Continuing on with the debate on Fasting, this week we look at Intermittent Fasting (IF) that is continuing to rise in popularity for many devotees from Irritable Bowel Syndrome and those with sensitive digestion as well as those after lean muscle development.
So what is 'intermittent fasting'. A process where abstaining from food for a finite period of time is being promoted for better health, advanced relief from digestive disorders and weight loss fanatics. Is this a fad or a new found way to maximise your health and well being? When I started this article I thought it would be easy to get a balanced opinion. I am very much aware now how variable opinion is on the subject.
Intermittent fasting is a process where a meal is skipped or a certain 'window' of ingestion is maintained to manage everything from caloric uptake, efficient digestion and strict utilizing of lean body development. The usual ratio is a daily fast where the window of eating is an 8 hour period. There is also the 5:2 ratio where ingestion is limited to 600cal per day on two days out of seven.
Advocates for IF talk about maximising nutrition in the window of opportunity and taking advantage of the body systems that are in place and affecting our behavoural and circadian rhythms. We were always told 'breakfast is the most important meal of the day'. Well it seems that might not be the case. Devotees claim that by fasting for a 16 hour period you can maximise the body's natural process' to digest and make use of the hormonal and systemic process' in our digestive cycle.
Taking advantage of the body systems and endocrine actions is one of the big arguments for IF. C.A.R (Cortisol Awakening Response) is one of the main arguments supporting the 16 hour fast. Cortisol, wakes us up, gets us ready for the day and depending on your perceived stress level, has various effects on how we wake up. There is a window from 30-50min after waking where cortisol is at it's highest, spurning us into action, getting us up and moving and ready to tackle the day. With this hormone in our system in short term exposure*, there is an associated spike of insulin in the body especially in 'insulin sensitive' people as the body prepares for what is essentially, a perceived threat.
This factor is a key culprit behind advocating the 16hr fast. An already lean and active individual, has a higher sensitivity to insulin - ie their pancreas responds quickly to blood glucose levels. Ingesting food into the system during this spike can send insulin levels through the roof, and then consequently, the post breakfast drop in blood glucose as the insulin levels shuttle glucose to the organs and muscles and out of the blood ready to be used.
The ingestion of protein also illicits a cortisol response^ so far from setting yourself up for energy and active metabolism throughout the day, you may be disrupting your natural eatiing habits. A high protein rich meal in the morning may send your insulin levels sky high as more cortisol is released into your system. This can create a post breakfast hunger that strikes 1-2 hours after eating such a large meal. Fasting during the morning session, can allow these processes to subside and prevent the person from over-stimulating their insulin response and targeting the most appropriate timing for ingestion of food once the insulin is at a more baseline level, thus preventing over ingestion.
This process is not true for all individuals though as there are various nutritional factors that affect the release of hormones and insulin. As stated, this program is used for someone who is already insulin sensitive which is applicable to those who are training at a higher level than your Average Joe. Average Joe has a sluggish system in comparison and may not have the stimulated insulin response of a more physical person. Hence his responses won't have the same endocrine results and he wont' achieve the same results.
Individuals with autoimmune diseases such as systemic lupus, rheumatoid arthritis, colitis and Crohn’s disease have seen a tremendous improvement in symptoms with the incorporation of intermittent fasting. This process reduces the hyper inflammatory processes these individuals undergo and allow for more normalized immune function as their system is able to concentrate on addressing the digestive balances that are so necessary for maintaining health and regulating the effects that these diseases have on the intestinal tract. It's like taking your foot off the accelerator and allowing the system to have a break from input which is perhaps perfect for those with more sensitive Gastro-Intestinal systems.
Fasting seems particular to what you are doing within the fast. If you are active, then prolonged fasting is not advocated as many studies have shown, however a daily fast of prolonged period of reduced ingestion may assist with that elusive 'reduced body fat, lean body figure'. However if you are a performance athlete, fasting may not be appropriate at all, as it downgrades cellular recover and may impact on maximum output in aerobic capacity. So which opinion to take? How much 'performance' do 'I' perform in a day. Is my weekly training trip to the gym or my morning run considered 'training'?
Confused? So was I.
In the tests that I found, it is difficult to get a broad consistency on 'test subjects' to measure the effectiveness and objectively decide whether fasting is the new science of dietetics. There are so many variables that effect the results of fasting, with the 5:2 model seemingly more appropriate for average individuals as opposed to the 'daily fast' model which seems more appropriate to the athletic individual (and even within that there is endurance vs strength or resistance training) as well as those suffering from IBS issues.
I think it is worth repeating that research indicates males respond to fasting productively with increased reproductive capability whilst women actually downgrade their hormonal activity and become less fertile as a result of fasting. This may be of concern to those wanting to fast for weight loss. RED LIGHT ANYONE?
My summation is that Intermittent Fasting really is an individually applicable choice. There are so many variables that effect your system and how you process food and when the best time to eat is. Each argument for and against, is aimed at a specific goal in each case. In studies I have searched, even fluid control has an effect on the 16 hour fast, downgrading results in individuals that perform with or without juices or teas or water.
Perhaps the Ayurvedic Doctors have it right when they say we are all different body types with different modes of ingestion and primary periods when we should and shouldn't eat. This also applies to when we should and shouldn't exercise, which has a major impact on our food ingestion and maximising our nutrient uptake and absorption.
Again, fasting is about desired results? What are you fasting for? Weight loss? Increased performance? Lean muscle gain? A body image? Be vary mindful of what you are doing and what you are advocating - what works for one doesn't necessarily work for the other.
Next week - Sports performance and fasting
* as opposed to long term exposure to cortisol which has the opposite effect
^E.Leigh GIbson - Psychosomatic Medicine, University College, London
Reading List:
"Growth Hormone Secretion During Fasting" - Ho, Velduis, Furlanetto, Evans, Albertii and Thorner (Depts of Internal Medicine/Pharmacology, University of Virginia)
"Top Ten Fasting Myths Debunked" - Martin Berkhan, LeanGains.com Oct 2010
"Fasting and Yoga" - John McWhorter
"Why You Should Starve Yourself a Little Each Day" - George Dvorsky, io9.com
"Why Intermittent Fasting Isn't All it's Cracked Up to Be" - A.Colpo
"IF Will Help Boost the Immune System" - David Jockers
"A Buddhist Perspective on Fasting" - Rev Heng Sure Ph.D www.paramita.typepad.com
