The power of intermittent fasting

Dr. Gorczynski recommends considering intermittent fasting for its weight loss and other health benefits.

Soon after beginning to eat a low-carbohydrate, high-fat diet I found myself eating because it was "time to eat" not necessarily because I was hungry. Without doing much research at the time, I decided to skip a meal and see what happened. Amazingly, I found that when I skipped lunch I made it all the way to dinner. I did not instantly lose all my muscle mass, nor did I experience lack of energy. Then I skipped breakfast and lunch. This felt strange to me as it was contrary to the often recited recommendation to eat many small meals throughout the day. I had repeatedly heard that skipping breakfast increases the likelihood of developing obesity and diabetes. Loss of lean muscle mass was also commonly cited. It seemed like I was embarking on exactly the wrong path.

And yet it made no sense to me to eat when I was not hungry. Especially when I felt better during the fasted state. It seemed to me I had stumbled upon yet another myth of modern nutrition- that humans need to be eating constantly. Thinking back to a time before industrial food and agriculture companies, our ancestors were hunter gatherers and probably experienced widely varying caloric intakes over time. Perhaps intermittent fasting was actually the normal situation back then. Individuals that thrived under such conditions would have been more likely to pass on their genes to future generations. In the modern day, with abundant low nutrient density foods omnipresent, those genes that led to survival back then may  have become counterproductive. Perhaps if we mimic ancestral conditions by varying food intake as opposed to continually flooding our bodies with food we also will thrive. 

There have been many studies on this topic and most show intermittent fasting is likely to be quite good for us. Let's look at some of the major findings:

Weight loss
The concept of the yo-yo diet is well known. Diets, in the traditional sense are temporary, unpleasant restrictions in food quantity that result in some amount of weight loss. Once the diet ends, most people regain all the weight they lost and usually a little bit more. Over time they end up gaining weight. This is not metabolically healthy. Studies investigating intermittent fasting have shown reductions in both body weight and body fat while maintaining or even adding lean body mass. 

Additionally, people tend to find intermittent fasting much more sustainable than simple caloric restriction. This is probably because intermittent fasting may induce a temporary state of nutritional ketosis, especially when done as part of a low-carbohydrate, high-fat diet. Ketosis fuels your body with fat metabolites (ketone bodies) and thus suppresses hunger and provides abundant energy during the fast.

Insulin Sensitivity
Studies consistently show improved insulin sensitivity as a result of intermittent fasting protocols. Remember our discussion of increased baseline insulin secretion that results from exposure to a high-carbohydrate diet? Intermittent fasting reverses this. When not exposed to carbohydrates and proteins for a period of time, the pancreas is able to reduce insulin production and our cells then are exposed to lower insulin levels. The cells in turn will up-regulate their insulin receptors. And just like that, insulin sensitivity improves. It makes sense and studies confirm this. 

Cardio-protective
Heart attack animal models have shown less heart muscle damage after myocardial infarction (heart attack) if the animal was on an intermittent fasting protocol. Additionally, lipid profiles improve with  intermittent fasting. Increased HDL(good cholesterol), decreased triglycerides and decreased total cholesterol were seen in multiple studies. Reduction in systolic and diastolic blood pressure that results from intermittent fasting places a decreased load on the heart. Lastly, intermittent fasting resulted in markedly improved survival in a congestive heart failure animal model. It should be noted that lipid profiles do not necessarily improve in patients with familial hypercholesterolemia, and this technique should probably be avoided in this unique situation.

Neuro-Protective
Intermittent fasting has been found to reduce neuron damage in animal stroke models,  reduce spinal cord demyelination in multiple sclerosis animal models, prevent age-related impairment of brain function, increase neuronal resistance to injury, and may even protect neurons against the degenerative changes that cause Alzheimer's dementia.

Mental Health
Patients commonly report feeling reduced anxiety and improved ability to focus during a fast. Studies report reduced impulsivity, decreased anger, decreased confusion and improved vigor while on an intermittent fasting protocol. 

Immune System Support
Mice adapted to intermittent fasting showed an improved immune response to, and faster clearance of a Salmonella infection compared to those allowed to eat freely.  

Anti-inflammatory
Since we have been discussing a variety of protective effects associated with intermittent fasting, it comes as no surprise to hear that intermittent fasting is associated with reduced inflammatory markers in blood tests. 

​Anti-cancer
Caloric restriction and ketogenic diets have been show to be effective against some cancers in animal models. Dormant cancer cells are dependent on anaerobic glucose metabolism. These cells can result in cancer relapses. Since blood glucose levels can be decreased by up to 40% during fasting, it is felt that fasting may cause these dormant cells to die. Early prostate cancer animal studies show a trend toward improved survival in the intermittent fasting group. 

Radiation Protective
Mice that had adapted to intermittent fasting suffered less damage when exposed to gamma radiation. This protective effect was lost when the mice were allowed to eat freely. 


In addition to the potential health benefits, there are some more immediate, practical benefits of intermittent fasting as well:

It is free. I recommend consuming grass-fed, grass-finished meats, wild caught fish, and organic vegetables whenever possible. These foods are more expensive than the standard versions. Skipping meals helps to offset this expense. 

It is fast. You will not have to spend any time preparing breakfast or lunch on fasting days. 

Improved productivity. The lunch hour is now free-time during which other things can be done. 



How to do it?

1- Train your body to burn body fat for energy. This will greatly facilitate transitioning into intermittent fasting. In my case it happened automatically. Read my earlier blog postings for details. Start with carbohydrate restriction, make sure you are eating the proper amount of protein, and don't be afraid to eat fat. You must eat fat to burn fat. 

2- Your body will adapt to preferentially burning fat over a period of weeks. During the first two weeks you may feel a bit strange, you will likely lose 10 or more pounds. Stay well hydrated and eat healthy fats when hungry. 

3- Within 6 weeks of beginning a low carbohydrate diet many people easily and automatically transition into intermittent fasting. If you would like to try this - simply skip breakfast and lunch and eat a proper dinner. ​Stay well hydrated throughout the day. Black coffee and tea can be consumed during the fast. To sleep properly, stop consuming caffeine by 2PM. Water should be consumed throughout the day. 

4- It appears the beneficial effects of fasting require at least 12 hours without eating, and benefits increase with longer fasting periods. Although fasting can safely be extended beyond 24 hours, most people do not need to. Because eating is also a social event, I prefer fasting from after dinner until dinner the next day. This way I can sit down and enjoy eating with my family, and it provides me an easily sustainable 18-20 hour fasting period. Sleeping through a large portion of this fasting period makes this even easier. 

5- Bulletproof coffee. This is a "biohack" developed by Dave Asprey. Adding some butter and coconut oil or MCT oil to black coffee and then blending, it creates tiny droplets of fat suspended in the coffee. Try a teaspoon of each to start and adjust as needed.  At first this might seem like it would be unpalatable, but I encourage you to try it with an open mind. It not only tastes much better than expected, it has an excellent mouth feel, and makes you feel good. It helps your body to produce ketone bodies (especially if MCT oil is used). It takes advantage of how our body metabolizes dietary fat. When we consume pure fat while in a fasted state, our body will continue to function as if it is fasting. There is no insulin response.  Dave Asprey markets a more refined version of MCT oil he calls Brain Octane Oil. It includes only the 8 chain fatty acids which produce ketone bodies most efficiently. I started intermittent fasting initially drinking bulletproof coffee for breakfast and lunch. I gradually transitioned back to black coffee as my body adjusted and seemed to mobilize stored energy better. 

6- When breaking the fast, do not calorie restrict. Eat a proper meal at a proper pace. A large salad, some high quality meat or fish and a small serving of white rice or sweet potato. Fill your plate and enjoy your meal. 


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Faris MA, Hussein RN, Al-Kurd RA, Al-Fararjeh MA, Bustanji YK, Mohammad MK. Impact of ramadan intermittent fasting on oxidative stress measured by urinary 15-f(2t)-isoprostane. J Nutr Metab. 2012;2012:802924. doi: 10.1155/2012/802924. Epub 2012 Oct 22. PubMed PMID: 23150812; PubMed Central PMCID: PMC3485525.
 
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Razzak RL, Abu-Hozaifa BM, Bamosa AO, Ali NM. Assessment of enhanced endothelium-dependent vasodilation by intermittent fasting in Wistar albino rats. Indian J Physiol Pharmacol. 2011 Oct-Dec;55(4):336-42. PubMed PMID: 23362726.

Harvie MN, Pegington M, Mattson MP, Frystyk J, Dillon B, Evans G, Cuzick J, Jebb SA, Martin B, Cutler RG, Son TG, Maudsley S, Carlson OD, Egan JM, Flyvbjerg A, Howell A. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int J Obes (Lond). 2011 May;35(5):714-27. doi: 10.1038/ijo.2010.171. Epub 2010 Oct 5. PubMed PMID: 20921964; PubMed Central PMCID: PMC3017674.

Lu J, E L, Wang W, Frontera J, Zhu H, Wang WT, Lee P, Choi IY, Brooks WM, Burns JM, Aires D, Swerdlow RH. Alternate day fasting impacts the brain insulin-signaling pathway of young adult male C57BL/6 mice. J Neurochem. 2011 Apr;117(1):154-63. doi: 10.1111/j.1471-4159.2011.07184.x. Epub 2011 Feb 9. PubMed PMID: 21244426; PubMed Central PMCID: PMC3055925.

Jeong MA, Plunet W, Streijger F, Lee JH, Plemel JR, Park S, Lam CK, Liu J, Tetzlaff W. Intermittent fasting improves functional recovery after rat thoracic contusion spinal cord injury. J Neurotrauma. 2011 Mar;28(3):479-92. doi: 10.1089/neu.2010.1609. PubMed PMID: 21219083; PubMed Central PMCID: PMC3119327.

Belkacemi L, Selselet-Attou G, Bulur N, Louchami K, Sener A, Malaisse WJ. Intermittent fasting modulation of the diabetic syndrome in sand rats. III. Post-mortem investigations. Int J Mol Med. 2011 Jan;27(1):95-102. doi: 10.3892/ijmm.2010.556. Epub 2010 Nov 10. PubMed PMID: 21069262.

Thomas JA 2nd, Antonelli JA, Lloyd JC, Masko EM, Poulton SH, Phillips TE, Pollak M, Freedland SJ. Effect of intermittent fasting on prostate cancer tumor growth in a mouse model. Prostate Cancer Prostatic Dis. 2010 Dec;13(4):350-5. doi: 10.1038/pcan.2010.24. Epub 2010 Aug 24. PubMed PMID: 20733612.

Belkacemi L, Selselet-Attou G, Louchami K, Sener A, Malaisse WJ. Intermittent fasting modulation of the diabetic syndrome in sand rats. II. In vivo investigations. Int J Mol Med. 2010 Nov;26(5):759-65. PubMed PMID: 20878099.

Tajes M, Gutierrez-Cuesta J, Folch J, Ortuño-Sahagun D, Verdaguer E, Jiménez A, Junyent F, Lau A, Camins A, Pallàs M. Neuroprotective role of intermittent fasting in senescence-accelerated mice P8 (SAMP8). Exp Gerontol. 2010 Sep;45(9):702-10. doi: 10.1016/j.exger.2010.04.010. Epub 2010 May 9. PubMed PMID: 20460146.

Buschemeyer WC 3rd, Klink JC, Mavropoulos JC, Poulton SH, Demark-Wahnefried W, Hursting SD, Cohen P, Hwang D, Johnson TL, Freedland SJ. Effect of intermittent fasting with or without caloric restriction on prostate cancer growth and survival in SCID mice. Prostate. 2010 Jul 1;70(10):1037-43. doi: 10.1002/pros.21136. PubMed PMID: 20166128.

Wan R, Ahmet I, Brown M, Cheng A, Kamimura N, Talan M, Mattson MP. Cardioprotective effect of intermittent fasting is associated with an elevation of adiponectin levels in rats. J Nutr Biochem. 2010 May;21(5):413-7. doi: 10.1016/j.jnutbio.2009.01.020. Epub 2009 May 7. PubMed PMID: 19423320; PubMed Central PMCID: PMC2854256.

Katare RG, Kakinuma Y, Arikawa M, Yamasaki F, Sato T. Chronic intermittent fasting improves the survival following large myocardial ischemia by activation of BDNF/VEGF/PI3K signaling pathway. J Mol Cell Cardiol. 2009 Mar;46(3):405-12. doi: 10.1016/j.yjmcc.2008.10.027. Epub 2008 Nov 12. PubMed PMID: 19059263.

Salim S, Farooq N, Priyamvada S, Asghar M, Khundmiri SJ, Khan S, Khan F, Yusufi AN. Influence of Ramadan-type fasting on carbohydrate metabolism, brush border membrane enzymes and phosphate transport in rat kidney used as a model. Br J Nutr. 2007 Nov;98(5):984-90. Epub 2007 Sep 3. PubMed PMID: 17764602.

Donato J Jr, Pedrosa RG, de Araújo JA Jr, Pires IS, Tirapegui J. Effects of leucine and phenylalanine supplementation during intermittent periods of food restriction and refeeding in adult rats. Life Sci. 2007 Jun 13;81(1):31-9. Epub 2007 Apr 24. PubMed PMID: 17512018.

Halagappa VK, Guo Z, Pearson M, Matsuoka Y, Cutler RG, Laferla FM, Mattson MP. Intermittent fasting and caloric restriction ameliorate age-related behavioral deficits in the triple-transgenic mouse model of Alzheimer's disease. Neurobiol Dis. 2007 Apr;26(1):212-20. Epub 2007 Jan 13. PubMed PMID: 17306982.

Tikoo K, Tripathi DN, Kabra DG, Sharma V, Gaikwad AB. Intermittent fasting prevents the progression of type I diabetic nephropathy in rats and changes the expression of Sir2 and p53. FEBS Lett. 2007 Mar 6;581(5):1071-8. Epub 2007 Feb 14. PubMed PMID: 17316625.

Martin B, Mattson MP, Maudsley S. Caloric restriction and intermittent fasting: two potential diets for successful brain aging. Ageing Res Rev. 2006 Aug;5(3):332-53. Epub 2006 Aug 8. Review. PubMed PMID: 16899414; PubMed Central PMCID: PMC2622429.

Lee J, Kim SJ, Son TG, Chan SL, Mattson MP. Interferon-gamma is up-regulated in the hippocampus in response to intermittent fasting and protects hippocampal neurons against excitotoxicity. J Neurosci Res. 2006 Jun;83(8):1552-7. PubMed PMID: 16521127.

Mager DE, Wan R, Brown M, Cheng A, Wareski P, Abernethy DR, Mattson MP. Caloric restriction and intermittent fasting alter spectral measures of heart rate and blood pressure variability in rats. FASEB J. 2006 Apr;20(6):631-7. PubMed PMID: 16581971.

Barboza PS, Hume ID. Physiology of intermittent feeding: integrating responses of vertebrates to nutritional deficit and excess.Physiol Biochem Zool. 2006 Mar-Apr;79(2):250-64. Epub 2006 Feb 7. PubMed PMID: 16555185.

Tapia PC. Sublethal mitochondrial stress with an attendant stoichiometric augmentation of reactive oxygen species may precipitate many of the beneficial alterations in cellular physiology produced by caloric restriction, intermittent fasting, exercise and dietary phytonutrients: "Mitohormesis" for health and vitality. Med Hypotheses. 2006;66(4):832-43. Epub 2005 Oct 18. PubMed PMID: 16242247.

Michalsen A, Riegert M, Lüdtke R, Bäcker M, Langhorst J, Schwickert M, Dobos GJ. Mediterranean diet or extended fasting's influence on changing the intestinal microflora, immunoglobulin A secretion and clinical outcome in patients with rheumatoid arthritis and fibromyalgia: an observational study. BMC Complement Altern Med. 2005 Dec 22;5:22. PubMed PMID: 16372904; PubMed Central PMCID: PMC1352378.

Halberg N, Henriksen M, Söderhamn N, Stallknecht B, Ploug T, Schjerling P, Dela F. Effect of intermittent fasting and refeeding on insulin action in healthy men. J Appl Physiol (1985). 2005 Dec;99(6):2128-36. Epub 2005 Jul 28. PubMed PMID: 16051710.

Ahmet I, Wan R, Mattson MP, Lakatta EG, Talan M. Cardioprotection by intermittent fasting in rats. Circulation. 2005 Nov 15;112(20):3115-21. Epub 2005 Nov 7. PubMed PMID: 16275865.

Descamps O, Riondel J, Ducros V, Roussel AM. Mitochondrial production of reactive oxygen species and incidence of age-associated lymphoma in OF1 mice: effect of alternate-day fasting. Mech Ageing Dev. 2005 Nov;126(11):1185-91. PubMed PMID: 16126250.

Mattson MP, Wan R. Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. J Nutr Biochem. 2005 Mar;16(3):129-37. Review. PubMed PMID: 15741046.

Aksungar FB, Eren A, Ure S, Teskin O, Ates G. Effects of intermittent fasting on serum lipid levels, coagulation status and plasma homocysteine levels. Ann Nutr Metab. 2005 Mar-Apr;49(2):77-82. Epub 2005 Mar 29. PubMed PMID: 15802901.

Wan R, Camandola S, Mattson MP. Intermittent fasting and dietary supplementation with 2-deoxy-D-glucose improve functional and metabolic cardiovascular risk factors in rats. FASEB J. 2003 Jun;17(9):1133-4. Epub 2003 Apr 22. PubMed PMID: 12709404.

Anson RM, Guo Z, de Cabo R, Iyun T, Rios M, Hagepanos A, Ingram DK, Lane MA, Mattson MP. Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proc Natl Acad Sci U S A. 2003 May 13;100(10):6216-20. Epub 2003 Apr 30. PubMed PMID: 12724520; PubMed Central PMCID: PMC156352.

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Pedersen CR, Hagemann I, Bock T, Buschard K. Intermittent feeding and fasting reduces diabetes incidence in BB rats.Autoimmunity. 1999;30(4):243-50. PubMed PMID: 10524500.

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