Intermittent fasting and why everyone should be doing it

 

What is intermittent fasting? 

Intermittent fasting is a revolutionary lifestyle change anyone can make. It involves cycling periods of eating and not eating, leading to a vast array of health benefits. Typically this method is performed by consuming all of your meals within an eight-hour window so that for an extended period of the day you are not consuming food or drink (outside of water). This can effortlessly be done; for example, an individual may choose to have their first meal at 12 pm and have their last at 8 pm. This is an easy way to improve lifespan and functionality, coming at the cost of only one meal per day.

 

How will fasting 16 hours affect weight loss? 

Intermittent fasting greatly affects weight loss by causing changes to your metabolism and hormonal processes. During extended periods of fasting insulin levels in the body begin to decrease. This leads to an increase in the hormone glucagon which begins emptying muscle and liver glycogen stores causing a metabolic shift(1). This changes the bodies primary use of fuel from glucose to fats for energy(2).

The lack of insulin also increases the release of human growth hormone (HGH) by the anterior pituitary gland of your brain(3). HGH aids in both fat loss and muscle gain, while also being converted to IGF-1 in the liver, which then competes with insulin receptors on the cell surface. This added competition reduces the amount of insulin being used, leading to less glucose availability and an increase in fat breakdown(4).

With the added benefit of muscle gain due to the rise in HGH, your bodies basal metabolic rate will begin to increase(5). This is the minimum amount of energy your body needs to sustain life. Why this helps with fat loss is because muscle is greatly more demanding than fat, requiring much more energy to be maintained than fat does, leading to more calories burnt during periods outside of exercise(6).

 

Won’t intermittent fasting make me extremely hungry?

If you’re thinking intermittent fasting will make you hungrier, you couldn’t be more wrong. In fact, it foes the complete opposite. Intermittent fasting has been shown to cause genetic adaptations based around standard eating times which cause the hormone ghrelin (hunger hormone), to effectively decrease during times of not eating(7). This overtime will decrease your hunger levels and increase sensitivity to leptin (a hormone with suppresses hunger)(8). Being able to control your appetite is a very important step in weight loss, for if you’re eating less, it is much easier to elicit a caloric deficit.

 

What are common diseases this lifestyle intervention can help prevent?

Outside of weight loss and hunger management, intermittent fasting helps with the prevention of chronic diseases. A very common disease which can be prevented through this lifestyle change is the development of type 2 diabetes. Apart from genetics, the most common cause of type 2 diabetes is related to lifestyle choices, such as a poor diet(9). When consuming large amounts of sugars and refined carbohydrates in your diet, your body can over time become resistant to insulin. This prevents the sugars in your blood from being pulled into your cells and used for energy, leading to increased blood sugar levels. Your pancreas at first will try and compensate for this by creating more insulin, although over time, it won’t be able to keep up. This will lead to the development of type 2 diabetes and cause the sugars to be stored as fat(10). During periods of intermittent fasting, insulin levels begin to drop and insulin sensitivity begins to increase. This lowers the amount of insulin your pancreas needs to produce in order to control blood sugar levels, reducing the risk of developing type 2 diabetes(11).

Due to similar reasons, intermittent fasting has been shown to reduce the risk of developing other chronic diseases such as; cancer, atherosclerosis, rheumatoid arthritis and many, many more(12,13,14). It does this by increasing your body’s resistance to oxidative stress(15). Oxidative stress is caused by an excessive amount of free radicals being produced by poorly functioning mitochondria(16). Although due to intermittent fasting lowering glycogen stores, your cells are forced to use other sources of energy such as fatty acids(1). This causes your cells to go into survival mode, removing any damaged mitochondria and replacing them over time. This reduces the production of free radicals, lowering oxidative stress(17).

 

Does intermittent fasting affect the way I age? 

Another benefit of intermittent fasting is its effect on anti-aging. It does this through a process known as autophagy(18). This is a process where damaged molecules such as; defective cell parts, intracellular pathogens, and misfolded proteins pass into the lysosome of the cell. Here they are recycled into free fatty acids and amino acids which then go through a process known as cell remodeling which is then used as fuel for the body(19). With aging autophagy decreases which allows for cellular damage to accumulate, although with intermittent fasting, autophagy rates can be reset to that of a younger person(20). So by increasing autophagy, intermittent fasting causes the breakdown and clearance of damaged cell parts. This relates to aging for aging is basically just the accumulation of damage. As aging occurs we begin to no longer recycle damage as readily. Therefore one of the best ways to increase clearance of damage, and hence to slow aging, is through intermittent fasting.

 

Will intermittent fasting have any implications on my brain health?

Contrary to belief intermittent fasting is extremely beneficial for brain health and memory. Through the process spoke about above, autophagy breaks down cellular debris and toxins, such as amyloid plaques in your brain(21). Studies have shown that a high level of amyloid plaque between nerve cells in your brain leads to neurodegenerative disorders such as Alzheimer’s and Dementia(22).

While not only preventing neurological disorders, intermittent fasting may also help improve brain function. Intermittent fasting has been shown to release a higher amount of a protein released in nerve cells known as brain-derived neurotrophic factor (BDNF). BDNF attracts new dendrites from nerve cells to connect to other cells or their synapses(23). This causes the brain to wire together new networks which form and consolidate new memories. This process contributes positively to memory, learning, and thinking, while also exhibiting anti-depressant effects.

 

Conclusion:

There are many crazy health benefits associated with intermittent fasting. It is an extremely easy lifestyle change anyone can make, leading to positive outcomes on one’s weight, muscle mass, hunger levels, diseases management, and brain health. For those just starting out and having difficulties, try easing into the process. Start by fasting for 12 hours a day, then 14 hours and finally 16 hours a day. Give this lifestyle change a try for a few months and see how you feel. I guarantee you’ll never go back!!

 

References:

1. Xu K, Morgan K, Gehris A, Elston T, Gomez S. A Whole-Body Model for Glycogen Regulation Reveals a Critical Role for Substrate Cycling in Maintaining Blood Glucose Homeostasis. Computational Biology [Internet]. 2011 [cited 15 November 2018];7(12). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3233304/

2. Knuiman P, Hopman M, Mensink M. Glycogen availability and skeletal muscle adaptations with endurance and resistance exercise. Nutrition & Metabolism [Internet]. 2015 [cited 15 November 2018];12(59). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4687103/

3. ML H, JD V, ML J, MM L, KG A, E S et al. Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men. Endocrine Society [Internet]. 1992 [cited 15 November 2018];74(4):757-65. Available from: https://www.ncbi.nlm.nih.gov/pubmed/1548337

4. Vendelbo M, Jorgensen J, Pedersen S, Gormsen L, Lund S, Schmitz O et al. Exercise and Fasting Activate Growth Hormone-Dependent Myocellular Signal Transducer and Activator of Transcription-5b Phosphorylation and Insulin-Like Growth Factor-I Messenger Ribonucleic Acid Expression in Humans. The Journal of Clinical Endocrinology & Metabolism [Internet]. 2010 [cited 15 November 2018];95(9):E64-E68. Available from: https://academic.oup.com/jcem/article/95/9/E64/2835165

5. Zurlo F, Larson K, Bogardus C, Ravussin E. Skeletal muscle metabolism is a major determinant of resting energy expenditure. The Journal of Clinical Investigation [Internet]. 1990 [cited 15 November 2018];86(5):1423-1427. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC296885/

6. Connolly J, Romano T, Patruno M. Effects of dieting and exercise on resting metabolic rate and implications for weight management. Family Practice [Internet]. 1999 [cited 15 November 2018];16(2):196-210. Available from: https://academic.oup.com/fampra/article/16/2/196/480196

7. Drazen D, Vahl T, D’Alessio D, Seeley R, Woods. Effects of a Fixed Meal Pattern on Ghrelin Secretion: Evidence for a Learned Response Independent of Nutrient Status. Endocrine Society [Internet]. 2006 [cited 15 November 2018];147(1):23-30. Available from: https://academic.oup.com/endo/article/147/1/23/2499980

8. Chausse B, Solon C, Caldeira da Silva C, Masselli dos Reis I, Manchado-Gobatto F, Gobatto C et al. Intermittent Fasting Induces Hypothalamic Modifications Resulting in Low Feeding Efficiency, Low Body Mass and Overeating. Endocrine Society [Internet]. 2014 [cited 15 November 2018];155(7):2456-2466. Available from: https://academic.oup.com/endo/article/155/7/2456/2423365

9. Causes of Type 2 Diabetes. [Internet]. [cited 15 November 2018];. Available from: https://www.webmd.com/diabetes/diabetes-causes#1

10. Insulin Resistance & Prediabetes. National Institute of Diabetes and Digestive and Kidney Diseases [Internet]. [cited 15 November 2018];. Available from: https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance

11. Planned intermittent fasting may help reverse type 2 diabetes, suggest doctors. Science News [Internet]. 2018 [cited 15 November 2018];. Available from: https://www.sciencedaily.com/releases/2018/10/181009210738.htm

12. Jockers D. How to Use Intermittent Fasting Strategies to Prevent or Overcome Cancer. Cancer Prevention [Internet]. 2017 [cited 15 November 2018];. Available from: https://thetruthaboutcancer.com/how-to-intermittent-fast/

13. Horne B, May H, Anderson J, Kfoury A, Bailey B, MCclure B et al. Usefulness of Routine Periodic Fasting to Lower Risk of Coronary Artery Disease among Patients Undergoing Coronary Angiography. HHS Public Access [Internet]. 2009 [cited 15 November 2018];102(7):814-819. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2572991/

14. Khanna S, Jaiswal K, Gupta B. Managing Rheumatoid Arthritis with Dietary Interventions. Frontiers in Nutrition [Internet]. 2017 [cited 15 November 2018];4(52). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5682732/

15. Nurmasitoh T, Utami S, Kusumawardani E, Najmuddin A, Fidianingsih I. Intermittent fasting decreases oxidative stress parameters in Wistar rats (Rattus norvegicus). Universa Medicina [Internet]. 2018 [cited 15 November 2018];37(1). Available from: https://www.univmed.org/ejurnal/index.php/medicina/article/view/462

16. Kresser C. What Really Causes Oxidative Damage? [Internet]. Kresser Institute. 2018 [cited 15 November 2018]. Available from: https://kresserinstitute.com/what-really-causes-oxidative-damage/

17. Bennion D, Wegman M, Guo M. Comment: How fasting might make our cells more resilient to stress [Internet]. SBS News. 2015 [cited 15 November 2018]. Available from: https://www.sbs.com.au/news/comment-how-fasting-might-make-our-cells-more-resilient-to-stress

18. Bergamini E, Cavallini G, Donati A, Gori Z. The Role of Autophagy in Aging. Healthy Aging and Longevity: Third International Conference [Internet]. 2007 [cited 20 November 2018];1114(1):69-78. Available from: https://nyaspubs.onlinelibrary.wiley.com/doi/abs/10.1196/annals.1396.020

19. Klionsky D, Emr S. Autophagy as a Regulated Pathway of Cellular Degradation. Science [Internet]. 2000 [cited 20 November 2018];290(5496). Available from: http://science.sciencemag.org/content/290/5497/1717

20. Cuervo A, Bergamini E, Brunk U, Droge W, Ffrench M, Terman A. Autophagy and Aging: The Importance of Maintaining “Clean” Cells. Autophagy [Internet]. 2017 [cited 20 November 2018];1(3):131-140. Available from: https://www.tandfonline.com/doi/abs/10.4161/auto.1.3.2017

21. Mizushima N, Levine B, Cuervo A, Klionsky D. Autophagy fights disease through cellular self-digestion. a natureresearch journal [Internet]. 2008 [cited 20 November 2018];451:1069-1075. Available from: https://www.nature.com/articles/nature06639

22. Hardy J, Selkoe D. The Amyloid Hypothesis of Alzheimer’s Disease: Progress and Problems on the Road to Therapeutics. Science [Internet]. 2002 [cited 20 November 2018];297(5580):353-356. Available from: http://science.sciencemag.org/content/297/5580/353

23. Lee J, Duan W, Mattson M. Evidence that brain‐derived neurotrophic factor is required for basal neurogenesis and mediates, in part, the enhancement of neurogenesis by dietary restriction in the hippocampus of adult mice. Journal of Neurochemistry [Internet]. 2002 [cited 20 November 2018];82(6). Available from: https://onlinelibrary.wiley.com/doi/full/10.1046/j.1471-4159.2002.01085.x