Editor's Note: I recently wrote an article about the benefits of intermittent fasting. Many people questioned the science behind this type of dietary strategy, and insisted that any type of "fasting" was inherently dangerous. To answer those questions (and more), I reached out to Brad Pilon, author of Eat Stop Eat, and nutrition researcher. Here, Pilon describes the science-backed benefits that support fasting, and describes the real way to cleanse your body.
Does your body need to be cleansed?
There are many myths, lots of theories, and certainly plenty of products being marketed for the purpose of cleansing and detox. But most of these products are created with a lack of understanding of how your body works. You see, your body has a built-in cleansing system that is working 24 hours a day; and I'm not talking about your liver or your kidneys. I'm talking about true deep-down cleansing - the cleansing that occurs on the cellular level. The cleansing that is far beyond anything a lemon juice/milk thistle cocktail can provide.
To understand the long-term health benefits of true cleansing, we need to look into a unique process within the human body called 'autophagy'.
Autophagy: The Anti-Aging Solution?
The term autophagy was first coined by Christian de Duve more than 40 years ago. It is derived from the Greek language and means 'eating of self'.[i] Autophagy is a process within your body that is responsible for degrading damaged and defective organelles, cell membranes and proteins. Or put more simply, it is the internal 'custodial system' that your body uses to identify and discard the damaged or malfunctioning parts of a cell.
During any given day of your life there are millions if not billions of cellular reactions that occur in your body, and over time, some of these reactions can lead to damage - just like adding miles to a car eventually leads to wear and tear on its parts. But unlike a car, your body has its own built in mechanics that can identify and repair this damage. But without the proper repair we can build up broken cellular machinery (like damaged mitochondria). When this happens, it is truly toxic to the human body.
Damaged mitochondria are at the top of the list of things that are 'bad for you'. The only reason you probably haven't heard of them is because we don't 'consume' them through our diet, instead they're a by-product of the normal functioning of your body.
An accumulation of damaged cellular machinery like this can cause a wide range of unhealthy effects. Damaged mitochondria can increase the production of reactive oxygen species, accelerating further damage within the cell and the cells around it. This process has been linked to an accelerated aging rate[ii], and many types of chronic disease.
In fact, a lack of proper cellular cleansing (autophagy) is thought to be one of the main reasons for the accumulation of cellular damage within our bodies and the reason for accelerated aging. Don't want to grow old? Autophagy is your solution.
Autophagy is also of increasing interest as a target for cancer therapy,[iii] treatment of alcoholic liver disease,[iv] and as a crucial defense mechanism against malignancy, infection and neurodegenerative disease.[v],[vi],[vii],[viii],[ix] What's more, research has even found a that autophagy can help the body defend against both bacteria and viruses.[x],[xi],[xii],[xiii]
Fasting: The Real Cleanse
So why don't medical professionals simply target autophagy? Turns out, the act of eating tends to get in its way. It seems that lab animals and human beings that eat as they please do too little autophagic recycling. And the more time spent you spend the fed state, the less time you have to really ramp up the autophagic (cellular cleansing) process within your body.
This is where short-periods of fasting come into play. One of the major health benefits of fasting is that it improves autophagy. The principle signal to "turn up" the autophagy dial is the act of entering the fasted state. And if fasting is the signal to turn on autophagy, then eating is the signal to turn it off. Even small amounts of glucose or amino acids are able to inhibit autophagy, as amino acids together with the hormone insulin are its principle negative regulators.[xiv]
It's worth noting that it doesn't take a feast or a junk food binge to negatively affect autophagy. Recent research has shown that as little as 10 grams of amino acids is enough to decrease autophagy markers in otherwise fasting humans. So even a small meal in the middle of a fast may be enough to blunt the increased autophagic processes associated with fasting.
The Power of Fasting: How it Fights Disease, Improves Health, and Builds Muscle
The process of autophagy and its importance in cleansing is the main reason why some researchers are speculating that intermittent fasting can improve neuronal function and overall health in a way that is unique from any other style of dieting or calorie restriction.[xv],[xvi]
The research on fasting and neuronal diseases such as Huntington's and Alzheimer's is also beginning to look very promising, as fasting has been found to cause a rapid and profound upregulation of autophagy in the brain.[xvii],[xviii],[xix] The translation: This has the potential to remove toxic molecules and damaged mitochondria from your neurons.[xx], [xxi],[xxii],[xxiii]
It is also the reason why some people think that intermittent fasting can help regulate and fight against the aging process.Broadly defined, 'aging' refers to the biological changes that occur during a lifetime that result in reduced resistance to stress, increased vulnerability to disease, and an increased probability of death. Autophagy can improve many of these areas.[xxiv]
And the benefits of understand how to turn authophagy "on and off" even extends into the health of your muscles. That is, when you have excess levels of autophagy, you can experience a loss of muscle mass, skeletal fiber degeneration, and weakness.[xxv] In other words, you wouldn't want autophagy "on" all the time, but you do need a healthy balance of autophagy and growth for the optimal functioning of the human body.
Remember: It's not just your workouts that break you down and build you back up - your diet does the same thing, and this break down is just as vital to your long term health as the building back up. Here's what you need to remember:
By allowing for growth when we eat and the autophagic process of repair maintenance and cleansing when we are fasting, we help restore a balance in the cellular maintenance process, not to mention the possible prevention of muscle loss as we age.
The key is there needs to be a balance - You can't overeat all the time or fast all the time without expecting some sort of negative repercussions. It is the optimal balance of these processes that allows for the breakdown of damaged pieces and their replacement with new well-functioning pieces.
By allowing for growth when we eat, and the autophagic process of repair, maintenance, and cleansing when we are fasting, we help restore a balance in the body that may be a missing link in the prevention of many of today's deadly and debilitating diseases such as cancer, Alzheimer's and Huntington's disease, liver disease, and even loss of muscle size and function.
Brad Pilon is one of the world's most recognized advocates of Intermittent Fasting - You can learn more about his approach to intermittent fasting in his newly revised and expanded book Eat Stop Eat.
[i] Deter RL, De Duve C. Influence of glucagon, an inducer of cellular autophagy, on some physical properties of rat liver lysosomes. J Cell Biol 1967;33:437-449
[ii] A.M. Cuervo, E. Bergamini, U.T. Brunk, W. Droge, M. Ffrench, A. Terman, Autophagy and aging: the importance of maintaining ''clean'' cells, Autophagy 1 (2005) 131e140.
[iii] Joon-Ho Sheen, Roberto Zoncu, Dohoon Kim, David M. Sabatini Defective Regulation of Autophagy upon Leucine Deprivation Reveals a Targetable Liability of Human Melanoma Cells In Vitro and In Vivo. Cancer Cell, Volume 19, Issue 5, 613-628, 17 May 2011
[iv] Ding, WX. The emerging role of autophagy in alcoholic liver disease Exp Biol Med 1 May 2011: 546-556.
[v] Hara T, et al. Suppression of basal autophagy in neural cells causes neurodegenerative disease in mice. Nature 2006; 441:885-9
[vi] Komatsu M, et al. Loss of autophagy in the central nervous system causes neurodegeneration in mice. Nature 2006; 441:880-4
[vii] Mizushima N, Levine B, Cuervo AM, Klionsky DJ. Autophagy fights disease through cellular self-digestion. Nature 2008; 451:1069-75
[viii] Alirezaei M, Kiosses WB, Flynn CT, Brady NR, Fox HS. Disruption of neuronal autophagy by infected microglia results in neurodegeneration. PLoS ONE 2008; 3:2906
[ix] Orvedahl A, Levine B. Eating the enemy within: autophagy in infectious diseases. Cell Death Differ 2009; 16:57-69
[x] K. Kirkegaard, M.P. Taylor, W.T. Jackson, Cellular autophagy: surrender, avoidance and subversion by microorganisms, Nat. Rev. Microbiol. 2 (2004) 301e314
[xi] B. Levine, Eating oneself and uninvited guests: autophagy-related pathways in cellular defense, Cell 120 (2005) 159e162
[xii] M. Ogawa, C. Sasakawa, Bacterial evasion of the autophagic defense system, Curr. Opin. Microbiol. 9 (2006) 62e68
[xiii] M.S. Swanson, Autophagy: eating for good health, J. Immunol. 177 (2006) 4945e4951.
[xiv] T Kanazawa, Ikue Taneike, Ryuichiro Akaishi, Fumiaki Yoshizawa, Norihiko Furuya, Shinobu Fujimura, and Motoni Kadowaki. Amino Acids and Insulin Control Autophagic Proteolysis through Different Signaling Pathways in Relation to mTOR in Isolated Rat Hepatocytes. THE JOURNAL OF BIOLOGICAL CHEMISTRY Vol. 279, No. 9, Issue of February 27, pp. 8452-8459, 2004
[xv] Anson RM, et al. Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proc Natl Acad Sci USA 2003; 100:6216-20
[xvi] Duan W, et al. Dietary restriction normalizes glucose metabolism and BDNF levels, slows disease progression, and increases survival in huntingting mutant mice. Proc Natl Acad Sci USA 2003; 100:2911-6
[xvii] Alirezaei M, Kemball CC, Flynn CT, Wood MR, Whitton JL, Kiosses WB. Short-term fasting induces profound neuronal autophagy. Autophagy. 2010 Aug;6(6):702-10.
[xviii] Hara, N., K. Nakamura, M. Matsui, A. Yamamato, Y. Nakahara, R. Suzuki-Migishima, M. Yokoyama, K. Mishima, I. Saito, H. Okana, and N. Mizushima. Suppression of basal autophagy in neural cells causes neurodegenerative disease in mice. Nature. In press
[xix] Komatsu M, et al. Loss of autophagy in the central nervous system causes neurodegeneration in mice. Nature 2006; 441:880-4
[xx] Jaeger PA, Wyss-Coray T. All-you-can-eat: autophagy in neurodegeneration and neuroprotection. Mol Neurodegener 2009; 4:16
[xxi] Hung SY, Huang WP, Liou HC, Fu WM. Autophagy protects neuron from Aβ-induced cytotoxicity. Autophagy 2009; 5:502-10.
[xxii] Donati A, Cavallini G., Paradiso C., Vittorini S., Pollera M., Gori Z. and E. B. Age-related changes in the autophagic proteolysis of rat isolated liver cells: effects of antiaging dietary restrictions. J Gerontol A Biol Sci Med Sci. 2001; 56: B375-383.
[xxiii] Rubinsztein DC. The roles of intracellular protein-degradation pathways in neurodegeneration. Nature. 2006; 443: 780-786
[xxiv] Tohyama D, Yamaguchi A and Yamashita T. Inhibition of a eukaryotic initiation factor (eIF2Bdelta/F11A3.2) during adulthood extends lifespan in Caenorhabditis elegans. FASEB J. 2008; 22: 4327-4337
[xxv] Sandri M. Autophagy in health and disease. 3. Involvement of autophagy in muscle atrophy. Am J Physiol Cell Physiol 2010; 298:C1291-7