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ProLon – the Easy, Evidence-Based Way to do a 5-Day Fast

ProLon - the Easy, Evidence-Based Way to do a 5-Day Fast

Designed to take the headache out of fasting (not literally, you may still have a headache for the first day or two), ProLon was invented by Valter Longo, an esteemed longevity researcher who has a long string of accolades and credentials. In fact, Dr. Longo’s latest book is aptly titled The Longevity Diet. 

His work on intermittent fasting and fasting mimicking diets (FMD) has focused largely on using fasting as a way to enhance cancer treatment and mitigate the negative impact of chemotherapy, with considerable success. Now, however, many people are using ProLon to help lower cholesterol, triglycerides, and blood sugar, combat insulin resistance, promote weight loss, and enhance immune function.

What is ProLon, and is their “fasting mimicking diet” product rooted in science?

Before we dig into the research on ProLon, fasting, and calorie restriction, let’s quickly define some key terms:

Fasting – a complete absence of food intake. Prolonged fasting usually means at least 3 days in humans.

Intermittent fasting or alternate-day fasting – a long-term practice of fasting every other day, with standard food intake on non-fasting days.

Fasting mimetics – pharmacological agents that trigger some of the effects of fasting.

Fasting mimicking diet (FMD) – a dietary regimen composed of macronutrients and micronutrients, with minimal calorie restriction, designed to trigger a response akin to fasting. Specifically, to influence levels of glucose and IGF-1.

Caloric restriction – A 20-40 percent reduction in standard calorie intake, but a standard intake of micronutrients (i.e. vitamins and minerals, etc.).

ProLon is a fasting mimicking diet (FMD), which typically refers to a diet that contains no animal protein, low amounts of plant protein, very low amounts of saturated fat, high amounts of unsaturated fats, very low amounts of sugars, and high amounts of complex carbohydrates. This is in stark contrast to a typical Western style diet where animal protein, saturated fats, and sugars tend to be present in excessive amounts and intake of complex carbohydrates and unsaturated fats tends to be low.

Now that’s out of the way…

What is ProLon?

The ProLon program includes nut bars, chocolate bars, kale crackers, tomato soup, olives, herbal teas, and various vitamin pills to get you through the five days. On Day One, the food provides 1150 calories, dropping to 800 on Day Two and a little lower beyond that.

The ProLon diet provides enough protein, carbohydrate, and fats, as well as micronutrients, to keep you alive over the 5-day period and appears to offer many of the benefits of fasting without actually fasting. These benefits likely include weight loss, reductions in cholesterol and blood glucose, less insulin resistance, stem cell regeneration, and a slowing down of the ageing process.

Why was ProLon invented?

Valter Longo designed ProLon to support people undergoing chemotherapy or radiotherapy for cancer. This is, in part, because intermittent fasting has been found to reduce levels of insulin-like growth factor-1 (IGF-1). Lowering levels of IGF-1 can enhance the resistance of normal cells to chemotherapy-dependent damage while simultaneously increasing the susceptibility of a large number of tumors to chemo and radiotherapy. 1 2

IGF-1 is an important molecule needed to promote tissue growth in the body. We need it for muscle growth, for instance. Unfortunately, too much IGF-1 is linked to abnormal, excessive growth, i.e. cancer. 

Excessive levels of IGF-1 are also implicated in metabolic issues that predispose a person to type 2 diabetes. Interestingly, though, low levels of IGF-1 have also been linked to an increased risk of type 2 diabetes. 3 Genetics may have a role to play here, given that our genes can influence growth hormone receptor activity, meaning that IGF-1 could have a bigger impact on some individuals compared to others.

ProLon may have been designed to support people during cancer treatment, but it is now being used and researched for its potential anti-aging benefits. That’s because Longo, and many others, are convinced that decreasing IGF-1 levels can have a significant effect on slowing down the aging process by promoting stem cell-based regeneration and immune system ‘rejuvenation’.

Is there evidence for these claims? In short, yes, the science is solid on this front, but we could definitely do with more research to round out the picture.

Fasting research – a quick overview

Several non-human animal studies have shown that fasting is associated with dramatic increases in lifespan and ‘healthspan’, i.e. the number of years of healthy life the animals can ‘enjoy’ (in the laboratory). As for humans, the research on fasting (as defined as a total lack of food intake) is largely speculative. Not surprisingly, it is hard for researchers to get ethics approval and funding for full-on fasting studies, meaning there is scant literature available for us to assess.

Indeed, there is no long-term research on fasting in humans. This means that we simply don’t yet know if the short-term beneficial effects on cholesterol levels and blood glucose actually translate to a reduced risk of cardiovascular disease or diabetes.

There is a growing body of research on fasting mimicking diets and ProLon, though. And the evidence clearly supports claims of numerous benefits from this 5-day plan when it is used once a month for three consecutive months. Specifically, ProLon has been seen in clinical studies to reduce abdominal fat, maintain healthy blood glucose levels, and promote lower levels of C-reactive protein and IGF-1.

Calorie restriction and fasting – What the research says

You can’t understand ProLon and the fasting mimicking diet without understanding its calorie restriction roots. Calorie restriction research was the catalyst for Longo’s fasting research. His mentor, Ray Wolford, was one of the participants of the Biosphere experiment, in which a group of researchers lived for two years on a calorie restricted diet in an enclosed terrarium designed to mimic Mars. Although calorie restriction had shown promise in extending lifespan in animal models, the Biosphere was a failure. People simply don’t want to live the austere life a calorie restricted diet requires, and Longo cites the gaunt appearance of the Biosphere participants as they emerged from the experiment as his light bulb moment in which he realized we needed a better way. 

Biosphere taught us that chronic calorie restriction can be a real challenge for many people and may not be advisable, especially for older adults whose ability to absorb micronutrients is often impaired. ProLon or another FMD certainly offer advantages in this regard, especially given the likelihood that an FMD can combat age-related immunosenscence (which we will get to in a moment). 

In a study carried out by Longo and colleagues, an intermittent fasting protocol (a four-day FMD twice a month) increased lifespan in mice by around 11 percent on average. The FMD also led to reductions in visceral fat, cancer incidence, skin lesions, and bone mineral density loss, while enhancing the immune system. 4 The FMD was even associated with improved cognitive performance in older mice, likely due to enhanced neurogenesis in the hippocampus, as well as reduced IGF-1 activity, modulated protein kinase (PKA) activity, and elevated NeuroD1. The latter two are factors in neuron differentiation and protection.

Extending this research to humans as part of a pilot clinical trial (detailed in the paper as above), Longo and co-authors noted that:

“three FMD cycles decreased risk factors/biomarkers for aging, diabetes, cardiovascular disease, and cancer without major adverse effects, providing support for the use of FMDs to promote healthspan.”

Some of the beneficial changes included lower levels of C-reactive protein, and reduced body weight and body fat, without loss of lean mass.

In other studies, mice who fasted for two days and humans who fasted for five days had decreases of over 30 percent in blood glucose, over 50 percent in IGF-1, and a 5-10-fold increase in the protein that binds to IGF-1 to decrease its activity. 5

Basically, all of the benefits listed above as associated with calorie restriction are also associated with an FMD, and an FMD is, arguably, much easier to incorporate into your regular lifestyle. FMDs like ProLon may also have additional benefits for addressing immunosenescence and autoimmune issues.

Prolonged fasting and immune system function

As we age, the ability of our hematopoietic stem cells to form new immune system cells declines, leading to immunosenescence (basically a slowing down of the immune system). This is why older adults are more vulnerable to infections. Our immune system cells are also more likely to become dysfunctional as we age. This can lead to the development and progression of autoimmune disease, where the immune system falsely identifies and targets the body’s own cells as foreign invaders. Diseases such as Multiple Sclerosis, Rheumatoid arthritis, and others are a result of immune system dysfunction, with treatments often focusing on blanket immunosuppression that also leaves sufferers at increased risk of infection. Prolonged fasting has been proposed as a way to not only reverse immunosenescence, but to also address the dysfunction at the heart of autoimmune disease. Prolonged fasting appears to ‘reset’ the immune system by killing off the cells that erroneously target the body’s own cells, while stimulating the regeneration of the stem cells needed to create functional immune system cells. 6 Fasting downregulates an IGF-1/PKA pathway in stem cells, it protects hematopoietic cells from chemotoxicity, and promotes the self-renewal of hematopoietic stem cells to reverse immunosuppression. This has been well documented in the scientific literature and is an exciting development in autoimmune research and longevity. In one study, prolonged fasting caused a 28 percent decrease in white blood cell number, which was fully reversed after animals resumed eating. 7 This means that almost a third of the white blood cells were renewed after the fast, helping to refresh the immune system, with potential benefits for those with aberrant immune system cells. For the average person without an autoimmune disease, fasting can also help stimulate stem cell regeneration which may help prevent or delay immunosenescence and autoimmune issues.

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Should you try ProLon?

After looking at the research, I’m convinced that ProLon has some major selling points. Aside from its likely benefits for anyone undergoing cancer treatment, there may well be some considerable benefits for healthier individuals as well as those with immune system problems.

ProLon makes it super simple to give fasting a try without having to worry about malnutrition. The product packaging is easy on the eye and the food, by most accounts, tastes pretty delicious! The cost is likely to be prohibitive for many people, however, although there are discounts available if you buy in bulk or sign up for a subscription.

One interesting additional benefit of ProLon is that it seems to make a person reassess their relationship to food (and alcohol!). After ‘fasting’ for five days, you’ll probably think harder about everything you put in your mouth. Smaller portion sizes may suddenly seem much more reasonable, and you’re likely to be better at forgoing snacks and foods that were unhealthy habits. That said, there are probably easier ways to promote mindfulness around food.

Interested in a mimicking fasting diet but don’t want to try ProLon? Your best bet is to work with a qualified nutritionist. That’s because trying to design your own is liable to lead to dangerously low blood pressure, blood glucose, palpitations, and other possibly fatal complications. This isn’t just marketing hype. Even on ProLon, which took decades to design, your assigned nutritional advisor will likely tell you to avoid driving or any strenuous or stressful activity because it could be more dangerous than usual.

In fact, the makers of ProLon have a long list on their website of folks who shouldn’t use the product. If none of these caveats apply to you, it seems well worth giving ProLon a go. If you do, be sure to swing by the comment section to let me know how you get on.

Leigh Matthews, BA Hons, H.Dip. NT

Leigh Matthews, BA Hons, H.Dip. NT, is a health and wellness writer for Gene Food specializing in plant-based nutrition. Read her full bio here.

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