Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to weight loss and fasting.

ProLon is a fasting meal service, which sounds like an oxymoron. The brand describes their service as “precision nutrition for health and longevity,” and claims that their offering “is based on over 20 years of scientific research and over $36 million in R&D.”

But is ProLon actually proven in clinical studies to cause weight loss? How much weight loss is possible? How does ProLon compare to other popular weight loss programs like Jenny Craig? And how do real users describe the effects of ProLon?

In this article we'll answer all of these questions and more, as we review a clinical trial on ProLon to determine if the plan can cause weight loss. We'll compare its weight loss effects to other popular weight loss meal programs.

We'll also review the ingredients in a ProLon meal to give our take on whether or not the program is healthy, and feature unsponsored ProLon customer reviews including a before-and-after video.

Does ProLon Cause Weight Loss?

ProLon is a fasting-mimicking diet, and the brand claims it can cause 5.7 pounds of weight loss in five days.

Fasting-mimicking diets significantly reduce calorie and sugar intake to replicate the metabolic benefits of fasting. A clinical trial published in the Science Translational Medicine journal tested the effects of ProLon on weight.

Trial participants on ProLon lost around seven pounds over three months by using the program for five days of the month.

We will conclude from this research that ProLon is likely to be effective for weight loss.

We commend ProLon for funding legitimate clinical trials published in peer-reviewed journals. This is the gold standard of product research.

ProLon maintains a Science page on their website with links to many other trials showing the positive health effects of ProLon beyond weight.

ProLon vs. Other Diet Programs

ProLon isn't the only diet plan that's been studied in peer-reviewed clinical trials.

An extensive 2016 medical review compared the efficacy of commercial weight loss programs. The study authors reviewed data on Weight Watchers, Jenny Craig, Nutrisystem, MediFast and Optifast.

Jenny Craig was found to be the most effective weight loss program, with an average weight loss 4.9% greater than nutritional counseling alone over the course of one year.

This equates to nine pounds of weight loss for a 200 pound person.

We consider ProLon likely to cause greater weight loss than all of the programs reviewed in this study, given that ProLon caused seven pounds of weight loss in three months, which equates to a potential annualized weight loss of 28 pounds.

We also consider ProLon to be healthier than Jenny Craig, because ProLon provides mostly whole food ingredients and Jenny Craig meals are more "processed."

Based on the existing research, we would recommend ProLon over other commercial diet programs.

ProLon Before and After Video

One of the most popular questions consumers have about any diet plan is: what do real users look like before and after?

Thankfully, a YouTube creator named Zoe Miyoko tried ProLon and shared before-and-after images. We've timestamped the below video to start at the before-and-after section:

Is ProLon Healthy?

The above ingredient label is from the Nuts & Honey flavor of ProLon's Intermittent Fasting Bar.

This bar is much healthier than the average protein bar. It's rich in whole food ingredients like pecans which are clinically shown to be associated with improvements in cardiovascular health, and is naturally sweetened with honey which is clinically shown to be associated with positive body weight outcomes.

Natural flavor is the only ingredient we recommend avoiding, because as we documented in our review of another nutritional brand called Pruvit, there is some medical research suggesting that natural flavoring agents may be harmful to human health.

Since our initial publication of this article, ProLon improved the healthiness of this bar by removing citric acid, which can be pro-inflammatory.

ProLon has a Nutritional Fact Information page on their website with Nutrition Facts labels for all of their products. For the most part, their food products are sourced from whole food ingredients and we consider them to be healthy and nutritious.

All ProLon soups are composed entirely of whole food ingredients and we recommend any of their soups from a nutritional perspective.

The soups are formulated with a plant base like butternut squash, and contain spices such as oregano, garlic and chives.

Overall, we consider ProLon's ingredients to be healthier than most diet plans we've reviewed on Illuminate Health, but we recommend checking the label information and avoiding products with citric acid or natural flavors.

Real People Try ProLon

One of the most popular YouTube reviews of the ProLon diet is published by a creator named Jason Sani. He shares his experience and results on the ProLon diet:

A YouTube creator named Megan Lyons did a five-day walkthrough of the ProLon diet:

Is Fasting Healthy?

At this point in the review, readers are likely wondering whether traditional fasting (rather than a "fasting-mimicking diet") is healthy, and whether it can also cause weight loss.

A 2021 medical review examined data from clinical trials on various types of fasting, from standard fasting to intermittent fasting to the “5:2 diet" (which entails fasting for two days of the week).

The researchers found that fasting had favorable effects on insulin resistance and blood pressure, and also caused weight loss in overweight and obese patients. 

As we explained in our DoFasting supplements reviews article, there is medical evidence that intermittent fasting causes weight loss irrespective of calories consumed, because of favorable metabolic changes.

Fasting is a slight stressor to the body which can cause epigenetic changes that improve health. It’s also logical that the human body would be evolved to adapt to variable periods of fasting, because humans did not evolve with constant access to food.

Intermittent fasting, which refers to fasting for a fixed period of hours per day (typically 16), is effective for weight loss.

A meta-study examined data from 27 clinical trials on intermittent fasting and weight loss.

In every single trial, participants lost weight. The amount of weight lost relative to baseline weight ranged from 0.8% to 13%, but the trials were all short in duration, ranging between 2 and 26 weeks. These are incredibly impressive results.

We would recommend that patients speak with a doctor prior to fasting, because it may not be safe for everyone. However, this data suggests that consumers on a budget may want to consider simply fasting instead of paying for ProLon.

Our Clean Weight Loss Picks

Ceylon cinnamon was described as "an effective anti-obesity agent" in a 2022 meta-analysis. The study authors concluded that effects were greater at doses at or over 3 grams daily.

Illuminate Labs Ceylon Cinnamon Extract is our standardized Ceylon cinnamon supplement which is third-party tested to ensure purity and potency.

Dietary fiber was shown in a medical review published in The Journal of Nutrition to cause 16 pounds of weight loss in 6 months when combined with moderate caloric restriction (750 calories per day below baseline).

MBG Organic Fiber Potency+ is our top fiber pick because it's certified organic, provides 7 g of fiber per serving and costs under $1.85 per serving at the time of updating this article.

Both of the products mentioned in this section are entirely free of additive ingredients that we consider to be unhealthy.

ProLon Pros and Cons

Here are the pros and cons of the ProLon diet in our opinion:

Pros

• Healthy meals
• Fasting has metabolic benefits
• Brand funds clinical trials published in peer-reviewed journals
• Clinically shown to cause weight loss
• More effective than other diet programs
• Brand improved healthiness of some meals since our initial review

Cons

• Some products contain questionable additives
• No proof of efficacy over regular fasting

Conclusion

ProLon has published convincing clinical evidence that the fasting-mimicking diet they developed has similar metabolic benefits to fasting. 

The ProLon diet plan is proven to cause weight loss, and appears to be more effective and healthier than other commercial diet programs such as Nutrisystem and Jenny Craig.

We cannot identify any clinical studies showing that ProLon is more effective than intermittent fasting, or than regular fasting, so simply fasting without a program (but with a doctor's approval) may be the best option for consumers on a budget looking to lose weight.

For the most part, ProLon meals are nutritious and well-formulated. They're rich in nutrient-dense whole foods, and the brand has improved the healthiness of some of their meals since our initial publication of this article.

For consumers who are set on using a commercial diet program, we recommend ProLon over the alternatives.