Here we are, eight months into 2020. Summer is almost over, and our world is still a little upside down.

During this time of isolation folks have been looking for inspiration. You may be finding that your normal eating habits are out of whack. Some may be eating less, some may be eating more. In either case, nutrition and well-being could be suffering.

A 5-Day Fast? Are you Joking?

Back in March, a colleague asked me if I’d like to try a fasting-for-longevity program, a “5-Day Fasting Mimicking Diet” called ProLon®. When I finally got around to doing it in May, a friend of mine commented: “I’m shocked that you are trying a fast!” She made this comment, because I have never recommended “dieting” of any kind, and a “fast” seemed extreme.

At a glance, this may seem like a gimmick. However, this is not a detox, nor crash dieting. The research about intermittent fasting is of interest to the scientific community. The initial story about this program made claims it could reduce belly fat and turn back the clock on aging. The science on mice and rats seems to show that various sorts of short-term fasting allows them to live longer, be slimmer, and have less disease. As a middle-aged, post-menopausal woman, the premise of this program led me to agree to try it out.

Longevity, Not Weight Loss

ProLon is a fasting-mimicking program that’s designed to offer the benefits of fasting without the hunger. The founder, Valter Longo, has spent years researching the physiology of aging. He feels that the occasional fast may help “boost health”.

The program markets itself as a way to “reset and rejuvenate”. Prolon® is not a weight loss program, but certainly some are drawn to it for that reason. Its primary claims however are to improve metabolic health, trigger autophagy (the clean up of damaged cells) and promote fat loss. Since fasting has sometimes been shown to put hunger hormones back in order, it could help support long-term weight loss.

According to the company, the Prolon® Fasting Mimicking Diet® is a scientifically designed 5-day “fast” that ranges in calories from 800 to 1100 per day. It works by “mimicking” a complete water fast, while actually still providing micro- and macro-nutrients to the body.

The easy thing about it is that the calories and nutrients for each of the 5 days are provided in convenient packaging. That takes all of the thought out of planning a mimicked fast. The program calculates sufficient vitamins and minerals, fiber and appetite sustaining healthy fats.

Salmon on a Charcuterie board with decorative vegetables

Fad Free

I have always focused on eating foods you enjoy and making sensible choices for both weight loss and health. I have never supported fad diets, or “dieting” for that matter. However, as you age, or go through various aspects of the lifecycle (teenage growth spurts, pregnancy, middle age, menopause), your metabolism does shift.

Even with the growing “health at every size” movement, in my clinical opinion, you still need to check in with your metabolic health. You can do so by getting an annual physical exam where you doctor will order blood work that can show any disease or metabolic syndrome.

There's no one thing you can abolish from your diet that's going to provide a fountain of youth, but finding a diet and lifestyle that works for you is important. Share on X

It may surprise you that I happen to be someone who needs external motivation to stay on track with a healthy habits. I’m also someone who has never had an issue with weight management until peri-menopause. However, I really should lose some weight now to keep my disease risks at bay. At only 5 foot 3 inches, restricting calories has always been a challenge for me since I don’t consume that much. I also have always had an active lifestyle. My blood pressure is well controlled (good thing I wrote a few books right?) with a small dose of anti-hypertensive medicine and a healthy low sodium DASH diet. However, losing 10 pounds would be healthy for my blood pressure and overall disease risk.

My Experience with the Prolon Fasting Mimicking Diet®

The program provides a box of all of the food, tea, and supplements you’ll consume each day over the 5 days (High fat, high fiber bars, herbal tea, water, olives, high fiber crackers and soups, a multi-vitamin and a fish oil supplement on some days). It is very little food. Caffeine is discouraged, but I did enjoy one cup of black coffee every morning (I wanted to avoid a caffeine withdrawal headache). Hydration is required, with either plain water or herbal tea throughout the day.

My goal in trying this program was three-fold:

  1. I wanted to see for myself, what this fasting-mimicking would feel like, and result in.
  2. I wanted to learn more about the science behind fasting, so that I could share it with readers.
  3. On a personal note, my hope is that it would help me achieve my post-menopausal weight loss goal going forward, by regulating my appetite hormones. If a 5-day fast could reduces your appetite, you’ll have an easier time eating to optimize weight going forward.

I began the program on a Monday. Of course, most people are going to feel hungry, especially the first two days. Day one was fine. I was surprised that I made it through the whole 5 days. On Tuesday (Day 2) I thought: “I’m never going to make it until Friday”. But I did.

My Surprising Findings

  • I found that by Wednesday morning, I was much more mindful about my appetite, thirst, hunger, and eating over the course of the week. Having only 10 or so small olives portioned out to enjoy as a snack really makes you savor each one.
  • I was also surprised how my hunger had suppressed by Day 3. It became easy to just hydrate and eat the small meals and snacks.
  • I occasionally experience reflux (another gift of aging and my genetics) and since I had no caffeine or alcohol over the 5 day fast, and didn’t eat after 6pm or so, I had no digestive issues.
  • I slept very soundly every night!
  • The food was good. While the soups are “instant” and they are made in Italy. They were quite good and include inulin fiber. I also enjoyed the Fast Bars and (believe it or not) the kale crackers.
  • I lost about two pounds by the end of the 5-day fast. It did, however, seem to “re-set” my appetite and reduce my desire for sweets, which resulted in an additional 3 pounds lost over the following three months.

As I mentioned, weight loss isn’t the primary goal here – it’s cellular health. I’ll cover more about the science behind fasting in a future science-heavy post.

Check in with a Dietitian

If you are considering this program or another type of intermittent fast, make an appointment with a dietitian near you. There is a lot to learn about your own eating habits. Multiple factors, including your diet, weight and medical history influence what’s right for you. For my personal health circumstances, I will likely adopt an intermittent fasting routine three or four times a year.

This program is not claiming to be a magic bullet. However, if you are finding yourself stuck, sluggish and unable to lose weight, you may want to check out Longo’s book and give it a try.