What is Intermittent Fasting? | Can I combine Intermittent Fasting with the Keto Diet?

Did you know that the improper management of blood sugar levels can cause stress? When hungry, we often grab the easiest option which usually ends up being a quick-fix to feel better and allow us to continue on with the task at hand. As a result, an hour, maybe two later the process repeats itself as our blood sugar dips again due to the lack of sustenance.  

There are a number of ways this can be remedied, most commonly by analysing the foods you consume to reduce simple or processed carbohydrates, another way would be to address your feeding window to find the most optimal times to eat. As your schedule gets busier, does the time for proper eating become less of a priority? Perhaps, incorporating a different approach to your eating habits could be of great benefit. 

Balance your diet through Intermittent Fasting 

balance your diet swiss point of care

Intermittent Fasting (IF) is a dieting choice that controls when you are allowed to eat. Fasting refers to the period of time where you are not feeding yourself, which is also where the term breakfast originates—breaking your fast! With intermittent fasting, you will spend the majority of your day in a fasted state and only eat within a predetermined time frame, usually eight hours¹. For example, during the hours 12:00 to 20:00 you will eat and enter the fasted state for the other 16 hours. This form of eating shares similar fat-burning advantages to those found on the ketogenic diet, where, by periodically fasting there is a trigger to change the metabolic process to the alternative fuel source, ketones.  

Accessing our fat stores heavily depend on the energy balance within our bodies. What this means is that in order to burn off our excess fat stores, we need to be burning more calories than we are consuming. When we enter into a fasted state, the body is no longer receiving external calories and is therefore forced to use the existing fat stores for energy². 

Different Fasting Strategies 

Intermittent fasting comes with a lot of flexibility in how you choose to execute your time frames. This ranges from whole-day fasts to alternate-day fasts and the more popular, time-restricted daily fasts³ ⁴. 

  1. Whole-day fasts take place 1-2 days a week where your calorie consumption does not exceed 25% of your daily calorie requirements, whilst having no food restriction for the other 5-6 days. An example of this would be the 5:2 approach, which includes 5 regular days of eating, followed by 2 days restricted to 400-600kcal each day. 
  2. Alternate-day fasts take place every other day. For example: Mon-Wed-Fri will be the fasted with calories restricted to 25% of the daily calorie needs, and Tue-Thurs-Weekend will include no calorie restriction. 
  3. Time-restricted fasts take place daily within a given time frame. The most common example is the 16:8 approach, where meals are eaten within an 8 hour window and you remain fasted for the other 16. For beginners⁵ who want to enter into this regime, starting with a fast of 12:12 (equal hours fasted to regular eating) might be easier as the fasting window is relatively small and most of it takes place during the sleeping windows.

There are however several other approaches to fasting, some of which include 24-hour fasts or 1-meal-a-day fasts. Notably though there is no single plan that is designed to work for everyone. As we all lead drastically different lives, you can find the right approach for you. Learning to incorporate intermittent fasting to your eating habits comes with a number of health benefits including learning how to control how your body responds to hunger. 

Benefits of Intermittent Fasting 

keto balancing your diet swiss point of care

Incorporating IF into your lifestyle provides you with more benefits than just burning fat. It helps your body develop a metabolic switch between burning glucose and ketones for energy. Some other benefits include⁶: 

  • Reduced cell damage from oxidation and inflammation 
  • Lowered blood sugar to better control diabetes 
  • Improved memory 
  • Reduced belly fat and lowed blood pressure, both of which contribute significantly to heart disease 
  • Lowered risk of cancers 
  • Aids in the recovery from surgery 

One of the main benefits to intermittent fasting is weight loss as the restriction of food intake throughout the day alleviates some of the stress from the pancreas. When we consume calories, our bodies break down the foods into glucose, which in combination with insulin, enters our cells for either energy or storage. During the fasting windows our insulin levels drop⁷ and once they are low enough, our bodies release triglycerides stored in our fat cells for energy instead.  

Intermittent Fasting and the Ketogenic Diet 

Intermittent fasting can be used in conjunction with the ketogenic diet to help facilitate getting into ketosis faster. For your body to enter ketosis, you need to be in a state where carbohydrate consumption is extremely low, or when you are in a fasted stage. Therefore, intermittent fasting can help you to deplete your glucose stores at a much faster rate⁸, speeding up the transition to ketosis.

keto balance your diet swiss point of care

When combining the ketogenic diet with IF, it’s important to note that fasting is not enough to keep you in ketosis. Just eating even a moderate amount of carbohydrates will be enough to cause your body to revert to burning glucose again. The ketogenic diet does however help in establishing keto-adaptation, an element of fat-adaptation⁹, where your body will acclimate to using ketones as its primary fuel source instead of glucose. The benefit of becoming keto-adapted is that unlike glucose, ketone bodies are more energy intensive, meaning that a keto-centred metabolism could potentially provide a more consistent energy supply. What this means is that you will feel sustained for longer, when fuelling your body with keto-rich foods. 

Who should be cautious with fasting? 

As with any eating lifestyle, sudden changes should be done with careful consideration, in particular⁴ ⁵ ¹⁰: 

  • Women who are pregnant or breastfeeding 
  • People with health conditions, such as diabetes or blood sugar problems 
  • People with eating disorders (anorexia and bulimia) 

If you have underlying health conditions and are looking to start with a different eating regime, it’s best to approach with caution. Do your own research into the topic and then consult a professional for advice. 

Medical Disclaimer: The information reflected in this article is intended for educational purposes only. Please consult your physician or medical specialist before making any major adjustments to your diet. 

References 

  1. Harvard Health Publishing (2020) – Time to try intermittent fasting, published by Harvard Medical School. 
  2. Rosly, R (2021) – Intermittent Fasting vs Keto Diet for Weight Loss, published by UM Specialist Centre. 
  3. Harvard TH Chan (2021) – Diet Review: Intermittent Fasting for Weight Loss, published by the School of Public Health. 
  4. Johns Hopkins Medicine (2021) – Intermittent Fasting: What is it, and how does it work? 
  5. Leonard, J (2020) – Seven Ways to do intermittent Fasting, published to Medical News Today. 
  6. UCI Health (2020) – The Benefits of Intermittent Fasting, regent of the University of California. 
  7. Tello, M (2020) – Intermittent Fasting: Surprising Update, published by Harvard Medical School. 
  8. Godinez, B (2021) – The Complete Guide to Intermittent Fasting 16/8. 
  9. Ma, S and Suzuki, K (2019) – Keto-Adaptation and Endurance Exercise Capacity, Fatigue Recovery, and Exercise Induced Muscle and Organ Damage Prevention: A Narrative Review. 
  10. Gleeson, J (2019) – Intermittent Fasting: Is it Right for You? Published by Michigan Health. 

Read More