The Do's and Don'ts of Intermittent Fasting - Blog - Persona Nutrition

The Do’s and Don’ts of Intermittent Fasting

As intermittent fasting becomes more and more popular, have you ever wondered why it seems everyone follows it a little differently? Intermittent fasting can in fact vary in the way that it is practiced and can be modified to best fit your lifestyle. However, there are some important tips to remember to ensure you are following it properly.


What is Intermittent Fasting?

Intermittent fasting is not necessarily a “diet” but more so a way of eating. Intermittent fasting is defined as rotating between periods of fasting where you consume no food or any form of calories and periods of feeding where you consume food.1 Individuals can follow the fasting portion in a variety of different ways. Alternate day fasting involves fasting for an entire day and eating normally for an entire day. Another method is the 5:2 fast which consists of restricting calories for two days and eating normally for the other five days. The other option is to eat following a time-restricted schedule.

Time-restricted fasting is the most common form of intermittent fasting, and it involves spending a certain amount of time each day in a window of fasting and eating. Common fasting and eating windows include a fasting window of 16 hours and an eating window of 8 hours and a fasting window of 14 hours and an eating window of 10 hours.2


Benefits of Intermittent Fasting

Intermittent fasting is continually being researched and may have several benefits as it pertains to weight loss, improving health parameters, and longevity.3 Intermittent fasting can be a beneficial tool for weight loss as it may be easier to maintain a calorie deficit while still feeling satiated. Intermittent fasting can also help to improve insulin sensitivity, which means the body can use glucose more effectively.3 Intermittent fasting may also play a role in aging as some evidence suggests reduced oxidative stress and inflammation (as the two are closely related) and can even help to preserve memory.3

Does it seem too good to be true? With the seemingly endless benefits, who wouldn’t want to follow intermittent fasting? It does take discipline and may not be the best fit for all lifestyles. Here are some key points to keep in mind when intermittent fasting:


  1. Continue to consume around the same amount of calories as you would if you were not fasting. The goal with intermittent fasting is not to slash your calorie count and completely skip meals, but instead to shorten the time frame in which you are consuming these calories.
  2. Plan meals that are nutrient-dense to provide you with the energy that you need to thrive. After fasting for 14-16 hours, it is crucial that the first meal you consume contains high-quality protein and healthy fats to nourish your body properly.
  3. Consume plenty of water and feel free to incorporate any zero-calorie beverages such as black coffee and unsweetened tea into your diet. Be mindful not to add any cream, milk, or sweeteners to coffee and tea as these do contain calories and can break your fast.
  4. Wait to take your supplements with your first meal. Supplements are best absorbed when taken with food as many vitamins and minerals are fat-soluble and need dietary fat for best absorption.
  5. If you do want to workout shortly before breaking your fast, consider supplementing with a BCAA which can help maintain lean body mass.



  1. Begin intermittent fasting too quickly. It is okay if you want to try a longer feeding window and a shorter fasting time before transitioning to the more traditional fasting time periods of 14/10 or 16/8.
  2. Be careful not to eat such a large meal when first breaking your fast for the day. This can contribute to digestive discomfort and may make it difficult to consume the rest of your meals throughout the day.
  3. Do not follow intermittent fasting or any sort of time-restricted eating if you have any history of or currently have disordered eating, an eating disorder, hormonal irregularities, or are trying to get pregnant.
  4. Do not complete a vigorous workout hours before breaking your fast. It is important to fuel yourself properly around your workouts and waiting too long to eat can leave you feeling extremely fatigued.
  5. Do not wait to take medications if you must take them at a specific time of the day with food. Please discuss with your doctor if you take prescription medications or have any other health conditions that may impact your ability to intermittent fast.
  6. Do not continue to follow this way of eating if it does not benefit you. Intermittent fasting should only be a diet tool that can positively benefit your life, and it results in any negative side effects, continuous fatigue, or impacts your relationship with food, it is likely not beneficial for you.


Take-Home Message

Intermittent fasting is not the answer to all your health concerns. It is not a magical way of eating that makes you lose weight overnight. Intermittent fasting may be a useful approach to aid in weight loss efforts or improve your overall health. If you are in good physical health and you have a healthy relationship with food, feel free to try it and see if intermittent fasting can benefit you!


  1. Diet Review: Intermittent Fasting for Weight Loss. The Nutrition Source. Published May 22, 2019. Accessed November 10, 2020.
  2. Grant M. Tinsley, Paul M. La Bounty, Effects of intermittent fasting on body composition and clinical health markers in humans, Nutrition Reviews, Volume 73, Issue 10, October 2015, Pages 661–674,
  3. Harvie M, Howell A. 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. Behav Sci (Basel). 2017;7(1):4. Published 2017 Jan 19. doi:10.3390/bs7010004

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