Growing up, I was taught breakfast was always the most important meal of the day. So, you can understand my surprise when intermittent fasting (IF) was introduced to me. No breakfast? No more midnight snacks? The horror.

However, IF is not a diet. It is a pattern of eating.

In the simplest of terms, intermittent fasting is the act of only allowing yourself to eat in a certain window of 6-10 hours. For example, if you eat dinner at 8pm you wouldn’t eat again until 12pm the next day.

How does intermittent fasting work?

As you eat, the body takes that energy from the food and stores it in the liver as glycogen. Glycogen is a “readily mobilized storage form of glucose”.1 When you fast for 10-12 hours, your body begins to deplete that glycogen storage. When that glycogen storage is very low, the body releases fat cells into the bloodstream. These fat cells travel to your liver and are converted into energy for your body. This means that your body starts to burn fat for energy rather than the food you’d typically be eating all day to keep your body going.2

Why intermittent fast? What are the benefits?

  • Weight loss: Fasting increases your metabolic rate due to low insulin levels, high growth hormone production levels, and an elevated supply of noradrenaline. All of this helps breakdown the fat in our bodies, allowing us to burn more calories, and thus lose more weight.3
  • Improvements in brain health: According to the Center for Law and the Biosciences at Stanford Law School, our brains heighten synaptic plasticity when we are fasting. This is the place in our brain where most of our learning and memory occurs. Intermittent fasting also improves cognitive function, increases growth of new neurons, and prevents and alleviates depression and anxiety.4
  • Cellular repair and disease prevention: When we fast, our cells begin the autophagy process. The autophagy process removes harmful proteins and clears out any damaged cells. Autophagy also helps boost cellular health and repair, “giving it a key role in preventing diseases such as cancer, neurodegeneration, cardiomyopathy, diabetes, liver disease, autoimmune diseases and infections”.5
  • Heart health: According to studies conducted by the National Center for Biotechnology information, short-term fasting has the ability to lower total cholesterol, LDL cholesterol, and triacylglycerol concentrations. Lowering these risk factors has the ability to promote a healthy heart and prevent cardiovascular disease. 6 7
  • Inflammation reduction:  When there is an imbalance between free radicals and antioxidant defense, inflammation in the body occurs. This development is referred to as oxidative stress. IF has been proven to reduce oxidative stress and inflammation, making IF an important role in pain control and prevention.8
  • Longer lifespan: In a study, by the Gerontology Research Center of the National Institute on Aging in Baltimore, MD, found that rats on an IF regime lived 83% longer than rats consuming a diet of eating when they please. While health studies conducted on animals should be taken with a grain of salt, given what we know about inflammation reduction and increase metabolism during IF, IF may have the possibility to extend lifespan. 9 10

What are the different methods? Which one is right for me?

Water and non-caloric beverages are permitted for consumption during all fast.

  • The 16/8 fast: This is the most common method of IF. This method involves eating in an 8-hour window during the day and fasting for the other 16 hours of the day, every day. While many people stop eating at 8pm, skip breakfast the next morning, and begin eating again at noon, pick a time frame that works best for your body and lifestyle.11
  • The 24-hour fasts: This method involves eating normally during the week and reserving one or two days out of the week to do 24 full hour fasts. This method should be done with caution. Doing a 24 hour fast is more difficult that the 16/8 fast due to the hunger, especially if you are exercising during the fast.12
  • The 5:2 fast: Similar to the 24-hour fast, this calorie deficit fast is comprised of eating 500-600 calories two days out of the week and eating normally the other five days of the week.13
  • The Every-Other-Day fast: This fast alternates every other day, meaning that you would eat normally one day, fast the next, eat normally the day after that, and so on. This fast is one of the more difficult, as you will be living with increased hunger half of your week.14
  • The Warrior Diet: This fast is comprised of fasting during the day and eating a large meal within a 4-hour window at night.15

If starting a structured IF plan every day seems too challenging for your schedule or health, skipping a meal here and there is a great way to begin. While a certain method might work well for you, it is important to eat a variety of healthy foods during the process to receive the health benefits intermittent fasting has to offer.

References

  1. Berg, Jeremy M. “Glycogen Metabolism.” Advances in Pediatrics. January 01, 1970. https://www.ncbi.nlm.nih.gov/books/NBK21190/.
  2. Anton, Stephen D., Keelin Moehl, William T. Donahoo, Krisztina Marosi, Stephanie Lee, Arch G. Mainous, Christiaan Leeuwenburgh, and Mark P. Mattson. “Flipping the Metabolic Switch: Understanding and Applying Health Benefits of Fasting.” Advances in Pediatrics. February 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5783752/.
  3. Gunnars, Kris, BSc. “10 Evidence-Based Health Benefits of Intermittent Fasting.” Healthline. August 16, 2016. https://www.healthline.com/nutrition/10-health-benefits-of-intermittent-fasting#section2.
  4. Bair, Stephanie. “Intermittent Fasting: Try This at Home for Brain Health.” Stanford Law School. January 9, 2015. https://law.stanford.edu/2015/01/09/lawandbiosciences-2015-01-09-intermittent-fasting-try-this-at-home-for-brain-health/.
  5. Glick, Danielle, Sandra Barth, and Kay F. Macleod. “Autophagy: Cellular and Molecular Mechanisms.” Advances in Pediatrics. May 2010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2990190/.
  6. Gunnars, Kris, BSc. “10 Evidence-Based Health Benefits of Intermittent Fasting.”
  7. Varady, K. A., S. Bhutani, E. C. Church, and M. C. Klempel. “Short-term Modified Alternate-day Fasting: A Novel Dietary Strategy for Weight Loss and Cardioprotection in Obese Adults.” Advances in Pediatrics. November 2009. https://www.ncbi.nlm.nih.gov/pubmed/19793855.
  8. Johnson, J. B., W. Summer, R. G. Cutler, B. Martin, D. H. Hyun, V. D. Dixit, M. Pearson, M. Nassar, R. Telljohann, S. Maudsley, O. Carlson, S. John, D. R. Laub, and M. P. Mattson. “Alternate Day Calorie Restriction Improves Clinical Findings and Reduces Markers of Oxidative Stress and Inflammation in Overweight Adults with Moderate Asthma.” Advances in Pediatrics. March 01, 2007. https://www.ncbi.nlm.nih.gov/pubmed/17291990/.
  9. Gunnars, Kris, BSc. “10 Evidence-Based Health Benefits of Intermittent Fasting.”
  10. Goodrick, Charles L., Donald K. Ingram, Mark A. Reynolds, John R. Freeman, and Nancy L. Cider. “Effects of Intermittent Feeding Upon Growth and Life Span in Rats.” Karger Publishers. April 06, 2009″ target=”_blank” rel=”noopener noreferrer”>
  11. Gunnars, Kris, BSc. “6 Popular Ways to Do Intermittent Fasting.” Healthline. June 4, 2017. https://www.healthline.com/nutrition/6-ways-to-do-intermittent-fasting#section3.
  12. Gunnars, Kris, BSc. “6 Popular Ways to Do Intermittent Fasting.”
  13. Gunnars, Kris, BSc. “6 Popular Ways to Do Intermittent Fasting.”
  14. Gunnars, Kris, BSc. “6 Popular Ways to Do Intermittent Fasting.”
  15. Gunnars, Kris, BSc. “6 Popular Ways to Do Intermittent Fasting.”