Nutrition is a big part of how we look and feel and there are many things you can do to improve it, but I don’t want to sacrifice things which I enjoy and fun – think occasional sweets, junk food, beers and wine. And before recently water fast is not something I considered.
However, fasting could be one of the solutions and in one way or another has been a hot topic over the last several years – intermittent fasting, 5-2, time restricted feeding, you name it. However, all of them have one thing in common; they are not fasting as such. You might reshuffle your calorie intake timing a bit, lower it on certain days but rarely go over 24 hours without consuming calories.
Recently a more extreme version of fasting, i.e. proper water fasts (or better to say zero calorie fasts) started to attract the attention of nutritionists and scientific community. They are not new and have been part of certain cultures and religions for millennia but never entered the mainstream until recently.
Given I had good experience with more mild forms of fasting and all the benefits claimed by longer, 3+ days fasting – I decided to jump on a deep end and try full 5-day water fast.
There are numerous scientific evidences that prolonged fasting causes numerous health benefits, in part through the process of autophagy – where in absence of nutrition the body start consuming its own cells. Sounds scary but quite the opposite – it starts with the weakest cells which once the fasting is done are replaced with new healthy ones. Therefore, your body naturally regenerates. In mice, four days of a diet that mimics fasting, decreased the size of multiple organs/systems; an effect followed upon re-feeding by an elevated number of progenitor and stem cells and regeneration
One recent study shows (see references), that prolonged fasting lasting at least 48–120 hours (2-5 days) promotes cell stress resistance, self-renewal and lineage-balanced regeneration.
Other recent studies have shed light on its role in adaptive cellular responses that reduce oxidative damage and inflammation, optimize energy metabolism and bolster cellular protection. Fasting helps reduce obesity, hypertension, asthma and rheumatoid arthritis. Thus, fasting has the potential to delay aging and help prevent and treat diseases.
Fasting is also an easy way to get into Ketosis (keto diet). It takes anywhere between 24 hours and 3 days for your body to enter ketosis when fasted.
Finally, another study demonstrated that a 48 hour fast decreased weight, heart rate, and systolic blood pressure while improved mental flexibility.
That’s the simplest part – you just stop consuming any calories for five days. Coffee, tea and calorie-free drinks are allowed, i.e. diet coke (although purists would say water only).
You would need to supplement with sodium to prevent muscle cramps – I have settled on two tablespoons of table salt a day, first thing in the morning.
Physical activity is not recommended but would say mainly due safety reasons as you do not want to take chances fainting in the middle of a workout.
Given it was my first extended fast, I decided to have a very light social schedule during this time, limiting it to work and home activities as did not want to be tempted by all the foods and drinks around me on one hand while being grumpy around people on the other.
Energy: 3/3 – Energy levels as normal, given I had a meal yesterday – so fairly typical day, not any different for any when you skip breakfast/lunch. By the end of the day I was getting extra hungry but no noticeable impact on my energy.
Mood: 2/3 – Fairly usual mood as well, until I got very hungry in the evening and a bit irritable. That said most of the day was fine.
Sleep: 3/3 – Nothing to report – the sleep was ok.
Appearance: No noticeable differences so would use as a baseline.
Conclusion: a Usual day other than some extra hunger and grumpiness in the evening.
Weight: 85.4kg / 9.6kg fat / 50.9kg water / 72.5kg muscle.
Energy: 2/3 – A bit less energy than usual but still enough to get on with daily activities. I would’ve expected it to dip, but on the other hand, I haven’t been exercising so was saving a bit there.
Mood: 1/3 – Woke up still hungry and grumpy. Was irritable all day and the only thing I could think about was food. I guess it the usual effect of when you cannot have something that’s the only thing you crave.
Sleep: 1/3 – Had a terrible sleep – tossing and turning all night, not being able to fall into proper deeps sleep. Woke up feeling pretty broken.
Appearance: Did not notice any difference vs Day 1.
Conclusion: Be mentally prepared that thoughts of food are going to occupy your mind and attack you every second you are not busy with something else – so ensure you keep yourself busy!
Weight: 84.9kg / 8.8kg fat / 51.2kg water / 72.7kg muscle.
Energy: 2/3 – Energy levels still at a good level – at least for my job in the office. Being in front of a screen and on the phone guess does not require much energy to start with, and I had plenty for that.
Mood: 2/3 – It feels that the worst bit is over and I can get on with my life. I no longer imagine doughnuts flying around every time I close my eyes and can properly focus on other things.
Sleep: 3/3 – Finally a good night of sleep. Either the body required some time to adapt or the fact that I was not as stressed today – in any case, it felt much better today.
Appearance: It looks like I started leaning out a bit around my waist but nothing dramatic so far.
Conclusion: Day 3 seems to be the tipping points – making the first two the hardest ones with things looking up from then on.
Weight: 83.8kg / 8.1kg fat / 50.9kg water / 72.2kg muscle.
Energy: 3/3 – Energy levels are much better than yesterday – in fact feeling quite energetic today. Not quite energetic to WOD but definitely could go on a gentle jog or a bike ride. Energy levels are very stable as well throughout the day, without being tired towards the end of the day as usually I am.
Mood: 3/3 – Mood was quite good as well – less irritable than in previous days. The focus is still good and easily can work through large volumes of work. Perhaps it is due to stable energy levels hence can start and finish a task in one sitting.
Sleep: 2/3 – Sleep wasn’t great as couldn’t fall asleep for a long time and when did – it didn’t feel like a deep sleep. Also, a fire alarm at 5 am did not help – however, did manage to catch a couple of hours of zzz’s after it.
Appearance: Subjectively significantly leaner compared to Day 3, with not much in-between skin and muscles. Also, could be the fact that I am more dehydrated than usual and did not exercise for several days hence less muscle retention in general.
Conclusion: It feels like a definite improvement vs previous days – if I am past the through and my body has finally adjusted to no food intake.
Weight: 81.6kg / 8.0kg fat / 50.8kg water / 71.7kg muscle.
Energy: 3/3 – Feeling great today – even physically I feel much stronger. Still not even close to pre-fast 100% but much better. Not sure whether it is due to better sleep of the body adjusting – I would guess mostly the latter.
Mood: 3/3 – General mood is great – better than previous days but in part due to also being excited to finally start eating and drinking.
Appearance: Probably the biggest change vs previous days – I had a real trough in-between sides of my abs, where I could fit ½ of my palm. My flatmate who hasn’t seen me for three days told me that I look more sculpted and one clothes size smaller overall. I would attribute it to less water retention around the body and low glycogen levels on general.
Sleep: 3/3 – Sleep was quite good, although it took me a while to fall asleep – I did not feel tired, to be honest, and that could be the reason. Not alert or worried but just not tired – perhaps next time I do the fast I should consider doing some moderate exercise to actually physically tire myself out.
Weight: 80.7kg / 7.8kg fat / 48.7kg water / 71.6kg muscle.
Energy: That’s an interesting one – my mental energy levels were amazingly stable from waking to going to sleep. I could sit and work all day – haven’t been that productive in ages. However, that’s applicable only to mental work – my physical energy levels were quite low so definitely didn’t feel like WODing at any point.
Mood: You get moody on the first couple of days – a combination of not being able to eat, headaches from low blood sugar and initial dip in energy levels. However, it gets better on the day three, so it makes sense to start the fast when you do not have many social obligations and can power through them.
Sleep: Had problems with sleep at first, but to be honest have a sub-part sleep in general. Would add some light cardio or yoga next time around to tire me physically on the one hand and prevent excessive muscle loss on the other. However, would limit it to perhaps spinning as the safest of the whole lot and the lest to cause accidents.
Appearance: Given the absence of exercise I would think that I lost some of the muscle tone hence over the five days the changes are hard to spot at first – as diminishing definition is replaced by lower fat / water percentage. However, when compared side by side in person, and looking at clothes fit – I definitely look one clothes size smaller. However, would expect most of it to go back once I restart eating and exercising.
Weight: Nearly a 5kg drop – but I wouldn’t get too excited. First of all, reading above were done using a smart domestic scale (Nokia Scale +) so not terribly precise and consistent – but could give you a direction. 11k calorie deficit (2.3k per day as per Dexa scan) equates to a 1.5kg fat loss, but it is not all that simple. I would estimate that out of the 4.6kg drop, 3kg would be water/glycogen, 1kg fat and the rest muscles.
I would definitely repeat the fast, or even make it my routine and do it once every 3-5 months. Even if there are no positive long-term effects of the fast, it feels good to give your body a rest and work on the self-discipline – while freeing up time and focus for important mental tasks.
Secondly, it made little sense to break the fast in the evening and even more so to have a heavy meal associated with dinner – so might as well go on for a 5.5 day fast i.e. evening of Day 0 to morning of Day 6 and start off with a light breakfast, building eating back over the course of the day.
Thirdly, I started to feel fasting going into gear around Day 3, leaving only two days of actual fasting – next time I would extend the fast even longer, say 6.5 days till the morning of Day 7.
Finally, on some nights I couldn’t fall asleep as didn’t feel tired. While proper training is definitely out of the question, I would re-introduce some mild exercise – perhaps yoga or low intensity / steady state spinning.
Body composition scales – to measure weight and body parameters (the one I am using).