Fasting, but not as you know it

Embarking on a Five Day Fasting Mimicking Diet with ProLon®

Fasting has historically been very tough for me. I’ve tried it before without success, especially as it always felt much more like a diet of deprivation (and unmanageable hunger!) rather than a metabolic reset that could bring a myriad of health benefits.
My previous experience of DIY fasting was one of headaches, feeling terrible and giving up. Fasting, I thought, was just not for me.
However, my ears soon pricked up when I heard Professor Valter Longo presenting the results of his fasting mimicking diet.

[NB This blog post is not a paid advertisement for ProLon® – I fasted and wrote about my eperience completely independently]

Professor Longo was speaking on a panel I was chairing at the European Congress for Integrative Medicine in November 2021. We got talking in the break and I found his passion for what he does compelling.

His evolution of twenty years of research into fasting and longevity was utterly fascinating, and his specially designed five-day fast for people who can’t normally fast was something that I wanted to explore, both in a professional and a personal capacity.

My Story

I felt I was in trouble since entering the menopause late in life. I’d noticed that in recent blood tests my bad cholesterol (low density lipoproteins – LDL) was climbing as was my blood pressure, and that my abdominal girth was increasing.

My genetics have a strong thread of Metabolic Syndrome on one side of the family, and I could see where things were going. Metabolic Syndrome is increasingly common and combines a degree of insulin resistance with weight gain, hypertension, and fatigue. As the body initiates a homeostatic (rebalancing) response – and switches off from rising insulin levels in the blood – the cells get starved of glucose.

According to Dr Pradip Jamnadas in a recent interview about fasting and the incredible changes he had seen with his patients, the body is designed to be a hybrid engine – i.e. running on glucose when food is abundant and running on ketones at times of scarcity. (That podcast is well worth a listen – find it on ‘Feel Better Live More’ with Dr Rangan Chatterjee – link below.)

Being able to move from one to the other is now called ‘metabolic flexibility’ and this is something I knew I didn’t have. If I get hungry, I get ‘hangry’ with my brain cells starving and unable to make that switch to burning ketones, the alternative fuel for the body.

So, to address my metabolic ‘in-flexibility’, I decided it was time for me try a different kind of fast – in particular, the five-day one designed by Professor Longo. A clinically tested and nutrient-based fasting ‘kit’ using his research has been developed and retails as a product called ProLon® (https://prolon.co.uk).

Making A Decision & Going For It

I chose ProLon® because of Professor Longo’s science and research behind it. That plus the idea of mimicking a fast but consuming just enough calories, mineral and vitamins to fool the body nothing bad is happening and that you’re not starving!

The first thing to say is it’s pretty expensive – £200 for five days. As it happens, my son found a discount voucher on the internet and I managed to sign up for a slightly cheaper £160. I know that’s still out of reach for lots of people and it’s something to think through for funders if fasting therapy was ever to become more widely accessible or even mainstream.

Secondly, you need to find a five-day window in your diary during which you can stick to the regime. It’s not as easy as it sounds and needs planning. You could lose a few friends if you turn up for supper at their house with your own sachet of minestrone soup!

Thirdly, you need a bit of resolve to just get on with it. I was very nervous as I was about to embark on the fast with visions of failing. In the end I started a week earlier than originally planned to end the waiting game. I now could NOT fail and waste that money.

The Fast – Day By Day

So, the ProLon® box arrived – white and bright and containing smaller boxes with all the food you needed for Days 1 to 5 pre-packed and measured out. It also came with a free branded litre bottle for the Prolon liquid on Days 2-5. (Side note: that water bottle occasionally leaked over my bag – you need to make sure the lid is screwed on tight!).

Although the planetary impact of waste was not great (snacks such as seven olives wrapped in small foil lined bags), psychologically I was helped by seeing the sachets of food to take me through the coming days. It was good to have everything you needed in those boxes. It was clear that this, and only this, was what I had to eat in the coming days.

Each daily box contained cup-a-soups, snack bars (nut based or choco crisp), olives, kale crackers, herbal teas, a dilute to add to water and supplements.

Day 1 started well and was in fact pretty easy. I knew that as the days went on it might become harder, but Day 1 was straight forward. I chose a Sunday start to see how I got on before work on the Monday. The two allocated nut bars which were nutritious and satisfying and I was active on the allotment. I didn’t get headaches or feel weak – it felt like a good start.

Day 2 started to focus my mind on the fast. I consumed a nut bar, cup of soup and kale crackers and then a minestrone soup cooked on the hob to give an air of something substantial with a yummy chocolate crispy thing to finish with – all low carb and vegan. On Day 2 I also started to consume the Glycerol containing drink to reduce protein loss with a hibiscus tea bag. A whole litre of that was programmed but I struggled with it as the day went on. It also tasted a bit like chemicals despite the addition of hibiscus (incidentally, hibiscus has become a new favourite herb tea!).

The night of Day 2 was unsettled, and I was hungry; waking into Day 3 was hard.

Day 3 – I rang my daughter who runs marathons for advice; I was ready to give up. She didn’t have much advice but gave me two such great pieces of news about her health and a close friend winning his right to remain in the UK. And with that I was able to carry on the day.  Line up friends or family to perk you up a bit if you need it!

Day 4 – I could feel the shift overnight as I slept really well and could feel a slow burn in my body. My day was dreamy with unlimited energy- something I never experience. I would say I always struggle with energy; intracellularly I feel my cells just don’t work very well. This day was different. I cycled, swam, walked with friends to watch a murmuration of starlings in Somerset – I was living off pure air. Please let this feeling go on for ever, I thought!

Day 5 – It didn’t…on Day 5 I was left tired and hungry, but it was Day 5 so I could see the end in sight. I had previously told myself that it was impossible to lose weight in the menopause but as the days went by and I calorie restricted to around 700 calories a day I was consistently losing around a third of a kg a day. By Day 5 I had lost 1.5 kg and I was very pleased.

A Few Things That Helped

I could have a cup of coffee in the morning. I felt I could do anything if I had that coffee. Yes, I can hear you saying that one will have to give that up sometime soon – in next lifetime perhaps?!

The other thing for me was being distracted at work and having a structure which meant I didn’t need to think about food – the thinking was done for me. I’m a foodie, so I did add fresh herbs to my minestrone mix and admit that on one day I added a bit of fresh spinach in desperation (see below for confessional paragraph!). I was a little afraid of constipation but in fact that was not a problem.

Something to be aware of is ghrelin – the hormone that reminds you to eat (in case you might have forgotten!) As the three waves of ghrelin were released at around breakfast, lunch and dinner time I became very hungry. Breakfast was manageable with coffee and nut bar, lunch was OK as I don’t eat much then anyway…but the 5.30pm ghrelin wave was fierce – especially so on Day 2.

In fact in my head I heard my inner child shouting, “she’s trying to starve us – she’s going to kill us!”.  I really had to settle her down and let her know that it was all going to be OK. The ghrelin wave falls after about 45 minutes and that is definitely worth knowing. Remember, hunger is your friend – when you feel hungry, you’re fat burning.  Being able to eat something regularly at mealtimes, even if very small, was very helpful for me.

A Spiritual Experience

The other thing is the spiritual element of my fast. I meditated from Day 1 and had a powerful experience of the grief of the loss of my brother when he was 26 and I was 23.

I subsequently had a dream of him, and we held hands. It felt like my grief was unlocking and in an acupuncture treatment on Day 2 I wept uncharacteristically about not being able to let go of him. I imagined laying him in a longboat and setting fire to it. I cast him into the flow of the water and was allowed to swim alongside him.

On Day 4 I had an experience of spaciousness in my meditation; in fact for the first time I experienced mind, body and spirit as tangible things. I know that professionally I espouse a mind-body-spirit approach to health and wellbeing and for that very reason had set up a Centre for Integrative Medicine, but this was me getting a personal experience of all three dimensions within my human existence. It was almost as if in laying less emphasis on the physical body I could feel my spiritual body. Crazy, I hear you say – was she hallucinating through lack of food? Maybe you’re right, maybe not…

Time To Confess

Having shared my spiritual experience, next is the confessional. Some days I just couldn’t hack it and would have a single oatcake. This would really settle the hunger down. I wonder if ProLon would be willing to give us a list of the healthiest cheats available?  I imagine they don’t want to give us any ideas though!

In addition, because I was worried about constipation, I did occasionally have seven blueberries and five raspberries (they tasted so good!).

The other confession is that on Day 3 when I was thinking I couldn’t do it, I ate the chocolate crispy thing from Day 4. Never has anything tasted so good. This meant of course that on Day 4 I didn’t have the chocolate crispy thing, but Day 4 was my enlightened day when I didn’t need to eat at all. Swapping food form different days is forbidden – do what they say, not what I do.

The Results…

Since finishing the five-day fast I have more energy overall without a doubt. I am also more accustomed to hunger – and that’s not a bad thing at all. I’ve been able to embark on a fast day in this following week and so far, have not regained any weight lost.

My blood pressure is significantly better, and I am already planning with enthusiasm my next ProLon five-day fast in about two to three months. I haven’t yet checked my lipids, but my abdominal girth is down to 32 inches…there’s still a way to go.

I’ve decided to follow the 5:2 fast between five-day fasts to see how I get on. I have to admit that for my two intermittent fasting days I’ve already planned a simple and much cheaper menu. I’ll be eating a nut bar, a cuppa soup, a bowl of homemade vegetable soup and a Paleo chocolate bar for pudding.

For those of you wanting to try something even more adventurous and perhaps more impactful, Dr Pradip Jamnadas recommends water only fasting. It’s not for the faint hearted and should really be done under the supervision of a health professional. I have to admit that a water only fast would leave a big void for me mentally (and physically!) but maybe it’s something for the future if I can keep the meditation going…



Read – Professor Valter Longo’s research in his brilliant and really accessible book, the Longevity Diet (https://www.valterlongo.com/the-longevity-diet/)

Listen – Dr Pradip Jamnadas’ podcast conversation on fasting for heatlh and his suggestion of a water fast https://drchatterjee.com/why-this-cardiologist-recommends-fasting-with-dr-pradip-jamnadas/

Fast – Try out the ProLon® Five Day Fasting Mimicking Diet – https://prolon.co.uk