Intermittent Fasting Guidance For Patients


Weight loss guidance is one of the most typical requests you may receive from your patients. With obesity and overweight on the rise and estimated to become a reality for 50% of Americans by 2030,1 it becomes crucial to give patients the tools they need to achieve a healthy weight. Diet and exercise are the gold standards for accomplishing this, but there is also a time-proven method to switch the body from burning glucose to using fat that can help patients lose weight and more--intermittent fasting.

Instead of counting and cutting calories, as is typically done on a diet, intermittent fasting approaches the window of time when one eats as a way to achieve weight management. By placing a restriction on the time when eating occurs, similar biological pathways as caloric restriction are triggered.2 The amount of time may be as little as 12 hours overnight, or for days wherein no or few calories are consumed. By doing so, metabolism is switched from glucose to fatty acid-derived ketones to preserve muscle mass and function.2 It is suggested that intermittent fasting practices may also optimize physiological function, as well as enhance performance and even slow the processes of aging and disease.2


Typical patterns of intermittent fasting 


There are several protocols of intermittent fasting that may be followed: 



This protocol encompasses five days of eating, with two days of consuming roughly 500 or less calories. 


12-hour Method 

A fast of 12 hours occurs overnight. An example of this is the last meal of the day is finished at 6 PM, and no calories are consumed until after 6 AM.


16/8 Method

Fasting lasts between 14 to 16 hours, and allows meals within an eight-hour window. Two to three meals can usually be consumed within this time period.


Warrior Fast

The fast lasts throughout the day, with a large meal consumed at dinner within a four-hour window.


24-hour Fast

A full, 24-hour fast is observed once or twice a week, with normal meals on the non-fasting days.


While research of intermittent fasting is ongoing, it is known that it can provide a flexible tool for patients who wish to achieve successful long-term weight loss and maintenance. Patients may at first balk at the suggestion of fasting, but because it can be done in various ways to meet individual needs, it may become more appealing. In particular, because the goal with intermittent fasting is not to cut calories, patients may be more compliant with this approach.





Anton SD, Moehl K, Donahoo WT, Marosi K, Lee SA, Mainous AG, et al. Flipping the metabolic switch: understanding and applying the health benefits of fasting. Obesity (Silver Spring). 2018 Feb;26(2):254-268.


Wang YC, McPherson K, Marsh T, Gortmaker SL, Brown M. Health and economic burden of the projected obesity trends in the USA and the UK. Lancet. 2011;378:815-25.