Fasting in Ramadan can promote psychological well-being. There are numerous research studies making this case. But how does that work, exactly? How could refraining from food during daylight hours improve well-being? As a psychologist, and having fasted during Ramadan for more than two decades, I think I can provide some insights into the possible mechanisms of action. My first experience fasting during Ramadan came when I was in college. I was not a Muslim at the time, but most of my close friends were. They didn't appear to be particularly religious outside of Ramadan. Still, when the holy month rolled around, they dropped their bad habits and kept the daytime fast. Their transformation impressed me, and it was with a mixture of solidarity and curiosity that I decided to join them. I found fasting difficult at first, but it helped that my friends and I were in it together. The fasting got easier as the month went on and eventually, there was a feeling of being at ease with the emptiness and a sense of mastery and self-discipline. Just as important, I also saw the positive behavioural impacts that fasting had on us in different ways. One friend was calmer and more reflective, another was able to kick bad habits, and all of us became closer. Shortly after my dummy-run, I became a Muslim. The next time Ramadan rolled around, I was immersed in the real deal, the complete package: fasting, reading the Quran, having night prayers and more. It was transformative and character building and quite unlike anything else I had ever experienced. Over the years, I have noticed many similarities between Ramadan and the ideas being promoted by psychologists and psychotherapists. For example, the well-being benefits of the holy month are highly resonant with the Social Comparison Theory. This idea suggests that our self-image and self-evaluations are shaped by comparing ourselves with others. When we evaluate ourselves against one another – and we do – we tend to make "upward" or "downward" comparisons. Upward comparisons – focusing on people who are, for example, more intelligent, more attractive and wealthier – can leave us feeling inadequate. Unsurprisingly, the tendency to make frequent upward social comparisons is predictive of depression. By contrast, downward comparison – focusing on people who have less – leaves us feeling fortunate. For example, fasting can focus the mind on food poverty, famine victims and those who regularly experience thirst and hunger even after the sunsets. Such downward social comparisons make some of us more grateful for what we have. Gratitude frequently leads to pro-social behaviours (for example, charitable giving) aimed at relieving the suffering of others. The idea that gratitude is good for mental health has been well established. Gratitude is a pleasant and powerful social emotion – a gateway emotion that opens the door to other pleasant emotions, such as joy, contentment and excitement. A study published in the neuroscience journal <i>Cerebral Cortex</i> identified links between the experience of gratitude and the neurochemical dopamine, also known as the “pleasure hormone”. Simply pondering the question, "What am I grateful for?" increased dopamine, even if the question was left unanswered. Anyone who has ever broken a difficult day-long fast will know that overwhelming sense of gratitude that occurs as they savour the first sip of a drink or bite of food. Even plain old, precious water tastes delightful. Gratitude is undoubtedly one of Ramadan's greatest gifts. Ramadan is not just about fasting, though; it is also a month of additional Quranic recitation and reading. Another obvious way the holy month promotes psychological well-being lies in the actual content of the Quran. Islam's sacred scripture covers areas as diverse as dietary practice, inheritance law, eschatology (the part of theology concerned with death and the final destiny of the soul and of humankind), and everything in between. However, throughout the text, repeated attention is given to major psychological themes such as patience, forgiveness, acceptance and hope. For many, the Quran provides the ultimate form of bibliotherapy – using the written word to promote mental health. A final aspect of Ramadan that helps promote psychological well-being must be the shared nature of the experience. More than a billion other people are engaged in the same activity, leading to a strong sense of social identity and belonging. Research has underscored the importance of social identity and belonging in promoting well-being and recovery. This "belonging effect" has become widely known as the "social cure". Essentially this is the idea that strengthening social identity (for example, joining a club or playing a team sport) can accelerate illness recovery, promote resilience and reduce relapse. There are numerous studies supporting the well-being benefits of social identity and belonging. The findings suggest that the more profound the sense of belonging to a valued social group, the better the outcomes are for various physical and mental health conditions, including depression. Ramadan, however, is not a panacea. Mental illness prevention and psychological well-being promotion are not the holy month's objectives. They are simply welcome by-products – what we call highly desirable epiphenomena. The actual benefits of Ramadan are, of course, spiritual and the approaching last 10 days and nights of the holy month are a great time for these to be realised.