Have you ever tried fasting for 24 hours at a stretch? and by fasting- I mean eating absolutely nothing but drinking only water. One of the ways Gandhi brought India its freedom was by fasting at least 17 times during his lifetime, a couple of them lasting as long as three weeks each. Well, leaving a political reason or a biblical reason for fasting aside, studies have confirmed again and again that it can be one of the best ways to retune your body .

But what actually happens to your body when you fast? why is it so good for your health ?

To answer that, we need to understand what happens in a ‘fed’ state. The ‘fed’ state is referred to a period following a meal when your body is full of nutrients and ‘fasting’ state is referred to when the body is dwindling of its energy resources.

Let’s turn our attention to new born babies to understand these phenomena. New born babies do not have the capacity to store food so that is the reason why they cannot sleep through the night without eating every few hours. The food they consume is immediately used up as energy mainly from the carbohydrates and fats. Since they do not have stored energy residues, the transition from fed to fasting state is rapid- sometimes within three to four hours.

But, in an adult, the liver converts excess carbohydrate or fat intake into stored glycogen or stored fat. So, the transition between the fed and the fasting state is much longer as the body starts digging for stored forms of energy after the first four hours of fed state. There are mainly three of these stored forms of energy- the glycogen (sugars) , amino acids (protein) and the fat.

The first to be used up is the glycogen-

Glycogen is a polysaccharide form of glucose- which simply means biochemically, it is a multiple form of the simplest sugar- glucose. It is stored in two different parts of our body, the muscle and the liver. The muscle glycogen is owned by that particular muscle and is available only to that muscle – which means that the triceps cannot tap into the glycogen stores of your biceps or abdomen muscles.

On the other hand, the liver glycogen is used up by all the body cells for energy and its biggest consumer is the brain. In fact, brain uses up nearly 60 percent of the body’s sugars so most of the liver glycogen is redirected to the brain by digesting that glycogen to glucose.

Fasting for 24 hours can speedily deplete the stores of glycogen present in our body- especially liver starting from as early as four hours from your ‘fed’ state, i.e. your last meal. How about the muscle glycogen then? Yes, there is depletion of muscle glycogen too since we need glucose to do our daily activities and a simple 24 hour fasting can bring down muscle glycogen by as much as 50%.

Now did I just say your body loses muscle glycogen? well, before any bodybuilders in the room faint over this, let me remind you that muscle glycogen is not the same as your hard earned muscle protein. So, there is nothing to fret about as long as you fast in short term periods- preferably around 24 hrs once a week.

The next to go are the proteins and then the fats-

So, once the glycogen is run out of our bodies, the body turns its attention towards amino acids- the building blocks of proteins. And the best place to find this is our muscles- of course. The muscle has readily available amino acids which can be converted into glucose right away in the liver and this way, the brain is never depleted of the needed glucose. But, this happens only after the first 15-16 hours of fasting and actual muscle proteins do not break down until the body reaches a stage of ‘long term’ fasting- generally within two days.

So, what are the benefits of short term fasting-

First of all, depletion of the glycogen stores from our bodies causes suppression of insulin, which can reduce the taste for sugar. So sugar can become something that you would be less fond of taking when you go through these cycles of short-term fasting. As the secretion of insulin is suppressed, the pancreas (which secretes insulin) is rested which benefits our bodies both short-term and also long-term in reducing the risk for diabetes.

The suppression of insulin and presence of glucagon can also benefit in lowering blood pressure as several studies indicate.By resting our digestive system for short periods, we do not produce all the byproducts of digestion- including some dangerous free radicals which are created as a result of converting food into energy. These are the same free radicals which can attack the cells and damage them thus leading to aging. So starvation up to short periods of time can lead to delaying of aging.

According to Mark Mattson from the National Institute of Aging, even limiting calories has this beneficial effect and his statements are backed up by studies in rats and mice which were starved for 24 hours every other day. These fasted rats had a reduction in disease when compared with those fed normal daily diets. According to Mattson, eating less sends a message to body cells to conserve and use energy in a more efficient way- similar to the proven method of building muscle when they are stressed by exercise.

Other than this, some short-term studies have also shown that fasting reduces cancer risks as well as have beneficial effects on the brain- protecting against Alzheimer’s and stroke. But, according to experts, fasting should be kept to windows of 18-24 hours once a week to gain the most out of it. Long term fasting can be harmful to our body- mainly because of the muscle breakdown. After the body uses up all of its stored glucose to make energy, the muscle becomes the target and potentially toxic proteins are released. These proteins partly contain nitrogen and an excess of nitrogen can affect the kidneys and the liver.

Though there is a general agreement over the long term benefits of short term fasting up to 24 hours, starvation or long term fasting ( up to 21 days) should be done under medical supervision after appropriate planning and understanding the health risks of such fasting. Such fasting, termed Medical Fasting is composed of various psychological and medical complications. This is a good article on Medical Fasting..Read More about it here…

Tagged as: fasting