptions include children below the age of puberty, the sick, elderly, pregnant and mentally ill
Celebration of Eid-ul-Fitr marks the end
The spiritual aspect can be the hardest; resisting the desire to lose one's temper despite a thumping caffeine-withdrawal headache and an intrigued non-Muslim colleague asking you what fasting is like while trying to hide their lunchtime sandwich, is somewhat testing.
To answer the two most common questions: no, you really cannot drink water and no, chewing gum is not allowed either.
Unlike their peers in the Middle East who benefit from working hours adapted for Ramadan, Muslims in the West fit Ramadan around the demands of a regular working day.
As well as hunger pangs, Ramadan often means less sleep - those performing the fast are supposed to rise before dawn each morning to eat a meal, known as the suhoor, before beginning their fast.
But Sumaya adapts her fasting ritual: "I often don't get up for suhoor and I know that Islamically this is wrong, but I find the fatigue worse than any hunger I feel. I would rather have a longer sleep and be able to fast and do my work properly."
This year Ramadan is due to start on Thursday 13 September and the late summer days mean that the first fast will break at about 1930 BST. Most Brits love the thought of an extra bit of sunshine, but the thought of a late sunset is not welcomed by all.
"A few years ago when the fast fell in December, it was a lot easier," says Sumaya. "It was like having a very early breakfast and then skipping lunch before having a good dinner."
Khan fasts, but not on fight days
Hunger may seem the biggest difficulty to overcome, but fasting for belief seems to induce a willpower that puts food out of the mind. This willpower can drive even the most ardent of smokers to give up cigarettes - at least until after sunset.
While most healthy Muslims are able to perform the fast without any major problems, as the month progresses the combination of lack of food and sleep can take its toll and a tired or grumpy Muslim colleague or school child can be found staring at the clock in the countdown to iftar time, when they can break their fast after sundown.
While missing out on business lunches and the daily mocca-chocca-skinny latte may be difficult, those with more physical jobs have an even more arduous task. Professional boxer Amir Khan fasts even throughout his training.
"Fasting makes you feel weak," he said last year. "You have to wake up at four or five in the morning to eat, but you're knackered and you don't feel like food, you have to force it down. I wouldn't fast on the day of a fight though."
Many big companies have flexible working policies to help during Ramadan but Neil Payne, CEO of cross-cultural communications consultancy Kwintessential, says that not all companies know what Ramadan entails.
"As a convert to Islam myself, I know what it's like to be working in an office surrounded by people who are not fasting. Our clients are always interested in Ramadan, but they're not always very knowledgeable about it. Even some of the big blue-chip companies in London have little awareness of what Ramadan is."
Owner of the Tiffinbites chain of Indian food restaurants, Jamal Hirani, recognised that breaking the fast and eating the meal afterwards, known as the iftar, was something that Muslim office workers wanted to do away from their desks.
Celebrations mark the end of Ramadan
"I worked in the City myself. I know what it's like to fast at work. You miss out on colleagues' birthday lunches, for example, and then you struggle to try and find a quiet spot to break your fast and have something decent and quick to eat.
"My experiences prompted me to have iftar meals at our restaurants. Customers pre-order their food and it's ready and waiting for them when they come to break their fast."
After sunset, Muslims may eat and drink as normal but overindulgence at night is not in the spirit of Ramadan.
"I try not to be a glutton during Ramadan, that's not what it's about," says Sumaya.
"Admittedly sometimes I do seek out those burgers and I don't know why because they're always such as disappointment, and there's nothing worse than soggy chips. Really it's my mum's food that I miss the most."
Below is a selection of your comments.
Fasting during the summer can be so difficult, with us not being able to eat until 7.30pm having been at work all day and then facing a difficult commute home just makes it all extra difficult. But I think as Muslims, we all realise that these difficulties are all just part of Ramadan and the challenges we have to face, makes it all worth while 30 days or so later when life is back to normal. Helping us appreciate food, or even just a glass of water.
Lara, Ealing, London
I have several Muslim friends and during Ramadan, some of them moan from 8.30 in the morning about food, whereas the others make no mention of it - citing the fact they are lucky they can eat in the morning and in the evening, and billions in the world should be so lucky to have that option. I do admire the dedication of the likes of Amir Khan who needs steady and balanced nutrition to maintain his performance levels in training.
Fasting makes one stronger not weaker and there is the realisation that for others around the world fasting is the norm. Bring it on I say. Ramadan Mubarak to all and lets hope it brings peace and unity for all.
Hanif Rehman, Yorkshire, Gods Country
Lunch is for wimps (Gordon Gecko "Wall Street" 1987)
Dave, Warrington, UK
Ramadan Greetings! As a footy fan, I was always wondering how the footy players cope with fasting. There are many Muslim players in the English League, are they allowed to fast? Some players are recently converted to Islam, Anelka is one of them.
Salam E Mohammed, Saudi Arabia
I would just like to wish all my fellow Muslims Ramadhan Kareem.
Manal Ahmed, Essex