• Fasting is the process of reducing daily nutrients
  • 24 hour fasting has an impact of 9% weight loss in the body
  • 24 hour only water fasting reduces the concentration of Trimethylamine N-Oxide (TMAO) reducing the risk for coronary artery disease (CAD)

Fasting means taking no daily nutrients like food and drinks or reducing them, for a period of time. Even though now it has become a trend, this process dates centuries ago. Therefore, there are many ways of fasting, the most used one being intermittent fasting. Methods of intermittent fasting last 24-72 hours. With the number of people who use these methods rising, there were studies made, which show some advantages of those who use fasting as a health benefiting tool.

In the following paragraphs you will read about 5 benefits of fasting, which were backed by science:

1.Weight loss

2.Preventing and aiding the treatment of cancer

3.Mental health protection

4. Reduction of Trimethylamine N-Oxide

5.Regeneration of immune system

1.Weight loss

24 hour fasting has an impact of 9% weight loss in the body, and in 12-24 weeks of fasting, there is a significant loss of body fat(1). Even though studies reported that fasting and continuous calorie restriction has the same effect in the body weight loss, there is a difference between fasting and continuous calorie restriction that favorite  fasting. Fasting, in contrast to calorie restriction, increases fat loss and at the same time preserves the muscle tissue(2). Another reason why 24 hour fasting contributes to weight loss, is the boost of your metabolism process. The process of eating after a 24 hour fasting increases and promotes the metabolism process. Studies show that metabolism process can speed up to ~14% during a 24 hour fast(3,4).

Figure 1. An animated figure that shows the contribution of fasting in losing weight. Image adapted from (5).

2. Preventing and aiding the treatment of cancer

Fasting may sensitize cancer cells to chemotherapeutic agents. Obrist et al. reported that A549 human non–small cell lung cancer cells that were resistant to the chemotherapeutic drug cisplatin were more susceptible than nonresistant cells to death induced by microtubule-targeting chemotherapeutic drugs, nutrient restriction, and drugs that mimic caloric restriction by reducing acetyl coenzyme A activity. 24 hour starvation periods per week reduced tumor growth and increased survival in mice bearing xenografts of cisplatin-resistant A549 cells compared with mice bearing xenografts of nonresistant A549 cells. Periodic fasting may improve patient results in the context of cisplatin-resistant cancers by depriving the cells of the nutrients they require to repair DNA damaged by the drug(6). Fasting may be very helpful in preventing cancer and enhancing chemotherapeutic activity. A study made in mice showed that alternate-day fasting aided the blocking of tumor formation(7). Fasting is a healthy way to protect normal cells, mice, and potentially humans from the side effects of a variety of chemotherapy drugs. Cycles of starvation were as helpful as chemeo-therapeutic agents in preventing progression of different tumors and enhanced the effectiveness of these drugs against melanoma, glioma and breast cancer cells according to a study published in NCBI in March 2012(8).

Figure 2. Fasting reduces the harmful side effects of chemotherapy. Image adapted from (9).

3. Mental health protection

There are some mental health benefits too if one commits to fasting, even though studies in this area are limited to animals. The improvement of cognitive function and brain structure by intermittent chronic fasting, is shown in a study made in mice (10). Fasting helps relieving inflammation, hence the aid in preventing neurodegenerative diseases. Protection and improved  outcomes for Parkinson’s and Alzheimer’s disease were suggested after some studies in animals(11, 12). The enhancement of cognitive function by increased generation of nerve cells after fasting, was reported(13, 14).

4. Reduction of Trimethylamine N-Oxide

Trimethylamine N-Oxide (TMAO) is an organic compound converted from normal gut bacteria of human microbiota. Its concentration in the blood is increased after consuming food that contains carnitin or lecithin(15). A study published in 2013 suggested that higher concentration of Trimethylamine is associated with coronary artery disease (CAD). 24 hour only water fasting reduces the concentration of TMAO, and indirectly reduces the risk for CAD (16). A long-term impact in preventing CAD can be achieved by reducing plasma levels of TMAO. This can be done by routine, periodic fasting, the study suggests, even though there is space for further investigation(17)

5.Regeneration of the immune system

72 hours fasting can help you to regenerate your immune system. The mechanism behind this relies at the process of recycling white blood cells, and mainly the damaged ones, during the starvation process, in order to save energy. The lowering of white blood cells induces the shifting of stem cells from a dormant state to a state of self-renewal (18).

Figure 3. The prevention of toxins by the regenerated immune system. Image adapted from (19).

Conclusion: You have read some unbelievable benefits that fasting provides, which make our life and our health better. In order to reach the best from fasting, there is a need for a further investigation in finding the best method of fasting we could use.

COPYRIGHT: This article is the property of We Speak Science, a non-profit institution co-founded by Dr. Detina Zalli and Dr. Argita Zalli. The article is written by Veton Guraziu  (University of Prishtina, Kosovo).


  1. https://www.ncbi.nlm.nih.gov/pubmed/26374764
  2. https://www.ncbi.nlm.nih.gov/pubmed/21410865
  3. https://weloni.com/Weight-Loss-Ninja-Blog/reasons-to-fast/
  4. https://www.healthline.com/nutrition/intermittent-fasting-metabolism
  5. https://www.powerofpositivity.com/heres-fasting-helps-lose-weight-rebuild-strengthen-body/
  6. https://stke.sciencemag.org/content/11/542/eaau9719?intcmp=trendmd-stke&_ga=2.174265707.893720074.1564509625-1589388708.1558985051
  7. https://www.ncbi.nlm.nih.gov/pubmed/11835290
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3608686/
  9. https://www.nature.com/articles/s41568-018-0061-0
  10. https://www.ncbi.nlm.nih.gov/pubmed/23755298
  11. https://www.ncbi.nlm.nih.gov/pubmed/17306982
  12. https://www.ncbi.nlm.nih.gov/pubmed/10398297
  13. https://www.ncbi.nlm.nih.gov/pubmed/11220789
  14. https://onlinelibrary.wiley.com/doi/abs/10.1002/%28SICI%291097-4547%2819990715%2957%3A2%3C195%3A%3AAID-JNR5%3E3.0.CO%3B2-P?sid=nlm%3Apubmed&
  15. https://www.nytimes.com/2013/04/25/health/eggs-too-may-provoke-bacteria-to-raise-heart-risk.html
  16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3701945/
  17. https://www.ahajournals.org/doi/abs/10.1161/circ.130.suppl_2.13412
  18. https://news.usc.edu/63669/fasting-triggers-stem-cell-regeneration-of-damaged-old-immune-system/
  19. https://educateinspirechange.org/health/study-fasting-three-days-can-regenerate-entire-immune-system-humans/