Fasting normalizes your insulin and leptin sensitivity and boosts mitochondrial energy efficiency. The amount of sugar in processed diets promotes insulin resistance, a primary driver of chronic disease. Fasting resets your body to use fat as its primary fuel instead of sugar, which reduces the risk of chronic diseases, such as PCOS, heart disease and cancer. 
Fasting normalizes gherlin levels a.k.a “the hunger hormone”. 
Fasting encourages the production of HGH (human growth hormone), which is important for health + fitness. HGH also slows the ageing process and is a fat-burning hormone. 
Fasting decreases the accumulation of oxidative radicals in cells, preventing oxidative damage to cellular proteins, lipids and nucleic acids associated with ageing and disease. 
Fasting boosts a protein called brain-derived neutrophic factor (BDNF). BDNF activates brain cells to convert into new neurons; it triggers other chemicals that promote neural health; and BDNF also protects brain cells from Alzheimer’s and Parkinson’s disease. Studies suggest that restricting meals on alternate days to 600 calories can boost BNDF by 50 – 400%, depending on the brain region. 
BUT I’M AN ATHLETE – WILL I LOSE MY GAINS?
Anthony Mychal has a great blog post on intermittent fasting for athletes. The scientific research he used is based on athletes observing the Ramadhan fasts – when Muslims for one month abstain from food and drink from sunrise to sunset. His research led to the following conclusions:
- Performance is maintained when fasting;
- Whilst body weight is lost, it is mostly fat and not muscle mass;
- Huge feasts before bedtime negatively affect sleep; and
- Experienced Ramadhan athletes handle fasting better and have performances to show for it. 
As Anthony stated on his blog, “a hungry athlete isn’t going to perform well unless they are mentally conditioned to accept hunger as an arbitrary feeling.”  Mind over matter, folks!
If you’ve never fasted before, I would highly recommend speaking to your family doctor. Extra caution must be taken if you’re hypoglycaemic or diabetic, and it is advised that pregnant or nursing mothers, as well as those living with chronic stress should avoid fasting. When you’re given the green light, remember that the key to success is daily compliance, which Dr. Mercola also stresses.
Apart from the month of Ramadhan, I practise intermittent fasting on a daily basis. I do not restrict my caloric intake, however, I tend to eat my first meal around 10 – 11am and stop eating by 7pm at the latest. I also eat my heaviest meal for breakfast, snack on fruits/vegetables and nuts throughout the day, then end off with a light meal. I constantly drink water throughout the day, stopping at around 8pm, so my sleep isn’t interrupted with toilet trips. If I cannot ignore my cravings at night, I snack on either fruits or vegetables.
Eating my heaviest meal for breakfast provides me with the necessary energy to go on throughout the day, whilst eating a light meal in the evening helps to not feel bloated/too full by the time I go to sleep. Intermittent fasting with a focus on eating nutritionally has helped me lose weight, stay alert and be more conscious about what I ingest. Most importantly, fasting has taught me the very important lesson of being mentally strong in order to support myself physically.
I’d love to read your thoughts and/or any tips regarding fasting in the comment section below!
REFERENCES     http://articles.mercola.com/sites/articles/archive/2014/06/14/intermittent-fasting-longevity.aspx   http://anthonymychal.com/2012/05/intermittent-fasting-for-athletes/
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.