What Happens When Prevention Outcomes Contradict Beliefs?

Archangel, study for the Foundation of FaithThe Obesity and Energetics Offerings from the Indiana University School of Public Health and the University of Alabama at Birmingham NORC certainly got our attention this week with an entry titled “Cherished Hypotheses Meet Hard Facts.” That entry links us to two new systematic reviews of randomized controlled trials to assess prevention of obesity in youth. Outcomes from these two reviews seem to contradict some fundamental beliefs about obesity prevention in young persons.

They conclude that diet and exercise interventions for children and adolescents make little or no difference in their risk of obesity.

Faith in Diet and Exercise

The belief that diet and physical activity interventions are effective for preventing obesity is more than a hypothesis for many people. It better fits the definition of an article of faith.

CDC is unambiguous about it:

“Schools are a priority setting for obesity prevention efforts because they reach the vast majority of school-aged youth, provide regularly scheduled opportunities for physical activity, and offer nutritious foods through school meal programs.”

Systematic Reviews Raise Doubt

The new publications come from the Cochrane Database of Systematic Reviews. Cochrane is a nonprofit organization with global reach which aims to set a high standard for evidence-based medicine. Cochrane reviews use explicit methods to minimize bias and random error, and adhere to some of the highest standards for health science.

The first of these two reviews addresses obesity prevention interventions for children from the age of 5 to 11. The setting for most of the interventions was schools – the CDC priority. The authors conclude:

“The body of evidence in this review demonstrates that a range of school‐based ‘activity’ interventions, alone or in combination with dietary interventions, may have a modest beneficial effect on obesity in childhood at short‐ and medium‐term, but not at long‐term follow‐up. Dietary interventions alone may result in little to no difference.”

The second analysis, for interventions in adolescents, reached similar conclusions:

“The evidence demonstrates that dietary interventions may have little to no effect on obesity in adolescents. There is low‐certainty evidence that activity interventions may have a small beneficial effect on BMI at medium‐ and long‐term follow‐up. Diet plus activity interventions may result in little to no difference.”

It’s Complicated

Unfortunately true is the observation that nuance doesn’t sell. And there are few problems more nuanced than the rise of obesity – the most prevalent chronic disease in the world. So blind faith in broad generalizations about healthy eating and active living to prevent obesity will get us nowhere. Progress will only come from a deeper understanding of all the factors that are driving global populations to ever more obesity of greater severity.

Food and physical activity are important, but they do not tell the whole story. Not by a long shot.

Click here and here for the new Cochrane Reviews. For more about the nuance and complexity of obesity, click here and here.

Archangel, study for the Foundation of Faith by Nikolaos Gyzis / WikiArt

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June 2, 2024

8 Responses to “What Happens When Prevention Outcomes Contradict Beliefs?”

  1. June 02, 2024 at 6:35 am, Jon Walker said:

    So what’s next then …
    Nothing makes a difference?
    I gues not, it’s up to individuals if they want to try and stop it themselves. Parents included.
    Diet drugs for all perhaps though rather expensive and not a panacea either.


    • June 02, 2024 at 7:25 am, Ted said:

      What’s next should be genuine curiosity about finding more effective interventions that address more than diet and exercise in isolation. Soon even the most zealous advocates for the historically narrow approach to obesity prevention will wake up to the futility of pushing the same ineffective agenda repetitively.

  2. June 02, 2024 at 10:56 am, Lisa said:

    I feel truly sorry for any that follows the guidelines, which are riddled with conflicts of interests and favor industry, NOT health. Our lives are surrounded by environmental toxins, constant stress, tainted food and water, and disconnection from nature and each other. Is anyone surprised that the children school “food”(which included Lunchables) and “exercise” programs don’t produce good results?


    • June 02, 2024 at 2:05 pm, Ted said:

      While you contemplate conflicts of interest, Lisa, spare a thought for folks who make a career out of research or delivery of diet and exercise interventions to prevent obesity. It is easy to find conflicts and biases that we all have and very hard to purge them. I hope for greater wisdom for discerning where the high quality evidence is pointing us.

  3. June 02, 2024 at 12:00 pm, Richard Atkinon said:

    This comes as no surprise to unbiased scientists who follow facts, not optimistic shibboleths. Thousands of studies of studies on PubMed demonstrated that simple diet and exercise do not work long term for adults. Why should it work for kids? The idea that basic human physiology is different in adult and kids is fanciful. Hunger is a very disruptive human condition and people won’t stay in it for long. Ted identifies the critical question – why do some people, adults and kids, become obese and their physiology changes to keep them obese? Maybe it is environmental chemicals, maybe adenovirus 36 or other viruses, or maybe something of which we have no clue as yet. It would be helpful if granting agencies stop funding D&E studies that don’t work and fund some creative ideas. For skeptics, note that today, PubMed identifies 12,049 studies using the search terms “diet & exercise & obesity & treatment – none of which show a significant long term effect on obesity.


  4. June 02, 2024 at 8:40 pm, John Dixon said:

    No one who has watched the literature over decades could be surprised by these results. Indeed, most are so committed to myths and beliefs that they are blinded to alternative hypotheses, and numerous other targets have been ignored.


  5. June 04, 2024 at 9:49 am, John DiTraglia said:

    The nuance is – diet and exercise is good for you. The hard science is – it’s a lie to you tell anybody it will help change your weight or shape.


    • June 05, 2024 at 3:32 am, Ted said:

      Exactly right, John.

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