by Marion Nestle
Jul 8 2014

Conflicts of interest in nutrition research

Over the July 4th weekend, a reader sent a link to a paper about to be published in the American Journal of Clinical Nutrition titled Increased fruit and vegetable intake has no discernible effect on weight loss: a systematic review and meta-analysis.

I took a look at the abstract:

Studies to date do not support the proposition that recommendations to increase F/V intake or the home delivery or provision of F/Vs will cause weight loss. On the basis of the current evidence, recommending increased F/V consumption to treat or prevent obesity without explicitly combining this approach with efforts to reduce intake of other energy sources is unwarranted.

This would seem to make some sense, no?  But the dismissal of recommendations to increase fruit-and-vegetable consumption sent up red flags.

My immediate question: who paid for this study?

Here’s the conflict of interest statement.


Note the presence of companies making processed foods whose sales would decline if people ate more F&V.

A coincidence?  I don’t think so, alas.

More evidence: just today, Bettina Siegel sent me her post on a paper sponsored by the Corn Refiners Association, once again with a predictable outcome.

When it comes to nutrition research, “guess the sponsor” is a game that is all too easy to win.

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  • Erica House

    I teach a Research Methods course at a local university and one of the biggest things I stress to my students is when they read about ‘latest research’ in news they need to see who has funded it!

  • Colby

    They do not dismiss increasing F/V intake, in fact in their discussion they note that F/V “promote health in many ways”. They just don’t cause weight loss.

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  • Jessi Silverman

    Could you take a look at this one? I couldn’t figure out who sponsored it, and the results seem very counterintuitive.

  • Zeve

    A recent study was reported in the popular media as supposedly “proving” that drinking Earl Grey tea can be as effective as taking statins. I thought that was odd, so I checked around and found a somewhat more critical summary of the very same study (here: ). Apparently, the study was not a human study but a small rat study, and… the study originated from a region of Italy where the bergamot fruit (used to give Earl Grey tea its unique flavor) is a major industry.

  • KentComments

    Yeah, Colby is right: they don’t dismiss increasing intake of fruit & veg, they just conclude that “recommending increased F/V consumption to treat or prevent obesity without explicitly combining this approach with efforts to reduce intake of other energy sources” won’t work — based on the evidence. F&V don’t have to be able to solve all nutritional problems to be worthy of promotion.

    And per their suggestion that to make it work we’d have to explicitly counsel and facilitate the concomitant reduction of intake of other foods, and contrary to your worry that companies making processed foods might be trying to undermine efforts to promote F&V out of worry that sales of F&V would displace processed food sales would decline if people ate more F&V, studies have shown that when incentives are used to promote F&V purchases, F&V purchases do go up — but purchase of other foods don’t go down. Eg:

    Epstein LH, Dearing KK, Roba LG, Finkelstein E. The Influence of Taxes and Subsidies on Energy Purchased in an Experimental Purchasing Study.
    Psychological Science. 2010 Mar;21(3):406-14. DOI: 10.1177/0956797610361446

    Kraft, Coca-Cola, et al are perfectly happy for people to eat all the F&V they want. They (rightly) only fear active efforts to discourage consumption of their own product.

  • Marion

    It’s not published yet and seems only to be available to subscribers at the moment.

  • BluebirdofUnhappiness

    But if we don’t make a bad guy in our narrative, where’s the drama? Must keep the audience engaged. Incidently when my spouse cooks, the veggies are drenched in cheese and/or butter, the fruit in sugar. And how many calories in salad dressing? Besides, this is saying adding more raw celery sticks during your buffalo chicken wings and beer snack-a-thon doesn’t make you lose weight, not that eating the celery sticks instead of those doesn’t.

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  • maxasaurusBax

    Glad to see you mention this – I was so puzzled by this paper on Monday. Regardless of who funded it, there are so few studies meeting criteria for analysis I don’t see how it can be called a meta-analysis. The title should not read “no discernible effect on weight loss” but “not enough evidence to measure a potential effect on weight loss.”

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  • School Bites

    Another example of a conflict in interest in nutrition research: the chocolate milk in school study by Cornell Food & Brand Lab…

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  • mem_somerville

    Did you hear the one about the supposed increase in antioxidants in organic vegetables–funded by the organic advocacy group? Yeah.

  • Emily

    Hi Dr. Nestle, although it does seems suspicious that the sponsors of the research are those that wouldn’t benefit from people eating more fruits and vegetables, could you explain how the results of the research might be biased? It seems that the results should just be what they are, no matter the sponsor. Thanks!

  • TR

    The title of the study does not say that therefore it is misleading inspite of what the body of the study states.

  • KentComments

    The title of the study reflected exactly what they found: “Increased fruit and vegetable intake has no discernible effect on weight loss.”

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  • Loren Eaton

    Slippery slope, Erica. So are you also teaching them to set aside their bias (which you seem to be encouraging) and look at the quality of design and data? Does this also mean your students will be more likely to believe the research of someone they ‘like’ due to their political agenda?

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