What If You’re Not Just WHAT You Eat, But Also WHEN You Eat? 


The Science and Benefits of Fasting

Jessica Maloh ND, Raja Sivamani MD MS AP

The practice of fasting dates back centuries in various religions and philosophies around the world. Traditionally, fasting has been used as a tool to aid in redirecting attention, and as both a spiritual and physical cleanse or reset. In Ayurvedic medicine (from India) fasting is used to give your digestive system a rest and reinvigorate mental, digestive, and physical energy.  

In more recent years, increasing scientific research is demonstrating that the benefits transcend spirituality to also affect the body and mind. For example, emerging evidence points to decreased inflammation, protection against oxidative stress, lower body fat, improved cognition, and increased lifespan. 

To reap these benefits, it is important to understand the various fasting protocols that have been studied and to work alongside a health care professional that can help you follow the best-suited and safest fasting method for you. 

The 16:8 Method

This fasting approach can be referred to as “time-restricted feeding.” You can set the timing to what is most convenient for your schedule, allowing for an 8-hour eating window, and a 16-hour fasting window. For example, if you set your dinner time for 6 pm, the next eating period would begin 16 hours later, at 10 am on the next day. No caloric restriction is involved with this approach.  A simple way to think of this method is to eat an early wholesome dinner and then enjoy a healthy brunch the next day. 

The 5:2 Method

With the 5:2 method, there will be 5 days of the week that you select that will not require fasting or modifications to your normal mealtimes. On the remaining 2 days of the week, however, caloric intake will be reduced to 500 calories for women and 600 calories for men. 

Alternate Day Fasting

As the name implies, this approach includes fasting every other day, where the fasting days consist of caloric restriction. The instruction on fasting days is to limit calories to 25% of normal intake, which would be approximately 500 calories. 

Pseudo-Fasting Method

New protocols are being developed to mimic the effects of fasting on the body with carefully thought-out meal plans. Here, the meals are developed with specific macronutrient profiles and with short-term caloric restrictions. Unlike the previous fasting approaches that are meant to be practiced long-term, this method requires only 5 days of the month and is recommended for 3 cycles. 

Emerging research suggests that these examples of time-restricted and/or calorie-restricted fasting protocols can lead to a longer lifespan, a leaner physique, and a clearer mind…but what is the underlying mechanism? 

There are several explanations for the benefits of fasting. One explanation is “autophagy,” which can be thought of as self-cleaning. In the absence of food, the body can clean out damaged or dysfunctional cells and cellular components. This may help in putting a stop to troublesome or inflammatory pathways in the body. 

Other proposed explanations include a shift in metabolism to allow for more fat burning, shifts in the gut microbiome, and one explanation that we would be very interested in exploring would be the shift towards more mindful eating that may potentially come with fasting. 

Nevertheless, from a scientific perspective and a holistic perspective, it seems that health is not only related to what we eat but also when we eat and that different forms of fasting when done appropriately may help us optimize our state of health and wellness.

RAJA SIVAMANI-Dermatology-CA-Zen Dermatology



I am a native of the San Francisco Bay Area and a board certified Dermatologist. My expertise centers on general dermatology including medical, surgical, and cosmetic services. With training in bioengineering, Allopathic and Ayurvedic medicine, I merge modern research and science with a personalized approach to each patient. My training in Ayurvedic medicine lets me bring in a more humanistic approach to my patient care, science, and research.

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