The benefits of
fasting have been big news lately. But how effective is it? Most people are
interested in it as a weight loss tool, and indeed you can lose weight using
it, but in reality it has many benefits beyond weight loss, and some of them
are quite miraculous.
It has been known for many years that it extends the life
of mice, worms and flies rather dramatically, and even appears to extend the
life of monkeys. Does it extend the life of humans? Many people are convinced
that it does, but the truth is that we're still not sure, although it looks
hopeful.
There's no doubt, however, that it has health benefits in relation to
heart disease, cancer, dementia, and even your mood and well-being. It can't be
called a cure, but it does set the stage for healing by allowing vital parts of
your body to rest and recuperate. There's no doubt that excess eating puts a
burden on your body, and that it needs an occasional rest. Indeed, studies have
shown that if it doesn't rest, it forgoes much of the repair and regeneration
needed for optimal health.
Glucose, Glycogen
and Fat
Your body needs
energy to run properly, and it gets this energy from the food you eat. Food is
turned a form of sugar called glucose. Your cells (and particularly the ones in
your brain) need a constant supply of glucose, and if it gets low you begin to
feel fatigued and weak.
Glucose
circulates in your blood after you eat, and it is used up fairly rapidly as you
go about your everyday tasks. If not replenished, it is, in fact, depleted in a
few hours. This creates a problem: how do you maintain a good supply? Glucose
itself can't be stored, but it can be turned into a form called glycogen that
can be stored in your muscles and liver. From here it can be drawn out and used
as needed. It is usually good for about 10 to 12 hours.
What happens when
it is depleted? The body then turns to the fat cells that are stored throughout
your body. They can be broken down and converted to what is called ketones.
This is, of course, what dieters look for, namely, the loss of fat cells. But
you have to be careful if you remain in this stage for too long. The body soon
begins to break down protein; it can also be converted to glucose through a
rather complicated process. And this causes the loss of muscle - something you
don't want. Indeed, in most diets, a fair amount of the weight loss comes from
muscle loss along with depletion of water (leaving you dehydrated). So don't be
deceived.
Weight Loss
Through Fasting
As I mentioned
earlier, you can lose weight by fasting, but most doctors and dieticians do not
recommend long fasting periods because they can have an adverse effect on your
overall health. In addition, it is difficult for most people to fast for long
periods of time. A better alternative is what is called intermittent fasting in
which you fast on certain days of the week, and eat normally on the others. One
form of this is alternate-day fasting. In this case you fast (or restrict your
calories) on one day and eat normally the next. This works well for some people
but Dr. Michael Mosley of BBC has put forward what he calls the 5-2 fasting
diet. In this diet you restrict your calories only two days a week. He suggests
500 calories for women on these days and 600 for men. This is much easier for
most people to do, and it appears to give the same results as more extended
fasts. But weight loss is not the most important benefit of such a diet, so
let's look at the other benefits.
Health Benefits
of Intermittent Fasting
It may be hard to
believe but there are tremendous benefits to intermittent fasting. The main
thing it does is rest many of the vital parts and organs of your body so they
can do their job better. Some of these are:
It rests the digestive system. This, in turn, helps many other parts of the body.
- It reduces blood sugar. This decreases the production of insulin, and makes it more sensitive and effective. Furthermore, it rests the pancreas.
High blood pressure is controlled.
Detoxification occurs. Fasting helps clear out your body and detoxify it. For this it is important to drink lots of water.
It increases your energy and makes you feel better.
It helps protect you against heart disease and stroke.
It helps rev up your immune system and as a result it fights excess (of chronic) inflammation.
It reduces oxidative stress caused by free radicals in your cells.
Some Surprising
and Different Benefits
One of the
hormones in your body is called IGF-1 (insulin-like growth factor 1); it helps
your cells grow and is particularly important in growing children. As you reach
adulthood, however, it decreases significantly. This is important, since as you
grow older it appears to have adverse effects: it accelerates aging and can
even lead to cancer. So it's not something you want high levels of when you're
older. And studies have shown that intermittent fasting decreases it.
Also, in your
brain is a protein referred to as BDNF (brain-derived neurotrophic factor). It
is important because it has been shown to help stem cells turn into new
neurons. This takes place in a section of the brain called the hippocampus,
which is critical in relation to memory and learning, BDNF has many effects: it
appears to protect against dementia and Alzheimer's disease, and it also acts
as an anti-depressant, suppressing anxiety.
Finally,
intermittent fasting also helps increase autophagy, which is a system in the
cells that gets rid of damaged molecules that could lead to serious
neurological diseases.
Diabetes
Diabetes comes in
two forms: diabetes I and diabetes II. We will be mainly concerned with
diabetes II. As we saw earlier, all cells use glucose as fuel. But it can't get
into the cells without insulin. Insulin is produced in the pancreas according
to the amount of glucose in the blood; it's role is to allow the glucose to
enter the cell. Most of the cells in your body have what are called insulin
receptors that bind to insulin that is circulating in your blood. When a cell
has insulin attached to its surface it allows glucose in, so it obviously plays
an important role in your body. But too much can be detrimental. Insulin
increases your hunger, promotes the storage of fat cells, and it has been
linked to diabetes and heart problems.
One of the major
problems associated with insulin is what is called insulin resistance. In this
case the pancreas produces insulin, but insulin receptors on the cells no
longer work properly, and don't allow glucose to enter as they should. With no
place to go, the glucose continues to circulate in the blood, and the cells
soon begin to starve. The body realizes that something is wrong and the
pancreas produces more insulin in an attempt to get sucrose into the cells, but
this causes the pancreas to overwork, and it eventually begins to wear out. The
result is diabetes II.
Studies have
shown that intermittent fasting improves your insulin sensitivity. This in turn
allows your body to do a better job of controlling your blood glucose levels
after meals, and therefore helps rest your pancreas. Both of these are
important in relation to the prevention of diabetes II.
Rules for Fasting
- It is best to use a 5 - 2 approach, with regular meals 5 days a week, and two days of restricted food (500 calories for women, 600 for men).
Stay hydrated. Drink Plenty of water; it helps flush out toxins.
When not on fasting days (and even when fasting), keep your nutrition maximized. In particular, eat sufficient vegetables, fruits and whole grains.
Remember that 12 hours of fasting is needed for the effect. From 12 to 18 hours is best. It plateau's beyond 18.
You can exercise during fasting periods, but don't overdo it.
Be careful of fasting if you are diabetic.
Barry Parker is a
professor emeritus (physics) at Idaho
State University
who now spends most of his time writing. He is the author of 28 books on
science, health writing, and music, and he has written for the Smithsonian,
Encyclopedia Britannica, Time-Life Books, the Washington Post, and numerous
magazines such as Flyfisherman, Astronomy Magazine, and Sky and Telescope. One
of his books is "You Should Write a Book: Writing it With Style and
Clarity, Publishing Beautiful Pages, Selling Thousands of Copies," It is
based on a course he taught at ISU for several years, and is available through
his website http://www.BarryParkerbooks.com. He is also the author of
"Feel Great Feel Alive" which is on health, fitness and
self-improvement, and he is CEO of Stardust Press. While at ISU he did research
on the DNA molecule and on Einstein's Theory of Relativity. His latest book is
"Learn from Yesterday, Live for Today, Hope for Tomorrow."
