Friday, October 19, 2018

Intermittent Fasting and Weight-Loss: A Cause for Concern or Celebration?


     With all of the praise that fad diets receive in the media, it is easy to overlook the consequences that they may have on the body. While scientists have proven that some programs are a healthy and effective tool for weight-management, others remain unchallenged and their potential risks remain unexamined. Within the last few years, lifestyles like intermittent fasting have become more popular than well-known fad diets like Nutrisystem and South Beach Diet. Intermittent fasting is characterized by alternating periods of normal caloric intake and fasting. While it provides its participants with many benefits, there is still a lot to learn about it, leaving me concerned about potentially adverse effects on the body. Specifically, I am concerned about its effect on the circadian rhythms of the body and will address my concerns in this post using research on the feeding behavior of Drosophila melanogaster.
First, I will explain how food intake is connected to circadian rhythms – a biological clock in the body that is primarily controlled by periods of light and dark – using research on Drosophila melanogaster, or fruit flies. Researcher Austin Dreyer with Loyola University Chicago studies how the feeding behavior of fruit flies adheres to circadian rhythms. Because Dreyer has not yet published this work, I will summarize the results of research that is similar to that of Dreyer’s. Xu, Zheng, and Sehgal (2008) studied how the feeding behavior of fruit flies relies on both neuronal and metabolic clocks. In their work, Xu et al. (2008) found that metabolic clocks located in digestive tissues and fat bodies regulates feeding rhythm. Flies that lack clocks in these tissues exhibited peaks in feeding that started late in the cycle and lasted until the next day, which is the opposite of normal feeding behavior; normal feeding behavior follows a 12:12 pattern of light-dark cycles in which the flies feed early in the cycle. More importantly, the researchers found that disrupted metabolic clocks leads to a deficiency in energy storage and metabolism in the fat body and an increase in food intake. As a result, the flies were less resistant to starvation.  
According to Markham Heid in his article “What Is Intermittent Fasting and Is It Actually Good for You,” intermittent fasting promotes “sustainable weight-loss” as well as provides many health benefits to its participants like “protection from diabetes, heart disease, and cancer.” As research continues on the subject, the list of benefits continues to grow. However, Heid fails to mention the risks of participating in intermittent fasting, which, to me, suggests that researchers have not yet found any risks. This is where the fruit-flies come into play. Although fruit flies do not look remotely similar to mammals – or humans – their bodies perform similar processes to those of humans using analogous structures. Remember how I told you that the fat body of fruit flies is responsible for energy storage and metabolism? Well, the mammalian liver does the same thing (Xu, Xheng, & Sehgal, 2008). Like I said before, Xu et al. (2008) found that interrupted clocks alter food intake, and, as a result, the body cannot control energy metabolism or storage, making the flies less resistant to starvation. In the case of intermittent fasting, I am concerned that altering food intake would alter the way that the metabolic clocks function in humans, causing the body to lose control of energy metabolism. In other words, does intermittent fasting alter the circadian rhythms of the body? Are these changes detrimental, or will the body adapt over time? Although intermittent fasting provides participants with many health benefits, I think that the cellular effects of intermittent fasting should be investigated using fruit flies in order to determine whether it is actually beneficial to the body.


Xu, K., Zheng, X., Sehgal, A., (2008). Regulation of Feeding and Metabolism by neuronal and peripheral clocks in Drosophila. Cell Metabolism, 8, 289-300.

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