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The benefits and considerations of 36-hour fasts

by | Mar 4, 2024 | Health Tips, Nutrition Advice

In recent years, fasting has surged in popularity as a health and weight management strategy, with various protocols offering promising benefits for mental clarity, weight loss, and overall health improvement. Among these, the 36-hour fast stands out as a method that strikes a balance between challenge and feasibility, attracting attention for its potential to reset the body’s systems and offer significant health benefits. As some of you know, I started the year by trying out a couple of 36-hour fasts and with the questions it arose, I thought, why not write an article on the topic.


Understanding fasting

Fasting, the voluntary abstinence from food and drinks containing calories, has been practiced for centuries, rooted in both cultural traditions and medical recommendations. Modern fasting protocols vary in duration and rules, ranging from intermittent fasting, which alternates between eating and fasting periods within a day (5:2 diet or the 16:8 diet are popular mainstream examples), to extended fasts lasting several days. These practices are unified by their promise to aid in weight management, enhance metabolic health, and potentially extend lifespan.

The 36-hour fast

The 36-hour fast involves a complete break from calorie intake for a day and a half, allowing only water, although sometimes non-caloric beverages like black coffee and tea are included but for a true 36-hour fast with all of the benefits, water alone should be the order of the day. This period of fasting begins after the last meal of one day and extends all the way through the next day, ending with breakfast on the following day. In some ways, personally, I found this protocol to be slightly easier, psychologically, to handle as you can just rule out food completely for a day, as opposed to a 24-hour fast which invariably means dinner to dinner. In the 24-hour fasts, it means you are counting down all day until you can break the fast, so food crosses your mind more often. A 36-hour fast is designed to push the body into a state where it burns stored fat for energy, promoting weight loss, improving insulin sensitivity, and initiating cellular repair processes like autophagy. Autophagy involves removing damaged cellular components, and as such can prevent the accumulation of toxic substances within cells, thereby contributing to cellular repair and homeostasis. It’s also been linked to disease prevention, including neurodegenerative diseases, cancer, and cardiovascular diseases.

Who benefits?

Individuals looking to lose weight, improve metabolic health, and seek mental clarity may find the 36-hour fast particularly beneficial. The practice can enhance insulin sensitivity, making it a potentially effective strategy for those at risk of type 2 diabetes. Moreover, the boost in growth hormone production and the promotion of autophagy contribute to fat loss, muscle maintenance, and cellular renewal, respectively.


The array of benefits

Adopting a 36-hour fasting protocol can lead to significant health improvements, including weight and body fat reduction, heightened brain function, and improved heart health by lowering risk factors for cardiovascular disease. Furthermore, participants often report experiencing a profound sense of mental clarity and emotional well-being during and after fasting periods.


When fasting might not be suitable

However, a 36-hour fast is not appropriate for everyone. Children, pregnant and breastfeeding women, individuals with diabetes or those with a history of eating disorders, should avoid prolonged fasting. It’s also not recommended for people with certain medical conditions, those taking specific medications requiring food intake, older adults, and individuals who are underweight or malnourished.


Concluding thoughts

The 36-hour fast offers a compelling blend of challenge and reward, promising significant health benefits for those who can safely adopt it into their lifestyle. Increasingly it is appearing that for true sustainable weight loss and improvements to relationships with food, fasting is becoming the most attractive option. As previously discussed, for health purposes, it’s not an approach that will be suitable for everyone. But for those who like to explore with their health, finding the ways to optimise their well-being, I’m an advocate for the ‘give it a try’ approach and see what you think.

It won’t be a magic bullet on its own. Your weight loss will predominantly be down to water weight. But if you consider that your body is an engine that is constantly working throughout the day, fasting gives you a brief window to let certain bodily actions relax, reset and potentially be better once you get them up and running once more.



Personal trainer, and fitness writer, editor and author. Darren is the founder of Dynamic Fitness Training, a personal training company based in north London.