Intermittent Fasting: What Is It, and How Does It Work?

Sydney Mulroy
Intermittent Fasting: What Is It, and How Does It Work?

Interested in learning more about Intermittent fasting? Don’t know if it’s right for you? There are many anecdotal claims from family members and friends who claim intermittent fasting have cured their health concerns. There is research to support claims such as improved glucose regulation, weight loss benefits, mental health, and even longevity. I will share research and provide you with a layout to see if this would be a good fit! 

What Is Intermittent Fasting? 

Over the last decade intermittent fasting as a health practice has become more and more common. Hunters and gatherers practiced this eating style first. Naturally it took more time and effort to acquire and prepare food. In short, periods between eating were much longer, sometimes going days without food. Due to farming and all technology advances we now can have almost instant access to food. This means the eating window has increased and the fasting window has decreased. Intermittent fasting is an eating pattern that focuses on duration of your fed and fasted states. We will dive into the specifics, however here are some benefits supported by research

  • Better glucose management 
  • Longevity 
  • Mental benefits such as reducing degenerative diseases such as dementia.
  • Weight management and potential weight loss benefits 

Please be advised, Intermittent fasting (IF) is an eating pattern that might be linked to health benefits. On the other hand, it may not be a good fit for someone with a history of disordered eating, some currently experiencing an eating disorder, or have frequent intense cravings/appetite. 

We will break down the fundamentals of the what and hows of this eating pattern. 

Intermittent fasting might be a good addition to your routine along with at-home wellness test to further optimize your health. 

Here are the basics of intermittent fasting. 

Where to Start with Intermittent Fasting?

Starting off with the definition from Merriam Webster dictionary: 

  • Intermittent =  occurring at irregular intervals; not continuous or steady 
  • Fasting= abstain from all or some kinds of food or drink 

This eating pattern in simple terms is creating parameters around when you are eating and when you are not eating. You already do this to a degree if you are not eating overnight while you're sleeping (which is common for most people.) However certain ratios of being in a fasting state vs fed state may have varying benefits. The most common 2 types of intermittent fasting you will hear people and research refer to include: 

  • 16:8, 16 hour fast and 8 hour eating window
  • 20:4, 20 hour fast and 4 hour eating window 

The benefits of having this period of fasting in your schedule allows for your blood glucose to decrease, reduces insulin production, and provides a break in your digestive tract. Another benefit of including a fasting period, it allows the body to tap into your glycogen stores (aka stored easy to access energy) and start to burn fat for fuel. The ability to use glucose and fat storage (see through ketones) for energy.

Here is how you could implement these different routines and reap the potential benefits.

The 16:8 

This fasting to eating ratio window is a less disruptive intermittent fasting schedule, therefore the most commonly practiced routine. Majority of the fasting occurs overnight while you are sleeping. A practical schedule could look like: 

  • Fasting: 6pm - 10am or 7pm - 11am or 8pm - 12pm 
  • Eating: 10am - 6pm or 11am - 6pm or 12pm - 8pm

If you are interested in balancing your blood glucose and your metabolic health, then having an earlier eating window may have additional benefits because it’s more aligned with the natural circadian rhythm when we are more insulin sensitive and digest at a more optimal rate. Along with improved digestion, there may also be gut microbiome benefits as well.
This routine is also closer to the modern western eating pattern, a sample meal timing for a 16:8 intermittent fasting schedule could look like: breakfast at 11am, lunch at 1 pm, dinner at 6pm. 

The 20:4 

This schedule of a 20 hour fast is more restrictive since the eating window is only 4 hours. It can be challenging to meet all your nutritional needs for the day and it might be a good idea to discuss with your doctor if further supplementation is recommended to meet daily needs. Also it would be highly recommended to make the meals you do consume in the eating window to be nutrient dense by incorporating high quality protein, healthy fats, and whole sources of complex carbs. 

A practical schedule could look like: 

  • Fasting: 2pm - 10am or 4pm - 12pm or 6pm - 2pm 
  • Eating: 10am - 2pm or 12pm - 4pm or 2pm - 6pm

This routine could present some challenges for many people just to list a few: anyone with active jobs, athletes or those who do strenuous workouts, have GI conditions, insulin resistance or a history of hypoglycemia. 

Intermittent fasting doesn’t mean it has to be a routine you follow each day, some people include two days of these longer fast days into their week and may still see benefits. This type of diet or new health routine are considered implementing, there is always flexibility and you can make this eating pattern individualized to your routine. 

Intermittent Fasting and Weight Loss

This focus on when you are eating is often discussed when referring to weight management or weight loss strategies. There could be a connection with intermittent fasting and weight loss because it gives your body time to deplete your energy stores and start to use stored adipose (or fat storages) to fuel all the metabolic processes in your body.  

It's also a weight loss strategy because it may reduce overall caloric intake with less guidelines compared to other methods. Since you are removing or shrinking the window of eating, there is less opportunity/time for meals and snacking, so overall intake could decrease without having to change up the “what” of your diet. This could also be beneficial for those that find themselves mindlessly eating in the evening. 

Difference for Women and Men? 

A commonly asked question when it comes to intermittent fasting, is about the difference in recommendations for women vs. men. When it comes to fasting for women, research supports 14-16 hours could be a fine fasting period for women. However, over 16 hours of fasting may result in a stress response in women. The increase in stress hormones can alter insulin sensitivity in a way that could have a negative impact on overall health. However this doesn’t not hold true for men. There is less research that indicates fast over 18 or even extended fast in moderation have negative effects for men.

What to Consider for Starting? 

Before starting any new eating routine, it is important to check with your doctor to see if it would be a good fit, your doctor can consider your health history and conditions to help you determine if intermittent fasting could be valuable for you. 

Also factor in what you plan on breaking your fast with and your meals during your eating window. While this eating pattern doesn’t have recommendations for the what in your meals, having high quality meals planned ahead can help you meet your nutritional goals during the shorten eating period. 

The long term efficiency of intermittent fasting for weight loss is still up for debate. More research is needed but some has shown reversed results if intermittent fasting is not continued after the weight loss phase and practiced as a daily habit in weight maintenance. With any change in your diet or lifestyle habits, if you don’t see yourself being able to maintain it for the next 5-10 years, then it probably is not a realistic approach to improving your health for the long term.


Intermittent fasting is more than a trendy diet, it now has research to back some potential health benefits. If you are looking to optimize your routine and health, intermittent fasting could be a perfect pair to your Vessel at home wellness test. Testing your urine for and getting your wellness score is a great way to bring intention to your health goals for the day and set you up for a health minded week.