Fasting is Better than Slowing


The history of all major religions include some form of fasting, from Pagans who would fast in preparation for the spring equinox to Jesus’s forty day fast in the dessert.  Today some religions still include guidelines for monthly, yearly or intermittent fasts while others leave the practice to the discretion of the individual.

But the story about fasting isn’t and shouldn’t only be a religious one.  Here’s why…

The Benefits of Fasting

While religions tend to focus on the spiritual benefits of fasting, abundant research shows fasting’s physical benefits.  For years, we have known that fasting helps slow the aging process by turning on the body’s ability to repair genetic damage, get rid of old cells, and generate new cells.  In fact, calorie restriction (ie, eating less than you “need” to) has long been recognized for its life-extending potential, which is at least partially related to the way it boosts the immune system.

As well, research has shown that intermittent fasting can be a successful approach to helping people achieve and maintain a desirable weight.  This result is not just related to the reduced calorie intake, but also to the way mitochondria (our energy producing power houses) become more efficient with regular fasting.  The impact is so great, in fact, that fasting has been shown to reverse metabolic disease and dysfunction.

Related to specific conditions, regular fasting helps to maintain brain health (particularly related to cognitive function) and improve mood.  Some studies have shown that fasting relieves GERD symptoms, while other research has shown that fasting can starve cancer cells (because they are unable to turn off their growth cycle the way healthy cells can when food is not available).  Plus, fasting helps to reduce the side effects of chemotherapy for cancer patients.

The Body’s Reaction to Fasting

We seem to have forgotten (or perhaps we were never told) that the body can only access stored energy after a period of energy deprivation (such as fasting) has occurred.  This is because the body normally derives its energy from the food we have just eaten.  Put more simply, our bodies cannot access the energy in our fat when we are currently eating or have recently eaten.  This is because the ingestion of food causes the pancreas to release insulin.  Insulin is an anabolic hormone, meaning that it builds things up.  So insulin’s job is to get the glucose and other nutrients out of the blood and put it into cells, while also preventing energy-related compounds already in those cells from getting out.

Only when we have experienced a period of consuming too little food do the catabolic hormones (ie, those that break things down) get released.  These hormones pull stored energy (ie, fat!) out of cells so that it can be carried to cells that need to use it (like muscles).  It seems to me that many people never get to this point because we are constantly eatingWe’ve been told to eat every 2 – 3 hours to “keep our metabolism up”; and honestly, the science just doesn’t support this approach!

What the science does say is that, when food is in short supply, there is a class of proteins called sirtuins that make the mitochondria better at turning fat into energy and turn up their antioxidant defenses.  In other words, not only does fasting allow the body to actually pull fat out of fat cells, it also tells the mitochondria to take that fat and burn it!

Options for Fasting

Although many people think of fasting as abstaining from all food and drink, the word actually has a broader meaning that simply means a restriction of at least some kinds of food or drink for a period of time.  And this is good news!  Because the science certainly shows that benefits can be had from all types, intensities and frequencies of fasting.  So, no need to worry “What Would Jesus Do?” on the fasting front… shorter durations work just fine!

Options for regular fasting include, but certainly are not limited to:

  • Consuming all your calories within a 12 hour period every day and not consuming any calories during the other 12 hours of the day.
  • Reducing your caloric intake significantly for two days of the week and then eating “normally” on the other five days.  This is known as “alternate day fasting.”
  • Consuming only specified cleansing products like water, green tea or supplements for 12 to 96 or more hours. (Matt at Happy Living is pleased with the results he gets from this approach.)

Although you don’t need to fast for 40 days to reap benefits, you do want to be consistent.  So pick an approach and a frequency that you can stick with.  For example, if you’re doing the 12 hrs off food thing, do it every day you possibly can.  If you want to try a 24 hour fast, perhaps once a month is the right frequency.

The reality is that almost all of us fast over night – between our last meal or evening snack and breakfast the next morning.  (This, of course, presumes we aren’t sneaking into the kitchen for a midnight nosh!)  So extending that to ensure a full 12 hours between meals may not be too much of a stretch once you get used to it.  Then, depending on how you feel and your interest, you can bump up your commitment over time and try half day, full day or multi-day fasts.  And soon enough, your body will be humming along in its ideal fat burning, rejuvenating, cancer fighting mode!

If you have a fasting protocol that you like, tell me about it in the comments below.  And, as always, thank you for sharing this information with anyone in your  network that you think can benefit from it!


Note: If you have never fasted before, be aware that fasting will trigger detoxification pathways that can have side effects like tiredness and headaches, similar to giving up caffeine or sugar.  This is temporary and is simply your body switching gears to get rid of the old and bring in the new… which is a good thing! 

Although fasting is safe for most people, be sure to check with your healthcare provider about the safety and efficacy based on your current state of health before beginning a fasting regimen of any kind.


— Chalkiadaki A, Guarente L. Sirtuins Mediate Mammalian Metabolic Responses to Nutrient Availability. Nat Rev Endocrinol. 2012;8(5):287-96.
— Hamblin J. The New Way to Love Food. The Atlantic. January 23, 2014.  Accessed on February 27, 2015.
— Johnstone A. Fasting for Weight Loss: An Effective Strategy or Latest Dieting Trend? Int J Obes (Lond). 2014. doi: 10.1038/ijo.2014.214. [Epub ahead of print]
— Kincaid B, Bossy-Wetzel E. Forever Young: SIRT3 a Shield Against Mitochondrial Meltdown, Aging, and Neurodegeneration. Front Aging Neurosci. 2013;5:48.
— Mattson MP. Lifelong Brain Health is a Lifelong Challenge: From Evolutionary Principles to Empirical Evidence. Ageing Res Rev. 2015;pii: S1568-1637
— Naveed S, Aslam M, Ahmad A. Starvation Based Differential Chemotherapy: a Novel Approach for Cancer Treatment. Oman Med J. 2014;29(6):391-8.
— Newman JC, He W, Verdin E. Mitochondrial Protein Acylation and Intermediary Metabolism: Regulation by Sirtuins and Implications for Metabolic Disease. Journal of Biological Chemistry. 2012;287(51):42436-43.
— Obregon MJ. Adipose Tissues and Thyroid Hormones. Front Physiol. 2014 Dec 11;5:479.
— Yasawy MI, Randhawa MA. GERD is Becoming a Challenge for the Medical Profession: Is There Any Remedy? Hepatogastroenterology. 2014;61(134):1623-6.

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  • Hi Stephanie,
    Aurelie sent me the link to your post on Fasting.
    I have been doing the Intermittent Fasting for the past 7 months and it’s changed my life, for the better of course! I do 16hrs/day without any food from my last meal in the evening (so sleeping helps, since you’re fasting while asleep anyway) and work out (gym/swim/yoga) in the morning on an empty stomach. No need to say that I’ve slimmed down big time, but from the 3rd day of fasting I could already feel more positive, in a better mood and full of energy – without me knowing about these benefits! My skin is even better and I feel like the aging process has stopped! Also, not ill once in the past 7 months and winters are cold in the UK…
    Since then I’ve been trying (successfully sometimes!) to convert my friends. For me, IF is definitely the way forward and I would never go back to having breakfast. Thanks for your thorough post! R

    • Thank you for your kind words, Roman, and for sharing about your experience! I love that you have found a way of eating that works so well for you. And how wonderful that making the change to IF has had such broad benefits for you. Honestly, that’s my favorite thing to hear from people. 🙂 I hope you continue to have good results with it!

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