Puff Pastry

Puffery and Promise for Intermittent Fasting

FNCE served up a little nutrition epistemology in Washington yesterday. How? John Trepanowski and Steve Anton explored the promise and the puffery of intermittent fasting. RDN Carolyn O’Neil moderated. They explained some solid science. But they exposed some appalling hype.

What do we really know to be true? Versus what is mere speculation or opinion. That’s what epistemology is all about. And fortunately, Trepanowski is an expert on the subject.

Curing Diabetes with Puffery

As if to set the stage for this debate, Jason Fung sent out some absurd hype last week. He published a report on three patients with type 2 diabetes in BMC Case Reports. To call it a study is misleading. It’s a case report. Thee patients. No controls. But the lack of meaningful evidence did not deter him. Fung told Healthline:

This study shows that a dietary intervention – therapeutic fasting – has the potential to completely reverse type 2 diabetes, even when somebody has suffered with the disease for 25 years. It changes everything about how we should treat the disease.

Maybe Fung is willing to change everything he does based on short-term, uncontrolled observations of only three patients. But serious clinical scientists want no part of it. Matthew Freeby is associate director of UCLA’s clinical diabetes programs. He said:

It’s potentially dangerous to tell patients their diabetes has been reversed, because one is always at risk for progression.

Registered dietitian Raquel Pereira was even more blunt. She called Fung’s claims “insulting” to people with diabetes. The research is minimal and doesn’t justify such sweeping claims.

Promising, But Incomplete Science

Back at FNCE, we witnessed a debate that was much more reasonable. Trepanowski and Anton are two careful scientists. They offered up reasons to have high hopes for intermittent fasting. But the debate made the limitations clear. It can be a challenge to persist with fasting over the long term. And the evidence base is incomplete.

The animal data is impressive. Some of the human data is encouraging. However, we don’t have the evidence to say what is the best regimen for good adherence. And we certainly don’t have comparative outcome data. At the end of the day, what we have is intriguing and incomplete science.

So when someone tells you they have the answer based on just three patients, rest assured. They’re overselling it.

Click here for more on the debate. For two systematic reviews, click here and here.

Puff Pastry, photograph © Mattie Hagedorn / flickr

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October 22, 2018

9 Responses to “Puffery and Promise for Intermittent Fasting”

  1. October 23, 2018 at 2:21 am, Mark Wilson said:

    IF has been used on Dr Fung’s IDM programme with diabetics for many years and by many other Doctors. Are you sponsored by Insulin manufacturers?

    • October 23, 2018 at 4:00 am, Ted said:

      Nobody sponsors, censors, or approves what we write at ConscienHealth. And Mark, the plural of anecdotes is neither data nor evidence.

  2. October 24, 2018 at 10:23 pm, e funk said:

    Puff pastry recommended for Type 2 Diabetes?

    • October 25, 2018 at 12:35 am, Ted said:

      Ha! No dietary recommendations here. Best to consult a dietitian.

  3. October 26, 2018 at 12:33 am, Jonathan said:

    In one recent report on your site, this challenge is set forth:

    “In other words, it’s time to rethink obesity and come up with fresh strategies that will actually work. It’s time to test our sacred assumptions.”


    Yet in this more recent article, someone who is doing exactly that is being attacked, despite the fact that there is much more than a three-person case study to support the efficacy of intermittent fasting (IF) in improving outcomes for obese and Type 2 patients. I am admittedly conflating obesity with Type 2 diabetes, but hopefully it’s not a matter of controversy here that one leads directly to the other.

    Perhaps it’s time to take some of your own advice, and follow this report with one based on a more nuanced take on IF apart from criticism of Dr. Fung, who, while clearly an evangelist, is one for a treatment that is free, time-honored, and demonstrably benign when administered under supervision. One wonders if at least some of the resistance to IF may be the fact that it won’t generate revenue for stakeholders.

    • October 26, 2018 at 1:27 am, Ted said:

      Thanks, Jonathan, for taking the time to comment. And thanks for making it clear that you understand Dr. Fung is an evangelist. Evangelism and science are different pursuits.

      Intermittent fasting definitely has promise. There’s no attack here on Dr. Fung. But good science is necessary before making broad recommendations about its application for treating type 2 diabetes.

      It’s also worth noting that Dr. Fung is in the business of selling his clinical services and his books. There’s absolutely nothing wrong with that. But it does give him a financial interest in promoting his point of view. That’s why relying on real clinical data, not anecdotes, is important.

  4. October 26, 2018 at 1:32 pm, Greg said:

    Thank you for pointing out that the difference between randomized clinical trial level data and case reports in self-selected patients without controls.

    I also appreciate you mentioning that regardless whether your funding comes from clinical revenues or drug companies or the NIH (folks sometimes leave this one out), we all have biases and potential entanglements. Properly powered, randomized and if possible blinded clinical trials help offset those possible biases.

  5. October 26, 2018 at 2:37 pm, Tatiana Zilberter said:

    Ted, “the plural of anecdotes is neither data nor evidence” – are studies into mechanisms of IF and TRF – data? They are plenty and they are indeed promising

  6. October 31, 2018 at 3:05 am, Angelo Polytiras said:

    I was diagnosed with diabetes(type 2 ) 3 years ago .I started a high fat low carb diet with intermittent fasting ,just what Dr Fung decribes in he book “The obesity code ” . I have lost over 110 pounds (53kgs) and my diabetes has been reversed. I have not been cured because I am sure if I start eating the way I use to it will (diabetes ) return .
    The best part is that I am full of energy and the weight has stayed away !!