Most healthy adults could survive weeks without food – not so much without water. Here’s some medical facts and background about fasting, the effect on your body, what to expect and what to avoid.
Food provides most of us with pleasure, and the act of eating is a very sociable activity. Asides from these important secondary benefits, food is there simply to provide the energy for our bodies to sustain its normal functions and for us to carry out our daily activities.
Our bodies have become well adapted over time to deal with any potential future food shortages by storing energy in our bodies, much to our dismay, as fat and glycogen – a stored form of carbohydrate.
Fasting is the practice of deliberate abstention from food and sometimes fluids. It is a widespread practice throughout the world, carried out for both religious reasons and for perceived health benefits.
Everybody is different, but it is generally thought that most healthy adults could survive several weeks without food, relying solely on their stored fat reserves. This is in stark contrast to the situation with water. Unlike camels, which can go long periods of time without water, humans cannot.
Fasting Without Drinking
A large percentage of the human body is comprised of water and it is essential for vital cellular functions. For this reason, fasting without water for more than a few days is unsustainable.
The human body likes to keep the ‘status quo’ when challenged with stressors such as fasting. Previously the body might recognize this as a mini-famine, and knows how to deal quickly and effectively with this to maintain energy production. Despite this, most people will find themselves feeling at least a little lacklustre, perhaps a bitty dizzy and with a bit of a headache. This is common.
Some people claim to feel quite energized when fasting. If you do, that’s great, but don’t go overboard.
It’s probably safe to assume that your body will not thank you for going for a long run or a hitting it hard in the gym.
Fasting is what we call a ‘catabolic’ process. This means that it causes breakdown of tissue (fat and muscle) to be used for energy once stored carbohydrate has been used up. While most of us would be more than happy to depart with a few pounds of fat, we should be trying to hold on to our muscle as much as possible for various reasons.
Fasting With A Medical Condition
For the normally healthy person, short periods of fasting (i.e. 24 hours or less) would normally be dealt with well. The difficulty comes with those who perhaps aren’t so healthy; maybe those who are elderly, frail or have pre-existing medical conditions. There is no ‘one size fits all’ guideline, and these people will need extra considerations of their individual condition to determine whether fasting is safe for them.
Fasting During Pregnancy
This is also the case for pregnancy. Though pregnancy is a normal physiological state of affairs, every woman is different and some women unfortunately suffer from medical problems during pregnancy.
Though this isn’t my area of expertise, my understanding is that many faiths have ‘exemptions’ from fasting for people whom would do themselves harm as a result of fasting. In fact, not only are people exempt from fasting, but they are actively discouraged from doing so.
This should help to ease any feeling of misplaced guilt you might have about not being able to fast for medical reasons.
Read on in our post about Fasting – Medical Tips & Recommendations