Skip to content. | Skip to navigation

The science behind fasting

After the controversy over whether Muslim athletes should fast during the Olympics, Runa Rahman asks if there are any physical benefits to fasting.

What is fasting?

Fasting is ordained in many religions such as Buddhism, Christianity and Islam.  It usually involves a person not consuming drinks, food or both for a period of time. Most will be familiar with the concept of Muslims fasting during Ramadan. During theOlympics  it was asked  whether the performance of the estimated 3,000 Muslim athletes would have been affected due to them fasting or whether they should make up for the days missed afterwards- which is what Abdul Buhari, one of the UK’s best discus throwers, chose to do.

Fasting has also made the news elsewhere due to it being banned in the region of Xingjian of China. They are so keen on reinforcing this ban that they have delivered gifts of food to this region, to ensure that food is eaten when the Muslims would usually abstain from it due to their beliefs.

What are the physical effects of fasting?

Fasting is not always only  done for spiritual reasons. Some people also perform what is known as intermittent fasting and scientists are researching into the many health benefits that could be found in this practice. in an episode of Horizon, Michael Mosley reported an improvement in his IGF-1, cholesterol, glucose and weight amount after fasting in moderation under close supervision for a period of five weeks. 

Fasting doesn’t automatically cause people to lose weight, since once  a person is allowed to eat again, they may overeat to compensate for the hours of eating lost. Their metabolism also slows down whilst abstaining from food and water - which is why many people actually gain weight during Ramadan. 

This can be avoided if you take in small amounts of protein and water throughout the day and thus this form of fasting is a way of reducing caloric intake. Some scientists have tried this concept on volunteers every other day and some others for weekends only. 

Studies have shown that fasting for a short period of time while doing light exercise and having a caloric intake of 800 in liquid form helped promote fat loss. This prevented the person losing too much muscle mass and protein from their body, as when the body does not receive its glucose from the food it consumes, it burns the stored glycogen in fat before muscle.

Should I fast for health?

Remember that scientific studies into the health benefits of fasting are tightly controlled doctors as fasting can be dangerous for people underweight or pregnant. If you are considering fasting for the first time then keep in mind that everyone’s body works differently, the health benefits are still being investigated into and you should see you GP first.

Related links