I have been experimenting with fasting for a while but I became interested in this diet last year, after listening to a podcast where Dr Longo, the brain behind the product ProLon,  was explaining the benefits of this way of fasting which include fat loss while maintaining muscle mass, antiaging effect,  natural ‘spring cleaning’ of the cells which means a lower level risk factor for many illnesses, stronger mental focus, better blood sugar regulation.  Who could argue with that? I have also been feeling quite sluggish lately so I can do with an overall boost, especially before my holiday in the sunshine!

You don’t need a pre-packaged meal solution to do this diet, but it does make it easier because, in this way, the ratios and percentages of nutrients have already been worked out for you. Getting this balance wrong, could result in the whole fast being ineffective and, according to Dr Longo, potentially dangerous.

ProLon is a nutrient dense, backed by science modified type of fasting. Basically, you don’t completely abstain from food, like in a real fast, but you consume a small amount of food -consisting of plant-based soups, bars, snacks, teas and supplements- which is designed to maximize the beneficial effects of fasting while providing nourishment and minimizing hunger.

Before you scream in excitement -did I just say there is food during a fast?-  let me tell you that this is not the average food you eat daily , it’s more like the food astronauts survive on -or so I think anyway- but if you struggle to do extended fasts, like I do, then eating a little might be easier than not eating at all.

DAY 1 (my food is in the picture above, a total of 1,100 Kcals)

As far as the first day went, all I can say is that it wasn’t plain sailing. I felt quite light headed and tired during most of the day but I wasn’t as hungry as I thought I’d be.

I ate a lovely nut-based bar for breakfast and drank huge amounts of the herbal teas provided during the whole day. The main meals are vegetable-based soups and today the tomato soup tasted ok. There were also some nice herbs crackers and olives to go with it.

 I always have dinner quite early so the evening was dragging on a bit and I decided to have an early night not to focus on my empty stomach.

DAY 2 (800 kcals)

I woke up hungry and I struggled with hunger for the whole day. 

There was less food available for today, but they add in a lovely solution to dilute in water and sip through the day which tasted nice.

I had a busy day running around with my daughter and the thing that strikes me the most about today is that I have been very grumpy. Irritability is a possible side effect of low calorie and low protein diets as well as anxiety, depression, dizziness, fatigue, drowsiness, muscle aches, nausea, headaches and spinal pains. On their list of potential side effects, they also mention constipation, fainting, low blood pressure and low blood sugar. In a nutshell it’s safe to say that this is not for a walk in the park.

My blood sugar levels were quite stable during the day and my keto strips told me that I have entered ketosis. You might have heard about the ketogenic diet and getting into ketosis which is a normal metabolic process which the body does to keep working. When you follow a very low calories or low carbohydrates diet and the body doesn’t have enough glucose to burn for energy, it starts to burn fat instead. Fasting is another way of entering ketosis quickly but it all depends on the individual. My normal diet is low in sugar and carbs -the only carbs I eat regularly are fruits and vegetables- so I am not surprised to be in a state of ketosis already.

Cooking dinner for the rest of the family was a challenge and the lovely tiny, little chocolate bar (picture below) at the end of dinner was the highlight of the day!

I also struggled to fall asleep and felt very cold during the whole evening. Feeling quite cold is unfortunately common during fasting, and the cold weather doesn’t obviously help so I went to bed with a fleece and socks. Good job my husband is away this weekend!

DAY 3 (800 kcals)

I woke up with lots of energy and not feeling hungry at all. Such an improvement from yesterday.

I haven’t felt lightheaded either, but I had a dull back ache which is rather annoying as I needed to spend some time sitting down today catching up with my writing.

It’s interesting to notice how I haven’t been hungry, but I would have liked to eat something extra despite my soups and crackers.  Fasting is very much a mind game, the body adjusts to the lack, or very little food, and hunger pangs tend to fade. It’s the mind which is harder to distract!

My evening meal is just a vegetable soup, no cracker or olives to go with it but I don’t mind. My husband and daughter’s very rich dinner doesn’t bother me at all either.

I am feeling very awake and super energised. I am writing this late in the evening (it’s almost 11 o’clock at night which is late for me) and I am planning on starting my packing as soon as I finish this because I don’t feel sleepy at all. This is very unusual for me because I am usually in bed by now, if not earlier. 

Two more days to go, I feel like I can definitely do this!

DAY 4 (800 Kcal)

I woke up very early today despite going to bed late and I felt ok all morning.

At breakfast I was a little bit hungry and craved a coffee which I didn’t have. The plan doesn’t include coffee but apparently if you are really struggling you can have one without anything in it. I like my coffee with milk, so I decided to forget about it and have some peppermint tea instead.

I felt ok during the afternoon, the backache is gone and the grumpiness too which is good news but today I felt hungrier than yesterday. Cooking dinner was a real struggle and it was hard not to taste the Bolognese sauce I made for the rest of the family. Cooking while fasting -or semi-fasting- is not my idea of fun. Luckily, I am busy packing tonight – and writing this! – so I am not thinking about food. This is the thing, it’s more to do with the mind again because my stomach is not complaining. I can’t  honestly say that I am hungry right now; I just would like to eat something.

This experiment made me realise that I don’t always eat because I am hungry…. I guess I am human too! We are all emotional eaters at some level, and this is ok because food is not just nutrients. However, if you have difficulties losing weight or maintaining your ideal weight then this needs to be addressed. Even eating healthy food when you don’t really need it can lead to weight gain, tuning in to your hunger clues is important and I guess that fasting greatly helps with this.

The other thing I have noticed is that I have a lot of energy, and I am quite focused too. Usually when people go on very low calories diets, they complain of fatigue and drowsiness but, after a rough Day2, I have been feeling great.

One more day to go!

DAY 5 (800 Kcal)

Finally, the last day of the fast mimicking diet. I say finally because I am bored of the pre-packed soups, except for the tomato soup in the picture above which was my favourite. I am missing fresh vegetables and protein. It turns out that this diet is 45% carbohydrates (all coming from vegetables and a little quinoa), 45% is fat (mainly olives, nuts, and some omega 3 supplements) and only 10% is protein (coming from nuts and vegetables).

My normal diet is much higher in protein than this, and so it doesn’t surprise me that today I have been craving not only fresh foods, but also nuts/seeds/meat and eggs. Dr Longo argues that the special ratio of these nutrients is vital for feeding the microbiome -the bugs that live inside us and especially in our gut- which plays a huge role in our health particularly in the function of the immune system.

Today I haven’t felt particularly hungry -hunger hasn’t been an issue beyond day2- I was just craving and missing real food. Energy bars and pre-packed soups are not ideal if you are used to cooking everything from scratch. I felt great with lots of energy and mental focus again. The only side effects I can report are constipation and a few little red spots on my face which I am sure will go once I start eating normal again.

Have I lost weight? I have lost 1.5 kg and the fat percentage on my scale went down a little which is  good news. Bear in mind that this diet is not aimed at weight loss even if some weight loss is to be expected.

Would I do it again? Dr Longo recommends doing a cycle -the whole 5 days of ProLon- regularly to get the full benefits. If you don’t have specific health issues you could do this twice a year, but if you suffer from an autoimmune condition for instance, you would benefit from doing this more regularly. As for me, I am thinking of repeating the cycle again in 6 months’ time, and this time I would also add some blood tests before and after to check what really happens on a cellular level.

A Day 6 ‘transition diet’, which is not included in the pack, is recommended before you go back to your normal way of eating. The meals suggested are liquids first (soups or juice) followed by some light meals of rice with small amounts of fish/meat/legumes. After any fasting it’s always good practice to ease back into foods slowly so not to give the digestive system a shock and avoid bloating and discomfort.

I am glad I embarked on this journey because I have learnt a lot about my eating habits and, although I can do 5 days of ‘astronauts foods’ in the name of longevity, I also know that pre-packed soups and meal bars are not really up my street! 

A word of caution, this type of diet is not suitable for everyone. Pregnant women, people who are underweight, anyone over the age of 70, people with liver or kidney disease, anyone on medication or suffering from low blood pressure or other pathologies (cancer, diabetes, cardiovascular disease and so on) must not go on this diet. If you are thinking of embarking on a fast or any type of diet, please consult your doctor or a health care professional first.