Yes, this will be a very informative article that looks at intermittent fasting from an objective point of view. No, we can’t tell you if this is an eating style that you should pursue unless you are an Arrow client.
The biggest takeaway I hope you experience from this read is that it provides an evidence-based look at intermittent fasting. What the evidence tells us is that we need MORE evidence before we can come to any conclusive answers.
Intermittent fasting is a type of eating that cycles between periods of fasting and periods of eating on a very specific schedule. Individuals who participate in intermittent fasting tend to fast for a certain number of hours per day and leave themselves a small window of time to eat their required food intake at once. Some use this style of eating as a way to achieve weight loss while others may use intermittent fasting for health reasons due to a small amount of research that has shown it may be beneficial for treating or preventing some forms of disease.
In order to see intermittent fasting from an objective point of view, we must identify the good and the bad that goes along with this style of eating in order to decide if it might be right for our individual needs. Is there any evidence to support the claims that intermittent fasting provides health any health benefits? Some bodies are research say it’s possible. In a 2017 review done by Patterson and Sears, they found that “modified fasting regimens appear to promote weight loss and may improve metabolic health.” During this review, they also found that intermittent fasting may prevent nighttime eating which can be a hard habit to break for a lot of individuals. The evidence showed that one single instance of fasting had an impact on basal concentrations of biomarkers commonly associated with chronic disease, like insulin and glucose. In regard to cardiovascular health, a 2019 study done by Malinowski et al found that intermittent fasting can reduce the concentration of total cholesterol, triglycerides, and LDL cholesterol. This is primarily due the lack of regular eating intervals where the body has periodic access to glucose for fuel. During the stages of fasting, the body begins to use ketones for fuel which can decrease body mass and influence the body’s lipid profile. This study also saw a positive impact on the development of atherosclerosis where plaque development was reduced due to a decrease in inflammatory markers.
Intermittent fasting has also been shown to be beneficial in the prevention of hypertension and shown a reduction in body mass for those with obesity and di
abetes. However, the study was inconclusive over whether the mechanisms by which these individuals who saw benefits was due to the eating strategy or just a result of overall weight loss. While these studies clearly show the benefits of intermittent fasting, other studies have weighed intermittent fasting, or intermittent energy restriction, versus continuous energy restriction, commonly referred to as a calorie deficit to see if the benefits were similar. In a 2017 study done by Harvie and Howell, their evidence showed that there didn’t seem to be much difference between the benefits of intermittent fasting and continue energy restriction when it came to a reduction in body fat. For individuals with a normal weight range, they found there to be a possibility of harm utilizing intermittent fasting due to the induction of lipolysis, or the breakdown of fats, and changes in free fatty acids. These changes in free fatty acids could result in skeletal muscle insulin re
sistance which would not otherwise be seen in a generally healthy individual of normal weight. Intermittent fasting has been thrown around as a tool that may benefit athletic performance. However, a 2019 article by Levy and Chu found that intermittent fasting showed no improvement for athletic performance of any kind. Most athletic performance relies on the availability of glucose in the blood and glycogen stores in the muscle and liver. Without this energy, overall performance may suffer. With intermittent fasting, due to prolonged periods of not eating, energy stores may be depleted and there may be a lack of glucose in the blood. This article concluded that further studies were necessary for results to be conclusive.
While intermittent fasting may provide some metabolic health benefits but when weighed against continuous energy restriction, there don’t seem to be many notable benefits. For there to be true clinical relevance, many of the available studies must be done on a larger and longer scale to find more conclusive answers. Intermittent fasting may work well for some individuals and be a sustainable eating strategy to follow while not being the best choice for other individuals. The way one chooses to eat should be a strategy they can sustain long-term. It should include a nutrient-dense diet high in fiber that consists of lean proteins, fruits, vegetables, legumes, nuts, seeds, and healthy dietary fat. It should complement lifestyle factors such as physical activity, recovery from activity, and overall stress management. For those who are able to achieve these things with intermittent fasting, this may be an eating strategy that works best for them. For others, eating more regularly throughout the day while still maintaining overall energy restriction if warranted for their health might be a better strategy to be followed.
Regardless of the strategy that may work best, intermittent fasting is not recommended for children and teens under 18, women who are pregnant or breastfeeding, individuals with blood sugar disorders, or those with a history of eating disorders as it may have negative ramifications on one’s relationship with food and their body.
1. Harvie, M., & Howell, A. (2017). Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence. Behavioral Sciences, 7(1), 4. https://doi.org/10.3390/bs7010004
2. Intermittent Fasting: What is it, and how does it work? (n.d.). Retrieved October 7, 2021, from https://www.hopkinsmedicine.org/health/wellness-and-prevention/intermittent-fasting-what-is-it- and-how-does-it-work
3. Levy, E., & Chu, T. (2019). Intermittent Fasting and Its Effects on Athletic Performance: A Review. Current Sports Medicine Reports, 18(7), 266–269. https://doi.org/10.1249/JSR.0000000000000614
4. Malinowski, B., Zalewska, K., Węsierska, A., Sokołowska, M. M., Socha, M., Liczner, G., Pawlak-Osińska, K., & Wiciński, M. (2019). Intermittent Fasting in Cardiovascular Disorders—An Overview. Nutrients, 11(3), 673. https://doi.org/10.3390/nu11030673
5. Patterson, R. E., & Sears, D. D. (2017). Metabolic Effects of Intermittent Fasting. Annual Review of Nutrition, 37(1), 371–393. https://doi.org/10.1146/annurev-nutr-071816-064634