“Fast and your light will break forth like morning…[and your] healing shall spring forth speedily.” – Isaiah 58: 6-11

Why Fasting?

In our modern age of fad diets and quick nutrition fixes, the practice of fasting remains constant as a tried and true discipline that has been scientifically proven to provide health benefits. Most of the research that support the health benefits have been conducted on animals, and not humans, but the results are stellar. Research has show that fasting can reduce oxidative stress, preserve learning and memory functioning, improve biomarkers of disease, increase lifespan, help maintain weight when coupled with a healthy lifestyle, and slow signs of aging.

So what happens to the body when we fast? Generally speaking within one week of fasting the body is likely to shed weight at an average of .9 kg per day and slowing to .3 kg per day by the third week, due to a loss of sodium. When we fast our body first uses proteins as energy and then eventually begins to go into ketosis, where the body begins to use stored fat as energy. When ketones levels increase in the body they replace glucose, which is normally the body’s’ preferred energy source this decreases the need for gluconeogenesis (processing of generating glucose to maintain energy from things other than carbohydrates). This in turn stops the destruction of proteins, and slows aging.

Now that you know about some of the benefits of fasting, you may be sold on the idea but have no idea where to start? No fear, it’s not as daunting as it seems. Most people like to have a program to follow and a schedule so they can stick to something and not fall off after one day of fasting. The first day, or few days depending on the length of your fast can be the hardest. Preparation is key when fasting, as well as motivation. You want to be clear on your inspiration and fuel it, so that when the going gets rough you can stick with your fasting program to the finish line. If you’ve never embarked on a fast begin with a very short period of time from 24 – 72 hours or 1-3 days maximum.  There are many ways to fast including water fasting, fasting on fresh vegetable and fruit juices, broths, or herbal teas. If those methods are extreme consuming blended foods is an option but offers less of a digestive break from eating. Water fasting is more extreme and should be done under medical supervision, especially if you are committed to an extended period. Also, be sure to consult with a doctor or holistic practitioner before fasting if you have any preexisting medical conditions.

If going cold turkey on food for days seems too intense for you, intermittent fasting or restricting your food intake to a short eating window in one day,  may be a way to still get some of the positive results. Research has proven that intermittent fasting has similar benefits to fasting longer periods when incorporated regularly. One study followed overweight adults with moderate asthma who consumed only 20% of their normal calorie intake on alternate days [5]. The subjects who were able to stick to the diet lost 8% of their body weight over an eight week period, decreased markers of oxidative stress and inflammation, improved  asthma-related symptoms, and several quality-of-life indicators. Another study, found that intermittent fasting was as effective as longer term continuous restriction for improving weight loss, insulin sensitivity and other health biomarkers [3]. Intermittent fasting also improves brain functioning, as a lack of eating for 10-16 hours starts the flooding of ketones in the body, which have been shown to protect memory and learning functionality, as well as slow disease processes in the brain.

The last, and perhaps one of the most important benefits of any type of fasting is that it activates the parasympathetic nervous system which helps to relax, rest, digest food properly, and enables the body to heal itself. Most of us are taught to try to eat our way to health, when in fact, refraining from food allows the body to repair and restore.


  1. Collier, R. (2013). Intermittent fasting: the science of going without. CMAJ : Canadian Medical Association Journal, 185(9), E363–E364.
  2. Dai, Q., Borenstein, A. R., Wu, Y., Jackson, J. C., & Larson, E. B. (2006). Fruit and Vegetable Juices and Alzheimer’s Disease: The Kame Project. The American Journal of Medicine, 119(9), 751–759.
  3. 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.
  4. Huber R, Nauck M, Lüdtke R, Scharnagl H. Effects of one week juice fasting on lipid metabolism: a cohort study in healthy subjects. Forsch Komplementarmed Klass Naturheilkd. 2003 Feb;10(1):7-10. PubMed PMID: 12624474.
  5. Johnson JB, Summer W, Cutler RG, Martin B, Hyun DH, Dixit VD, Pearson M, Nassar M, Telljohann R, Maudsley S, Carlson O, John S, Laub DR, Mattson MP. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radic Biol Med. 2007 Mar 1;42(5):665-74. Epub 2006 Dec 14. Erratum in: Free Radic Biol Med. 2007 Nov 1;43(9):1348. Tellejohan, Richard [corrected to Telljohann, Richard]. PubMed PMID: 17291990; PubMed Central PMCID: PMC1859864.
  6. PAKerndt, P. R., Naughton, J. L., Driscoll, C. E., & Loxterkamp, D. A. (1982). Fasting: The History, Pathophysiology and Complications. Western Journal of Medicine, 137(5), 379–399.


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