Cairo. Expect a Miracle.

The Mundane Miracle of Intermittent Fasting

The expectations are high. We are seeing some tantalizing research on the potential benefits of intermittent fasting. But as yet, we’re not seeing much in the way of definitive data on its effectiveness for delivering objective clinical outcomes.

In fact, the latest controlled clinical trial paints the picture of a rather mundane miracle. In a 50-week randomized, controlled trial, a 5:2 intermittent fasting diet yielded no better results than a continuous program of calorie restriction. Intermittent fasting worked just as well as a more conventional diet, but no better. Ruth Schübel and colleagues published these results in the American Journal of Clinical Nutrition last month.

Ardent Fans

We hear from ardent fans – both lay people and scientists – making big promises. Jason Fung is selling a slew of books that promise the answer to obesity, diabetes, and longevity lies with intermittent fasting. However, the only peer-reviewed studies we can find from Fung are a few case reports.

Tell them that the data is thin and they will cry foul. “I’m being attacked again,” tweets Fung when someone suggests a few case reports are not enough to “change everything” about managing diabetes.

Tantalizing Possibilities

Make no mistake, some of the preclinical science on intermittent fasting is indeed tantalizing. Scientists see the possibility of better metabolic function, better insulin sensitivity, and healthier aging. These are potential benefits – not yet proven clinical outcomes.

It’s important to remember this: many great ideas that never worked out are littering the landscape of clinical research.

Thin Data on Outcomes

So far, the data on clinical outcomes is thin. A review by Michelle Harvie and Anthony Howell tells us that intermittent fasting has potential clinical value and deserves further rigorous study. We simply don’t yet know what the best approaches are and what the long-term outcomes will be, they say. It might be a dud, it might be amazing, or it might be something solid but mundane.

This is why the ardent fans promising miracles from fasting are not helping themselves – or the prospects for this type of intervention. When you promise miracles and deliver only solid progress, disappointment is inevitable. And that would be a true shame.

Click here for the study in AJCN and here for the narrative review by Harvie and Howell. For further perspective from The Conversation, click here.

Cairo. Expect a Miracle. Photograph © Kevin Schraer / flickr

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December 30, 2018

5 Responses to “The Mundane Miracle of Intermittent Fasting”

  1. December 30, 2018 at 8:16 am, Kashif Ansari said:

    intermittent fasting works since it mimics what our early paleo ancestors faced so often. they didn’t get regular meals which they stuffed themselves with. many days there was starvation and no food in the pot on the fire. then when they caught some wild game and thus got lucky so to say there was a time of feasting. the body was thus subject to an erratic and unpredictable eating schedule that kept it on its toes. it was binge and fast which was an ideal combo for metabolic boosting and body cleansing respectively. with today’s constant supply of plastic food and raiding the refrigerator every chance we get, is it any wonder that we are getting fat. we have lost that one essential quality of man and that is patience. there are a hundred million things to do in life and food is just one of them. why get fixated on food alone.

  2. December 30, 2018 at 8:24 am, Ted said:

    Thanks for sharing your beliefs.

  3. December 30, 2018 at 7:22 pm, John DiTraglia said:

    it doesn’t help with losing weight but being hungry once in awhile and losing weight and then putting it back on and maybe it’s easier to starve yourself once in awhile than to be miserable forever constantly all might be good ideas

  4. January 07, 2019 at 5:18 am, Tass said:

    In terms of sticking to a diet 2 days fasting/low calorie may be better tolerated in some people compared to continuous dietary restriction so there might be a key benefit. It’s never 1 diet fits all. Understanding the defining characteristics of those who do well on a particular diet should be also be considered.

    Its accepted that many of the positive outcomes of intermittent fasting (including on blood biomarkers, longevity and neurocognitive outcomes) have been in animals but studying these long term outcomes is obviously difficult in humans.

    So far the preliminary studies are promising but but obviously we need larger controlled and randomized clinical studies.

    We must be patient!

  5. January 07, 2019 at 6:04 am, Ted said:

    Thanks for sharing your very thoughtful comments, Tass.