WHAT IS INTERMITTENT FASTING?
There are many variations of fasting. You may refrain from all food and drink, refrain only from food, or constrain eating to a specific time frame. The final variation describes intermittent fasting.
Dr. Krista Varaday, author of The Every-Other Day Diet, advocates for a 5:2 approach – eating whatever you want for 5 days a week, then eating lightly for 2 days a week (consuming an average of 600 calories/day for men and 500 calories/day for women).  Dr. Varaday’s research has shown that the 5:2 regime is easy to maintain and allows for weight loss. 
Dr. Mercola, who also supports the 5:2 regimen, has his own version of intermittent fasting. Instead of eating lightly for two days, he suggests practising intermittent fasting on a daily basis, restricting food consumption to an 8-hour window.  So, if you eat your breakfast at 10am, your final meal should be at 6pm.
Moreover, instead of eating whatever you want, Dr. Mercola prefers maintaining a nutritional diet focusing on: raw organic food, foods high in healthy fats, moderate protein consumption, whilst refraining from large amounts of fruit until your weight and health has normalized. 
FASTING & REJUVENATION
Generally, fasting has many health benefits. British author and journalist Dr. Michael Mosely, learnt that fasting is the secret to living a healthy and long life.
Historically, our ancestors endured periods of feasts and famines, as they relied on hunting and gathering to sustain themselves. Their bodies adapted to efficiently store and use food as energy. Fast forward to the present, technology and increased accessibility has enabled what I call our “consuming culture” – we can eat anything, anywhere, anytime and abundantly.
We must take into consideration the amount of energy it takes for our bodies to digest food. Dr. Mosely discovered that, ‘part of what appears to be driving the disease process [i.e. cardiovascular diseases and cancer] is the fact that we’re eating too frequently […] [I]n constant “feast mode”, our [body forgoes] its natural “repair and rejuvenation programming.”’ 
Fasting gives our digestive system a much-needed break to recuperate, which in turn strengthens our metabolism – one of the keys to a long life.
FASTING & THE LARON MICE
Professor Valter Longo, Director of the University of Southern California’s Longevity Institute, found that one of the links between fasting and longevity may be linked with a hormone called IGF-1 (insulin-like growth factor 1). IGF-1, along with other growth factors, keeps cells active.  However, too much IGF-1 later in life may accelerate ageing. 
Professor Longo demonstrated how the Laron mice, which have been genetically engineered to have low levels of IGF-1, hold the record for longevity extension in a mammal – living approximately 120 to 180 human years!  In addition, Laron mice are largely immune from heart disease and cancer, and usually die from natural causes.  In an Ecuadorian village, Professor Longo learnt that villagers with Laron syndrome, like the mice, do not have high levels of IGF – 1. The villagers live longer and also appear to be immune to cancer.
What does this have to do with fasting? Well, fasting lowers levels of IGF – 1 and appears to also switch on DNA repair genes.
If this hasn’t convinced you of the benefits of fasting, then check out the next post titled, “Intermittent Fasting: Benefits” and keep reading!
REFERENCES     http://www.telegraph.co.uk/lifestyle/9480451/The-52-diet-can-it-help-you-lose-weight-and-live-longer.html     http://articles.mercola.com/sites/articles/archive/2014/06/14/intermittent-fasting-longevity.aspx
The information published in this post was intended for informational and educational purposes only. Nothing in the content should be considered, or used as a substitute for medical advice, diagnosis, or treatment. Consult your physician regarding the applicability of any opinions or recommendations with respect to your symptoms or medical condition.