Free Health and Wellbeing Blog Intermittent Fasting, Weight Management

Well intermittent fasting is thought to be an effective way to lose body fat without losing muscle mass or in other cases increase lean muscle mass with minimal weight gain. This makes the trend not only appealing to the average joe trying to lose a few kilos but also to people in the sporting community, where athletes are trying to hit target weights for competition without losing muscle mass (Tinsley, Gann & La Bounty, 2015).

What Does It Involve?

Intermittent fasting is a form of calorie restriction, there are numerous ways this is achieved, but we will just talk about the main three here today.

1) Time Restricted Feeding 16:8

Is the most common method used, it requires a person to restrict their intake during designated hours and maintain a consistent eating pattern outside these hours. A common diet is the 16:8 which involved fasting for 16 hours consecutively followed by 8 hours of ad libitum food consumption. So a good way to look at this is to eat regularly between the hours of  9am – 5pm and nothing before or after. This is a common method used as many people are easily able to incorporate this into their daily routines (Levy & Chu, 2019).

2) Alternate Day Fasting

This method restricts calories by alternating feeding days with fasting days. Fasting days usually consist of 1 meal providing roughly 25% of the daily calorie requirements.

3) Whole Day Fasting

Whole day fasting is 1 or 2 days of complete or modified fasting (eating 1 meal a day) each week and regular eating the rest of the week (Tinsley, Gann & La Bounty, 2015)

Benefits

There are definitely positive results for fast weight loss and it has also shown to help reduce blood pressure and improve metabolic disease risk markers (Levy & Chu, 2019). The underlying concept of intermittent fasting is during the fasting period, insulin levels drop, initiating the release of stored glucose, resulting in fat loss. Short term studies have found intermittent fasting to help improve insulin sensitivity (Aird, Davies, & Carson, 2018). When exercise is performed during a fasting period, it promotes the utilization of fatty acids and intramuscular triglycerides in the skeletal muscle as the primary source of fuel, this is what stimulates and promotes weight loss. However if training occurs directly before a fasting period or on whole day fasts, it will impair your ability to recover, this is due to the lack of muscle protein synthesis which is important for muscle repair and growth (Burke, 2010).

What To Be Careful Of

Intermittent fasting can be a great way to help reduce calorie intake and boost the metabolism, however it can also cause a lack of concentration due to low blood and brain glucose which can impair decision making (Appleton & Baker, 2015). Another thing to be wary of especially for those who are vegetarian or vegan, is nutrient deficiency, particularly iron and calcium. Finally, for those who do wish to follow this style of diet, it is so important to make sure during the eating times, that you are still eating a well-balanced meal and not eating junk thinking that the fasting time will make up for it. Your body still needs all its nutrients and forms of energy to keep you functioning, deprive your body of these things and not only will you not see the results you are hoping for, but there is also the risk of causing some real damage.

- Alyssa Michel - 

 References

Aird, T., Davies, R., & Carson, B. (2018). Effects of fasted vs fed‐state exercise on performance and post‐exercise metabolism: A systematic review and meta‐analysis. Scandinavian Journal of Medicine & Science in Sports, 28(5), 1476-1493. doi: 10.1111/sms.13054 

Appleton, K., & Baker, S. (2015). Distraction, not hunger, is associated with lower mood and lower perceived work performance on fast compared to non-fast days during intermittent fasting. Journal of Health Psychology, 20(6), 702-711. doi: 10.1177/1359105315573430

Burke, L. (2010). Fasting and recovery from exercise. British Journal of Sports Medicine, 44(7), 502-508. doi:10.1136/502 bjsm.2007.071472

Clipart, (2019). Healthy Plate Cliparts #2604371[Image] Clipart Library. Retrieved from http://clipart-library.com/clipart/782723.htm

Hawley, J., & Morton, J. (2014). Ramping up the signal: Promoting endurance training adaptation in skeletal muscle by nutritional manipulation. Clinical and Experimental Pharmacology and Physiology, 41(8), 608-613

Krol, L. (2019). Transparent Sumo Wrestler Clipart -Rhythm Heaven Megamix Wrestler. [Image]. Clipartkey. Retreived from https://www.clipartkey.com/view/hTToJT_transparent-sumo-wrestler-clipart-rhythm-heaven-megamix-wrestler/

Levy, E., & Chu, T. (2019). Intermittent Fasting and Its Effects on Athletic Performance: A 

Review. Current Sports Medicine Reports, 18(7), 266-269. Doi: 10.1249/JSR.0000000000000614

Leyasw, (2020). Scheme and concept of Intermittent Fasting. Clock face symbolizing the principle of Intermittent Fasting. Vector. Lunch, diet. [Image]. Dreamstime. Retrieved from https://www.dreamstime.com/scheme-concept-intermittent-fasting-clock-face-symbolizing-principle-vector-illustration-infographic-image135089312 

Liu, K., Liu, B., & Heilbronn, L. K., (2020). Intermittent fasting: What questions should we be asking? Physiology & Behavior, 218, 1-8. doi:org/10.1016/j.physbeh.2020.112827

Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016).  Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 48(3), 543-568. doi:10.1249/MSS.0000000000000852 

Tinsley, G. M., Gann, J. G., & La Bounty, P. (2015). Intermittent Fasting Programs and Their Effects on Body Composition: Implications for Weight-Restricted Sports. Strength and Conditioning Journal, 37(5), 60-71. doi: 10.1519/SSC.0000000000000160

Qiu, X., Brown, K., Hirschey, M., Verdin, E., & Chen, D. (2010). Calorie Restriction Reduces Oxidative Stress by SIRT3-Mediated SOD2 Activation. Cell Metabolism, 12(6), 662-667. doi:10.1016/j.cmet.2010.11.015