Different Types of Fasting

  •   Danielle L’Ami

So many ways to approach fasting. Here’s a quick overview of the different types, along with sources and insights that may help you decide which is best for you.

An image of hungry woman on a diet to illustrate different types of fasting

In the United States 24% of adults have tried an intermittent fasting diet for weight loss. But what is intermittent fasting? Is it safe? Is this a promising way to lose weight or a fad diet? And are there any other health benefits? Keep reading to learn more!

Tips when considering an intermittent fasting diet:

Here are three tips to keep in mind when considering a fasting diet. First, it’s always a good idea to consult with your doctor since intermittent fasting is not appropriate for everyone. Next, when deciding between the different methods, focus on your eating and exercise habits to decide which type of fasting is practical and sustainable for your lifestyle. Lastly, just because you are on a fasting diet doesn’t mean you can eat whatever you want. It is important to make sure that you are consuming healthy and nutritious foods that will help you achieve your weight loss goals.

1. The 5:2

The first type of fasting we are going to discuss is the 5:2 which is also called the Fast Diet. This diet allows you to have five days of eating however you want and two days of restricting calories. On the two days of restricted calories, you are limited to 500 calories, 200 of which should be protein. While restricting calories on the two days you can consume the 500 calories anytime within the 24 hours.This diet also encourages you to stay well hydrated. 

This diet was popularized by British journalist Michael Mosley. They altered it slightly stating that men can consume 600 calories, while women should stick to 500 calories.

A benefit of the 5:2 method is if you like to workout you can exercise on the 5 days. A study found that fasting for 24 hours significantly increases levels of the human growth hormone (HGH). HGH is related to growth, weight loss, muscle strength, and metabolism and therefore may contribute to better weight control and weight loss. On the negative side, heavily restricting calories for 24 hours is not for everyone. If you are someone who eats frequently, you may prefer an alternative method.

2. The 16:8

The 16:8 rule requires you to restrict eating to a timeframe of 8 hours while fasting the other 16 hours of the day. Many people like this fasting method because you can fast through the night while sleeping and then skip breakfast to make it easy to complete the required hours. Within your eating window, there is no restriction on calories. While you are fasting, water or zero-calorie drinks are allowed. Unsweetened tea is a great solution here, particularly green tea, which has many health benefits as we discuss in our post on green tea.

For men looking to lose weight but maintain their muscle mass, this may be a good option. Researchers have found that men who fast for 16 hours lost more fat while maintaining muscle than those who ate normally (Moro et al., 2016). This diet can be challenging for people who prefer to have breakfast or prefer eating before an early morning workout. A possible solution to this problem could be opting for an early dinner and starting your 16-hour fast after.

3. Alternate Day Fasting

Alternate day fasting involves fasting every other day. While fasting you are restricted to eating  500 calories. This is an intense method and not recommended for people new to fasting. 

Similar to the 5:2 method, alternate day fasting forces you to limit your workout days to the days you eat. In this case, that would mean only working out four days one week and three days another, which can be difficult for some people. A study published in the JAMA National Medicine, found an alternate-day fasting diet was not superior to the daily calorie restriction diet. Researchers found no difference in adherence, weight loss or weight maintenance. 

Other Methods

Eat Stop Eat

This method was popularized by fitness expert Brad Pilon and allows the participant to fast for 24 hours once or twice per week. Similar to the 5:2 method but this fasting window means no eating whatsoever. Consuming non-calorie beverages is allowed. It also suggests that participants ease into the 24-hour fasting window; by starting with 16 hours and working their way up.

The Warrior Diet

Another method popularized by a fitness expert, Ori Hofmekler. This method restricts what you eat during the day to fruits and vegetables and allows for one large meal at night. Your large meal is restricted to a 4-hour timeframe. While on the Warrior Diet you should consume whole foods and limit processed food.

Spontaneous Meal Skipping

This method focuses on the idea that if you are not hungry, don’t eat. It goes under the assumption that our bodies are equipped to handle missing the occasional meal. It is important to mention that this method does not appear to have been studied enough. 

Benefits of Fasting

Although fasting may seem like an extreme diet method, our bodies have evolved to handle not eating for many hours, even days if needed. Mark Mattson, PhD who has studied intermittent fasting said, “Before humans learned to farm, we had to survive without food for long periods”. 

The benefits of fasting range from boosting memory to improving blood pressure and resting heart rate. (For more help improving your blood pressure, read our post on it here.) Leading longevity scientists found that intermittent fasting can also protect from age-related diseases such as Type 2 Diabetes and cardiovascular disease (Mattson, Longo & Harvie et al. 2017). Animal studies on mice have also shown that fasting mice live longer compared to mice who eat more frequently. Further research on intermittent fasting is needed to look at the long-term benefits in humans and the impact it has on younger and older healthy individuals.

Final Thoughts

There is no one size fits all approach to intermittent fasting, just like there is no quick fix to losing weight in a healthy manner. The reason that fasting diets are common for weight loss is because they strictly reduce calorie intake while reducing the time frame you can overeat. Overall, the best way to lose weight is by limiting calorie intake, exercising, reducing processed foods and staying hydrated. Recall in our water blog post, that it is important to stay hydrated. For some people that may mean following an intermittent fasting diet and for others that may mean creating their own plan which works for their lifestyle.

Danielle L’Ami

Danielle L’Ami is a logophile who writes her passion and loves to connect with others through her thoughts and personal experiences. When she is not writing, you can find her watching hockey with her husband, torturing her children with new recipes, or practicing yoga to keep herself balanced.

My Toolbox Genomics empowers individuals in their healthcare journey by creating reports focused on genetic predispositions derived from published research. Test results and suggestions are intended to lead to consultation with one’s healthcare practitioner. MyTBG reports do not diagnose disease or medical conditions. Any lifestyle changes should result from consultation with qualified healthcare practitioners.