A Colby Community Website for ST297, Fall 2018

Intermittent Fasting: Just Another Gimmick?

Diet fads are not new. Every so often, a group of scientists or fitness enthusiasts will release a new diet which they claim will help you lose weight and revitalize your health. These include the Atkins diet, Paleo diet, and plant-based diet, just to name a few. There is another fad, however, that has slowly crept into popular culture which claims to have more significant benefits than any other diet. There are many scientists, in fact, who tout it as a scientific breakthrough and should be practiced by all individuals. This new diet is called intermittent fasting. Researchers claim that a regulated regimen of periodic fasting and feeding can help increase metabolism, slow aging, and even help prevent cancer (Virgin). There are many skeptics who believe this is indeed another fad. I, however, along with many scientific researchers, believe that intermittent fasting is truly beneficial for human health and can be the key to preventing obesity and several diseases.

Modern scientists are not the first ones to promote this practice. Fasting has long been an integral component of many religions, including Judaism, Hinduism, Islam, and Christianity, with each religion claiming that fasting provides spiritual and health benefits. Researchers over time have studied the health effects of several religions’ fasting routines, and found that religious followers who fasted regularly exhibited many positive health benefits. These benefits came about due to the reduction in consumption of meat, animal products, refined carbohydrates, and sugary food and drink, components which many consider the pillars of the modern American diet. The favorable effects of their fasts included the lowering of body mass and total cholesterol (Trepanowski). In addition, scientists found that fasters had low levels of low-density lipoproteins (LDL), which is considered “bad” cholesterol as it is the main component in fatty plaques which can clog blood vessels. As a result, researchers found that religious fasters had a much lower risk of obesity and heart disease, and overall were much healthier than the average American.

The tradition of religious fasting is what prompted Valter Longo, a biochemist and director of the USC Longevity Institute, to begin studying caloric restriction and fasting during his Ph.D. research. Originally from Italy, he saw that elders from his village, who were devout Catholics and always fasted during Lent, lived much longer lives than average; his father lived until the age of 91 (McFarling). As such, the question as to exactly why they lived so long simmered in the back of Longo’s mind.

Throughout his research, Longo has worked with mice and was one of the first to showcase that putting mice on a fasting regimen produced positive health results. He saw that they resisted tumors and inflammatory diseases, and they did not end up with diabetes, high cholesterol, or fatty livers. Further studies conducted by Longo and his team have time and again confirmed his earlier results. In addition, trials with human subjects are currently being conducted in order to mimic the results in human models, with early results looking very similar to those of mouse models (Patterson). As a result of his work, Longo is almost certain that the fasting regimen practiced by the residents of his village has allowed many of them to live long and healthy lives.


Main stages of modern intermittent fasting/feeding

The modern intermittent fasting diet is very simple. Intermittent fasting consists of fasting for a set period during the day and having a small window of time during which one eats food. There are several variations within the diet regarding time spent fasting versus feeding, however the main consensus amongst advocates is that the longer the fasting period, the more benefits one will see. The most common fasting/feeding window is 18 hours of fasting and 6 hours of feeding, but many practitioners choose to fast for roughly 23 hours and consume one meal per day. These long periods of fasting is what produces the diet’s results. According to researchers, fasting essentially gives the body’s cells a break from processing all the food that an average person eats during the day. With this, cells can focus on something called autophagy, which is the process by which cells degrade and recycle cellular components, in order to maintain homeostasis and overall cell health (Glick et al.). This essentially allows cells time to cleanse themselves, producing profound effects on biological systems in the process.

Proponents of intermittent fasting claim that the diet has many positive effects on the body. A study conducted in 2010 found that food-restricted mice had upregulated function of autophagy in their brain cells; this is a major reason why fasting is believed to potentially prevent neurodegenerative diseases such as Alzheimer’s disease and can boost overall brain function (Alirezaei et al). Mouse models have also been used to show how fasting can improve immune function as well as improve cardiovascular health.

Intermittent fasting stimulates fat loss, bolsters the gut microbiota which improves immune and digestive function, as well as improves the health of neurons in the brain.

In addition, the diet has been shown to prevent obesity and cause fat loss in obese mice (Belman). This is especially exciting for physicians as an option for their overweight and/or diabetic patients. Fat loss and insulin levels are entwined as fat loss can only occur when insulin levels are relatively low. Low levels of insulin in the blood allow the body to utilize the fat stores and ultimately burn fat for energy. Dr. Ted Naiman, MD, is a strong advocate for long fasts between meals, and claims that a fasting period of 18 to 24 hours produces the greatest drop in insulin levels and thus causes the most fat burn (Mangan). Fasting for several hours at a time will result in an overall decrease in calories consumed, resulting in fat loss.

The numerous health benefits of intermittent fasting on several biological systems. It is shown to improve cardiovascular health, brain function, and immune health, along with many other biological functions.

Intermittent fasting could have an immense impact to humans if we all underwent a change in our eating patterns. Religious fasts have been shown to improve many health markers, and scientists have empirically proven that practicers have a lower risk of obesity, diabetes, and cardiovascular disease. These conditions are quite eminent as they affect many people worldwide. As such, fasting could be the key to fixing these health problems. With the science clearly backing the diet’s proponents, it is only a matter of time until more people begin to take advantage of intermittent fasting and live longer and healthier lives.




Alirezaei, Mehrdad et al. “Short-term fasting induces profound neuronal autophagy” Autophagy vol. 6,6 (2010): 702-10.

Belman, Orli. “What to Know about Fasting, Aging, the ‘Longevity Diet’ and When You Should Eat.” USC News, USC, 16 Mar. 2018, news.usc.edu/135551/fasting-aging-dieting-and-when-you-should-eat-valter-longo/.

Glick, Danielle et al. “Autophagy: cellular and molecular mechanisms” Journal of pathology vol. 221,1 (2010): 3-12.

Mangan, P. D. “The Sweet Spot for Intermittent Fasting.” Medium.com, Medium, 12 Aug. 2016, medium.com/the-mission/the-sweet-spot-for-intermittent-fasting-9aae12a2158c.

McFarling, Usha Lee. “A Biochemist Created a Longevity Diet That Supposedly Has the Benefits of Fasting but Lets You Eat More Calories – and It Costs $300 a Box.” Business Insider, Business Insider, 15 June 2017, www.businessinsider.com/fasting-diets-valter-longo-prolon-2017-6.

Patterson, Ruth E et al. “Intermittent Fasting and Human Metabolic Health” Journal of the Academy of Nutrition and Dietetics vol. 115,8 (2015): 1203-12.Virgin, JJ. “Why Intermittent Fasting Is The Best Thing To Ever Happen To Your Metabolism.” Mindbodygreen, Mindbodygreen, 22 Jan. 2018, www.mindbodygreen.com/articles/why-intermittent-fasting-is-the-best-thing-to-ever-happen-to-your-metabolism.

Trepanowski, John F and Richard J Bloomer. “The impact of religious fasting on human health” Nutrition journal vol. 9 57. 22 Nov. 2010, doi:10.1186/1475-2891-9-57

Virgin, JJ. “Why Intermittent Fasting Is The Best Thing To Ever Happen To Your Metabolism.” Mindbodygreen, Mindbodygreen, 22 Jan. 2018, www.mindbodygreen.com/articles/why-intermittent-fasting-is-the-best-thing-to-ever-happen-to-your-metabolism.

1 Comment

  1. Thu Le

    Hi Yash, I think you post is fascinating. After reading it, I am inclined to look into this regime and the science behind it. However, I have a few questions. You say everyone should try intermittent fasting, but people may respond very differently to the same diet. While it is pretty clear that intermittent fasting helps to burn fat, what about people who already have low body fat percentage and people who want to gain muscles or weight? And would this regime have similarly positive effects on growing children who are not overweight? I am very interested in seeing more research done on how well this regime work on different demographic groups, and before that, I think we should be cautious about claims that this regime works for everyone.

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