Intermittent Fasting: Food for Thought and Not Your Stomach

Intermittent Fasting: Food for Thought and Not Your Stomach

What is Intermittent Fasting? 

Intermittent fasting (IF) is a way of extending the time that your body has to metabolize food, therefore, causing your body to rely on fat stores (1,2). In some recent research, you may find a few beneficial effects of IF (3). 

The intake of surplus energy (calories), which is then stored as fat (4-6) leads to obesity, diabetes, and cardiovascular disease and are all prevalent health concerns on a national scale (6, 10). Intermittent Fasting is a pattern of eating that alternates between abstaining from food and energy containing drinks (7).  

Where Did Intermittent Fasting Come From? 

Funnily enough, it’s not a ‘new’ way of approaching our typical three square meals a day. The idea of intermittent fasting came from European settlers in the 15th century and quickly spread to the new world (15). IF has become increasingly popular over the years and different forms of it (i.e fasting for religious reasons) used for years (9). 

Isn’t It Just Starvation?

Starvation is a state where your body eats itself down - an extreme form of malnutrition that may involve organ damage or possibly death (16). On the other hand, fasting uses stored nutrients, like sugars and fats, which spares the muscles and organs. Instead of dangerous deprivation, it can lead to some health benefits. If used properly, intermittent fasting can cause weight loss, while lowering blood pressure and other disease risk factors. 

What Happens During Fasting?

Whether you’re fasting for religious or health reasons, we need to explore what happens to the body. We have developed defence mechanisms to ensure survival during times of food scarcity (12), which involves the increase of autophagy, a process where your body removes junk such as mis-folded proteins that may lead to cancer and other diseases (12, 13).

Without the distraction of digesting food, an increase in blood flow throughout your body occurs, thus removing waste, providing increased oxygen to muscles, and may help you focus (9, 12, 13). Alongside the increased blood flow, the body burns through its stored glucose (glycogen). It can provide people with a deeper connection to their hunger cues as we do live in a time where we can snack all day.

The following table outlines the main types of intermittent fasting and the main benefits of them:

Main Type

What

Effects

Complete alternate-day fasting

Alternating between days of  not consuming energy containing drinks and foods with days of consuming energy containing food and drink. Ex. 5:2 diet.

  • Weight loss
  • ↓ glucose levels
  • ↓insulin levels 
  • ↓ total cholesterol
  • ↓ triglycerides 

Modified fasting 

On days of fast, individuals can consume 20-25% of their energy needs.

  • Weight loss
  • ↓insulin levels (not in all cases)

Time-restricted feeding

Fasting only occurs within specific time periods. Ex. 16/8 method.

  • Weight loss
  • ↓ glucose levels
  • ↓ triglycerides 

Table (3, 7-9)

 

According to the graph (14), fat-burning typically starts 12 hours into a fast, when most people would have breakfast. By skipping breakfast, this fat-burning can extend and peak at about 18-20 hours. Hence, this 16:8 or 18:6 hour fasting schedule tends to be very popular. However, when it comes to fasting for weight loss, it’s important to keep in mind that there are many factors affecting the results of these studies (11). For example, diet, body composition, and the fasting routine used. 

Popular Alternatives

Many people can do alternate day fasting or a once a month “cleanse” for 3-5 days. Anything beyond 5 days must be medically supervised. A rule of thumb for borderline underweight people, multi-day fasts may be riskier than beneficial compared to someone with ample body fat. 

Are There Benefits?

The benefits of intermittent fasting, however, are most effective when practiced together with exercising and consuming diets full of whole foods (i.e whole grains, fruits and vegetables, True NOSH products) while reducing consumption of refined sugars (6,9). It can result in weight loss, decreased glucose and improved insulin levels, reduced lipid blood levels, total cholesterol, and triglycerides (3, 7-9) all of which help to decrease your risk of obesity, diabetes, and cardiovascular disease. Furthermore, there is evidence suggesting IF can help improve cognitive functioning and energy levels (3). 

Final Thoughts

Intermittent fasting may be a popular trend that surfaces every now and then but the important thing to remember is whether it’s healthy for your body. Before adopting intermittent fasting regimes, researching the benefits and potential cons of each is recommended so you can find the regime that is sustainable for you and what you want to achieve.

The best way to determine this is to chat with a dietitian before starting any form of fasting as this may not be a suitable practice depending on your health needs. Visit HealthLink, Dietitians of Canada, and BC Dietitians for questions and concerns.

“Lettuce be kind; Squash gossip” 
“Bayleaf in yourself” 

 

Written by Clare Douglas and Amandeep Bains

Proofread by Ev Wong

Edited by Renée Chan

 

References

  1. Anton SD, Moehl K, Donahoo WT, et al. Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity. 2017;26(2):254-268. doi:10.1002/oby.22065. (originally 8)
  2. Barnosky AR, Hoddy KK, Unterman TG, Varady KA. Intermittent fasting vs daily calorie restriction for type 2 diabetes prevention: a review of human findings. Translational Research. 2014;164(4):302-311. doi:10.1016/j.trsl.2014.05.013. (7)
  3. Cabo RD, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine. 2019;381(26):2541-2551. doi:10.1056/nejmra1905136. (10000000)
  4. Hall KD, Heymsfield SB, Kemnitz JW, Klein S, Schoeller DA, Speakman JR. Energy balance and its components: implications for body weight regulation. The American Journal of Clinical Nutrition. 2012;95(4):989-994. doi:10.3945/ajcn.112.036350. (5)
  5. Jung U, Choi M-S. Obesity and Its Metabolic Complications: The Role of Adipokines and the Relationship between Obesity, Inflammation, Insulin Resistance, Dyslipidemia and Nonalcoholic Fatty Liver Disease. International Journal of Molecular Sciences. 2014;15(4):6184-6223. doi:10.3390/ijms15046184. (6)
  6. Ness A. Diet, Nutrition and the Prevention of Chronic Diseases. WHO Technical Report Series 916. Report of a Joint WHO/FSA Expert Consultation. International Journal of Epidemiology. 2004;33(4):914-915. doi:10.1093/ije/dyh209. (3)
  7. Patterson RE, Laughlin GA, Lacroix AZ, et al. Intermittent Fasting and Human Metabolic Health. Journal of the Academy of Nutrition and Dietetics. 2015;115(8):1203-1212. doi:10.1016/j.jand.2015.02.018. (originally 1)
  8. Templeman I, Gonzalez JT, Thompson D, Betts JA. The role of intermittent fasting and meal timing in weight management and metabolic health. Proceedings of the Nutrition Society. 2019;79(1):76-87. doi:10.1017/s0029665119000636. (2)
  9. Alirezaei, Mehrdad, Christopher C. Kemball, Claudia T. Flynn, Malcolm R. Wood, J. Lindsay Whitton, and William B. Kiosses. “Short-Term Fasting Induces Profound Neuronal Autophagy.” Autophagy 6, no. 6 (August 16, 2010): 702–10. https://doi.org/10.4161/auto.6.6.12376.

  10. Collins, Steve. “The Limit of Human Adaptation to Starvation.” Nature Medicine 1, no. 8 (August 1995): 810–14. https://doi.org/10.1038/nm0895-810. 

  11. Johnstone, A. M. “Fasting ? The Ultimate Diet?” Obesity Reviews 8, no. 3 (May 2007): 211–22. https://doi.org/10.1111/j.1467-789X.2006.00266.x.

  12. Malinowski, Bartosz, et al. “Intermittent Fasting in Cardiovascular Disorders—An Overview.” Nutrients, vol. 11, no. 3, 2019, p. 673., doi:10.3390/nu11030673.

  13. Mizushima, N. “Autophagy: Process and Function.” Genes & Development 21, no. 22 (November 15, 2007): 2861–73. https://doi.org/10.1101/gad.1599207.

  14. Naiman, Ted. “Guide to Time-Restricted Eating.” Diet Doctor, Diet Doctor, 25 Aug. 2016, www.dietdoctor.com/intermittent-fasting/time-restricted-eating.

  15. Olson, Samantha. “How 3 Meals A Day Became The Rule, And Why We Should Be Eating Whenever We Get Hungry Instead.” Medical Daily (blog), March 8, 2015. https://www.medicaldaily.com/how-3-meals-day-became-rule-and-why-we-should-be-eating-whenever-we-get-hungry-324892.

  16. Winterman, Denise. “Breakfast, Lunch and Dinner: Have We Always Eaten Them?,” November 15, 2012. https://www.bbc.com/news/magazine-20243692.

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