The 72 hours fasting experience.

The 72 hours fasting experience.

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I’ve been reading for years now about of intermittent fasting strategies and the several health benefits related to it. I have played with the 16/8hours – 16 hours fasting window / right after dinner until 12pm or 2pm the next day depending of the time of dinner, for a long time I felt great applying this strategy and I still believe is the best way to keep healthy, lean, strong, happy & productive as a lifestyle  and often I’ve tried the eating once a day strategy in days that I was completely occupied doing what I love which I get to call work.

Often on the studies, seminars, podcasts and articles I am interested in I would find some practitioners which would recommend longer fasting periods once in a while (once every 3 months) but I was always reluctant to try due to the fact I was convinced I would lose muscle mass so I’ve chosen to believe the strategy for me would be the 16/8 and that was it with fasting.

A few weeks ago me and Andreia (my Wife Dietitian) we are reading this website which we found about some really interesting supplements and the owner of this company was given his take on fasting for 3 to 5 days within the 3 months window between a bunch of other cool elements which I also advocate like cold therapy strategies, eating real food and training hard. So I’ve decided I would do a 3 days fast as I wanted to experience how it would be for the mental challenge component, I’ve decide I would enjoy the 3 days and as with anything else in life that I decide and commit to it, considered done…

Day 1

Not any difference  than any other eating at night time day, the only thing I’ve missed quite a bit was my morning black coffee, other than that cruising all the way to dinner time. I have to admit that having my wife on my corner helped big time, she didn’t cooked any delicious dinner for herself in fact she did ate at a different times throughout the entire 72hours. Yes, the 72hours is just with water… 

Day 2 

During my normal morning rituals I’ve felt great but later mid morning I felt a bit tired with different energy levels I normally experience. I believe my body was really depleting all glucose available before kicking in nutritional ketosis and by the mid afternoon I’ve started to feel the energy kicking back in, I could really sustain the same felling of no hunger or desire for food all the way to dinner time, I must say that at this stage it weirdly felt comfortable and for me to say that is big statement simply because I am big eater but yeah I could easily see myself finishing the 72 hours with no worries at all.

Day 3

Why not trow a workout in and see what happens!

Train a few clients in the morning about 15 sessions, had a gap in my the diary so I’ve decided to have a workout I was really intrigued in regards my performance and how I would feel. I did a back and chest split routine in 20 minutes which is all it takes at Intense Health, I felt incredibly good throughout that workout and have got some great quantification over that workout, not my PB over all but really good force output and surprised elevated energy levels, ketones were definitely up & high at this stage. What was really fascinating was that after the workout I felt even better and that great feeling lasted all the way to the end of a normal 14hours Wednesday day where it has finished with a great new client starting his journey at Intense Health, I really felt like going for 5 days, the only factor that hold me back was that I was so curious in how my body was reacting without food for 72 hours so I’ve decided to do the measurements and next time I might go for 5 days fasting as a new challenge.



Body composition measurements:

Sunday 06/05 night measurements (Start) Wednesday 09/05 night measurements (Finish)
Body weight: 94.4kg.  Body weight: 90.2kg
Chest: 115cm Chest: 113cm
Abdominal: 95cm Abdominal: 90cm
Hip: 106cm Hip: 106cm
Arm relaxed: 38.5cm Arm relaxed: 38.5cm
Arm Flexed: 43.5cm Arm Flexed: 43.5cm
Thigh: 57.5cm Thigh: 57cm



Skin fold (Calliper)  Skin fold (Calliper) 
Chest: 3.9mm Chest: 3.7mm
Abdominal: 22.6mm Abdominal: 12mm
Hip: 13.8mm Hip: 10.9mm
Triceps: 6.0mm Triceps: 5.9mm
Sub scapular: 12.3mm Sub scapular: 11.3mm
Thigh: 9.7mm Thigh: 9.6mm
Biceps: 4.2mm Biceps: 4.2mm


5 days later measurements… Back to normal eating 2x a day & training schedule.                

Body weight: 91.2kg.                                      

Chest: 113cm

Abdominal: 89cm

Hip: 105cm            

Arm relaxed: 39cm

Arm Flexed: 44cm

Thigh: 58cm


Skin fold (Calliper) 

Chest: 3.6mm

Abdominal: 12mm

Hip: 10mm

Triceps: 4.9mm

Sub scapular: 10.3mm

Thigh: 8.8mm

Biceps: 2.9mm


* The conclusion is that I’ve lost very minimum amount of muscle mass which was even better 5 days later, but the body fat% remain very low, so yes the benefits are sustained if you keep a real food nutrition lifestyle after the 72 hours fasting experience, I can’t wait to do it again simply because it felt incredibly great!


Would you like to join me next time?

Fat adapted individuals wouldn’t struggled so much with the absence of food simply because your body is really good in having access to your own fat stores. Literally your body is eating your own bacon 😉


Health Benefits of Intermittent Fasting

Fasting is historically commonplace as it has been a part of spiritual practice for millennia. But modern science has confirmed there are many good reasons for fasting, including the following:

Normalizing your insulin and leptin sensitivity, and boosting mitochondrial energy

efficiency: One of the primary mechanisms that makes intermittent fasting so beneficial 

for health is related to its impact on your insulin sensitivity.

While sugar is a source of energy for your body, it also promotes insulin resistance when 

consumed in the amounts found in our modern processed junk food diets. Insulin 

resistance, in turn, is a primary driver of chronic disease—from heart disease to cancer.

Intermittent fasting helps reset your body to use fat as its primary fuel, and mounting 

evidence confirms that when your body becomes adapted to burning FAT instead of sugar 

as its primary fuel, you dramatically reduce your risk of chronic disease 

Normalizing ghrelin levels, also known as “the hunger hormone”

Promoting human growth hormone (HGH) production: Research has shown fasting 

can raise HGH by as much as 1,300 percent in women, and 2,000 percent in men,2 which 

plays an important part in health, fitness, and slowing the aging process. HGH is also a fat-

burning hormone, which helps explain why fasting is so effective for weight loss

Lowering triglyceride levels and improving other biomarkers of disease

Reducing oxidative stress: Fasting decreases the accumulation of oxidative radicals in 

the cell, and thereby prevents oxidative damage to cellular proteins, lipids, and nucleic 

acids associated with aging and disease.

There’s also plenty of research showing that fasting has a beneficial impact on longevity in animals. There are a number of mechanisms contributing to this effect. Normalizing insulin sensitivity is a major one, but fasting also inhibits the mTOR pathway, which plays an important part in driving the aging process.

Intermittent fasting is by far the most effective way I know of to shed unwanted fat and eliminate your sugar cravings. Since most of us are carrying excess fat we just can’t seem to burn, this is a really important benefit. When sugar is not needed as a primary fuel, your body will also not crave it as much when your sugar stores run low.

As mentioned above, the other mechanisms that makes fasting so effective for weight loss is the fact that it provokes the secretion of HGH—a fat-burning hormone that has many well-recognized “anti-aging” health and fitness benefits.

Last but not least, intermittent fasting has also been identified as a potent ally for the prevention and perhaps even treatment of dementia. First, ketones are released as a byproduct of burning fat, and ketones (not glucose) are actually the preferred fuel for your brain.


Long Fasts: Other Benefits

In addition to weight loss, fasting also promotes autophagy, which is like a “spring cleaning” for your cells. Since your body is essentially eating itself, it has a chance to get rid of any junk or waste material that may have built up, and repair the damage of oxidative stress. This is one of the biggest benefits of fasting even for people who are already at a healthy weight, since it has powerful anti-aging and muscle-building properties.

One study also found that an extended fast (10 days on average) was beneficial to patients with hypertension, also noting that even though the patients didn’t embark on the fast to lose weight, all of them did – average weight loss was around 15 pounds. Longer term fasting (up to 5 days) may also have some benefits for chemotherapy patients.

Another benefit of extended fasting is purely mental: for many fasters, it’s a way to “re-set” their relationship with food, break free from patterns of emotional eating, or start fresh at the end of the fast. Fasting is part of many religious and spiritual practices because of its value for meditation and mindfulness. Bear in mind that this doesn’t happen automatically: it requires a high level of self-awareness and effort on the part of the faster. It’s a very useful tool, but it’s not a miracle cure.


  • People that would be best served to avoid fasting include those living with chronic stress (adrenal fatigue), and those with cortisol dysregulation. Pregnant or nursing mothers should also avoid fasting.

* Always consult a Dietitian before trying any strategy with intermittent fasting to make sure it makes sense with your plan/ goals/ lifestyle and health profile.


Marcelo Mesquita / Co Founder of Intense Health Clinics.




Marcelo is the co-founder and Director of Exercise Physiology at Intense Health, Perth's #1 Private Strength Training and Nutrition Clinics.

Marcelo is the co-founder and Director of Exercise Physiology at Intense Health, Perth's #1 Private Strength Training and Nutrition Clinics.