Read Original Release

Unfounded claims dog news release on ‘fasting-mimicking diet’


1 Star

Scientifically-designed fasting diet lowers risks for major diseases

Our Review Summary

This is a news release marked by extravagant claims but a surprising lack of numerical data to back up those claims. It did not score well on our 10 systematic review criteria.

It’s about a small study of 100 people that looked at what happened if they consumed a low-calorie (between 750 to 1,100 calories per day) pre-packaged diet kit for 5 days intermittently over 6 months. The news release suggests that this regimen might lower the patients’ risks of “cancer, diabetes, heart disease and other age-related diseases.” While the release says at the top that the trial “demonstrated a host of benefits” and later “that the diet is feasible, effective and safe for humans,” it says in the next line that larger studies are needed to confirm its effects.  So which is it?  Did it demonstrate effectiveness? Or is that an effect that needs to be confirmed?  The words matter, and can be misleading.

The news release alternated between caution and lack of discretion in describing the actual known outcomes of the diet. A study author is quoted saying the study did not prove a lowering of risk, but the news release ignores that warning and claims a risk-lowering was “demonstrated” by this early study.

One positive note: The release is to be commended for being transparent about potential conflicts of interest.


Why This Matters

Being precise in news releases matters because precision or the lack of it affects what the public learns about health and diet strategies. This news release suggests a proprietary pre-packaged diet lowered risk of a wide range of serious diseases, but the study carefully states it proved only “safety” in a very small group of people.

This is just the sort of exaggeration that reduces public trust in reports about health and diet, by over-promising and mistaking the measurement of certain endpoints, such as blood pressure or blood biomarkers, with a larger concept such as reducing risk of disease in the long-term. has seen this pattern repeated so often we have added a page in our toolkit about referencing surrogate endpoints instead of actual health outcomes. For example, an intervention may affect a person’s blood pressure, but that doesn’t mean it decreases their risk of heart disease.

It takes much larger and longer studies than the one described in the news release to reach the proof of effectiveness that matters most.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

While the release discloses that meals during the low-calorie diet periods were provided by a nutrition company, there is no discussion of the cost of following this special diet. We thoroughly scoured L-Nutra’s pages describing the ProLon meal kits containing “proprietary plant-based soups, bars, drinks, snacks, herbal teas, vitamins, and supplements” but no costs were to be found despite the site claiming the meal kits are available. The site invites potential customers to create an account and request more information.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

This release reports only surrogate or intermediate endpoints of disease risk, not a change in disease risk itself. For example, changes were reported in blood pressure, waist circumference, and body weight in participants after three fasting diet periods, which the release equates with a reduction in disease risk. However, measuring surrogate endpoints or disease biomarkers without looking at actual disease incidence is not a measure of individual health outcomes. To do this, researchers would need to measure endpoints like the number of cardiovascular events that occurred during or after the study or the number of people diagnosed with diabetes — which requires much longer than a few months of follow-up.

Some of the claims made in the release were inappropriate. For example, “In effect, the diet reduced the study participants’ risks for cancer, diabetes, heart disease and other age-related diseases, according to the findings published Feb. 15 in Science Translational Medicine.”

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

There is no mention of any potential side effects. Certain people may not be ideal candidates for an extreme low-calorie diet, even intermittently. The release does not comment on this.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release clearly exaggerates the evidence and we describe this in detail under the Unjustifiable Language criterion section below.

The study on its own has credible and well-described evidence for its limited claim of a change in blood pressure, C-reactive protein and other markers that may signal a lowering of risk for heart disease. But the release fails because it claims these prove a reduction in risk of disease.

Study author Longo is quoted saying: “Larger FDA studies are necessary to confirm its [the diet] effects on disease prevention and treatment.” In this instance he acknowledges that the small study does not prove a permanent lowering of risk. Yet the release repeats several times that the diet does lower risk.

Does the news release commit disease-mongering?

Not Satisfactory

There is no disease mongering, but there is also no context provided on how fasting fits into current diet and nutrition recommendations, or which segment of the population might benefit from such a diet.

Does the news release identify funding sources & disclose conflicts of interest?


We applaud the release for including detailed information on the financial conflicts of the lead author and the University of California at Davis. Here is how the release disclosed the financial conflicts:

“Longo is the founder of L-Nutra, whose food products were used in the study. His interest in L-Nutra has been disclosed and managed per USC’s conflicts of interest policies to assure objectivity and a lack of bias in the conduct and reporting of his research.

USC also has an ownership interest in L-Nutra, and the potential to receive royalty payments from L-Nutra. USC’s financial interest in the company has been disclosed and managed under USC’s institutional conflict of interest policies.”

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

The release does not include any discussion on how people can manage long-term health risks through many other kinds of diets, exercise or medications to lower blood pressure. Even one line on such alternatives would have satisfied this criterion.

Does the news release establish the availability of the treatment/test/product/procedure?

Not Satisfactory

The release does not explain whether materials used in the clinical study are widely available. The product website, however, is actively promoting the kits.

Does the news release establish the true novelty of the approach?

Not Satisfactory

The release states that this is the “first randomized clinical trial with enough participants to demonstrate that the diet is feasible, effective and safe for humans.”

The diet being tested is named by the researchers as a “fast-mimicking diet” or FMD.

While this may be the first test of a “fast-mimicking diet” reliant on the ProLon diet kit, the concept of very low-calorie diets is not new and there are hundreds of clinical trials that have delved into reducing risk for cardiovascular disease via diet. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) discusses very low-calorie diets on its web page.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

The release doesn’t engage in sensational language but its headline is problematic. It promises that a diet lowers risks for major diseases. A researcher later contradicts that claim by saying this early study only shows safety.

“But this is the first randomized clinical trial with enough participants to demonstrate that the diet is feasible, effective and safe for humans.

Larger FDA studies are necessary to confirm its effects on disease prevention and treatment,” he added.”

Calling for “larger FDA studies” may also be misconstrued by some readers. The FDA does not conduct clinical trials. Rather, it has internal and advisory experts that assess the validity of trials as part of its approval process.

Total Score: 1 of 10 Satisfactory


Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.