Fasting has long been an interest to the scientific community, chiefly because of its touted historic benefits to the human body. Fasting is a natural evolutionary survival adaption that allowed us to survive when food was scarce during the winter months, by slowing our bodies natural processes and using the food we did consume more economically.
What are the benefits of fasting?
In recent years, fasting and its supposed health benefits due to this slowing down of processes has become of interest to many. Preliminary studies have suggested fasting could have a number of potential benefits to the body – after all, as a natural survival trait, it makes sense that fasting should have some. Fasting has been touted as a potential aid to reversing the effects of our modern high-calorie, high-sugar, high-salt diets such as obesity, and has even been claimed by some to reverse diabetes. Periods of controlled starvation may also help starve cancer cells, and even slow down the ageing process, as has been discovered in a number of animal species such as monkeys, mice and rats. It has also been said to be an effective treatment for those suffering from hypertension.
How does the body do this?
During periods of fasting, the body responds by slowing its metabolism to conserve energy. This affects everything from ageing to fertility. This can vary a lot between individuals, and often depends on other factors such as body weight, genetic variation and whether water is available. The body, starved of glucose to burn and release energy, switches to burning fat instead. However, too long without food, and the body will enter starvation mode, and start to burn protein from our muscles, which is extremely dangerous.
How long can the body realistically go without food?
How long it takes before an individual’s body reaches this starvation mode varies, depending on starting body weight and individual characteristics. Not eating goes against our nature, we need food to survive. Nevertheless, it has been proven we can survive a relatively long time without sustenance, with a study of hunger strikers varying between 28 and 40 days without food. Gandhi’s longest hunger strike protesting British rule in India lasted around 21 days. Perhaps the longest known case of fasting is Scotsman Angus Barbieri, who fasted for a period of 392 days and managed to survive, drinking just coffee, tea and sparkling water.
What are the dangers of fasting?
Of course, individual ability to fast varies wildly, and fasting can quickly become dangerous if one becomes fixated and starves the body of calories too long. Those working with sufferers of eating disorders warn against such extreme diets, arguing they can turn into obsessive disordered eating habits. Going too long without food has serious adverse effects on the body. An extended time without food begins to make the heart suffer, and those who fast longer than eight weeks are at risk of sudden death. We do need food to survive indefinitely, and those who try to starve themselves of food completely, such as those who practice breatharianism, eventually die of starvation.
Of course, fasting can mean different things, and it should be made clear that the dangers associated with long-term food deprivation are not those associated with short-term religious fasting such as that practiced during the month of Ramadan, where the fast is broken each day.
Given the supposed benefits, it is likely research into fasting will continue, but studies remain at the preliminary stages. Fasting can be extremely dangerous if one fixates on using it to lose weight, and one should never consider an extended period of fasting without talking to a medical professional first.
If you feel like you have been affected by any of the issues discussed in this article, please contact these helplines to discuss them confidentially: Exeter Student Nightline, a confidential listening and information service run by students for students at the University of Exeter on 01392 724 000, or Beat, a charity specialising in eating disorders, on 0345 634 1414.