Results From My Five Day "Water Fasting" Experiment

Results From My Five Day "Water Fasting" Experiment

Updated: Apr 22, 2024Kalle Kortelainen

Calorie restriction and fasting are probably the two most tested methods to increase the health span and prevent premature ageing. We can observe this in some of the Blue Zones (i.e. Ikaria) where people fast regularly all year round. I like to experience things myself before I talk about them, so I decided to give it a try!

Defined as voluntary abstinence of all caloric foods and beverages, fasting has been practised by humans for at least 2000 years for many different reasons. What got me interested was research in animals and humans that uncovered several potentially health-promoting physiologic responses to fasting including ketogenesis, hormone modulation, reduced oxidative stress and inflammation, and increased stress resistance, lipolysis (the breakdown of fats and other lipids), and autophagy (cleaning out damaged cells, in order to regenerate newer, healthier cells).

What are the benefits of water fasting?

According to numerous clinical studies, other significant physiological benefits of water only fasting include improvements in chronic diseases such as hypertension, metabolic disease, cardiovascular disease, rheumatoid arthritis, osteoarthritis, chronic pain, and fibromyalgia. Furthermore, research indicates that fasting potentially improves the response of tumour cells to chemotherapy by repairing DNA damage in normal tissues (but not tumour cells) and by up-regulating autophagy flux as a protection against damage to organelles and some cancer cells. 

I started researching to practice a regular water only fast, 5-7 days every four to six months to prevent premature ageing and to stay fit and healthy my entire life. I studied how to prepare before the fast and how to re-feed afterwards. I was ready. The only thing I was concerned about was any unwanted change in my body composition. It took me over six months to gain 1.5 kilograms of lean muscle and 1% of body fat, so I was worried about losing my hard-earned gains as I’m still slightly low weight and quite lean. 

Because I don’t like guessing, I decided to measure my body composition at Body and Bone DEXA Clinic, a day before and a day after the 5-day water-only fast. Science literature suggests that in the absence of any physical activity the body conserves lean muscle mass and uses predominantly muscle glycogen and visceral fat. Because my goal was autophagy and healing, not weight loss, I planned to do absolutely no physical activity and just rest (both physically and mentally) throughout the fast. I rented a house in a national park with two friends for two different reasons: to remove ourselves from our regular environment and all its temptations (i.e. cafes on every corner) and to support each other.

The body composition results were exactly what I expected. I haven’t lost much weight at all, my 1.026kg loss in lean muscle mass was most likely due to muscle glycogen depletion and water loss. Every gram of muscle glycogen binds three grams of water. According to calculations, my muscle glycogen plus water would weigh anywhere between 1-1.4kg. I’ve lost some body fat but most of it was visceral fat and not the fat under the skin. Excess visceral fat increases the risk of various chronic diseases such as metabolic disease, cardiovascular disease, type 2 diabetes, colorectal cancer, breast cancer, and Alzheimer’s disease. That’s one of the reasons why water-only fasting is effective in chronic disease prevention and management. 

My Body Composition Results (DEXA)

Weight (kg)

Before: 52.531
After: 51.505
Difference: - 1.026 kg

Total lean mass (kg)

Before: 41.175
After: 40.351
Difference: -0.824 kg

Total fat (kg)

Before: 8.446
After: 8.271
Difference: - 0.175 kg 

Visceral adipose tissue (g)

Before: 45.1
After: 7.5
Difference: - 37.6 g 

Subcutaneous adipose tissue (cm3)

Before: 29.6
After: 24.9
Difference: - 4.7 cm3

Total fat %

Before: 16.1
After: 16.1
Difference: 0 

My conclusions about water fasting

Based on my body composition results and on the way I feel weeks after this experiment, I have decided to make it a biannual practice. I’m currently full of energy and free of some nasty symptoms I was dealing with pre-fast such as unexplained water retention, gut issues, sciatica, fatigue, and brain fog. For the first time in my life, I quit coffee for a whole month and actually feeling more energetic and alert than when I was drinking three strong coffees a day. I must admit though, that the two-week-long preparation and the week of re-feeding must have a lot to do with the way I feel. It was a whole month free from coffee, alcohol, sugar, and any processed foods whatsoever.

Remember, fasting is a part of a healthy lifestyle. If you smoke, drink alcohol, stress, don’t sleep, and eat processed foods and sugar in excess, five day water fast twice a year is not going to save you from the negative effects of such habits.



Veronika Larisova 
Co-founder, Nutritionist, Exercise Physiologist




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