Ad Hominem ad Nauseum

Argumentum ad hominem is a logical fallacy that has no place in science, but unfortunately is all too common in health, nutrition, and obesity policymaking. The most recent example comes from sensational UK media reports critical of an eminent nutrition scientist — Ian Macdonald — for advising both food companies that sell sugary products and the UK government on sugar-related health issues.

In one report, Simon Capewell, an advisor to the advocacy group Action on Sugar, commented on Macdonald’s perceived conflicts, saying, “It’s like putting Dracula in charge of a blood bank.” But the Chair of Action on Sugar, Professor Graham MacGregor, declined to comment on Macdonald. He said, “Action on Sugar also works with the food industry but we don’t stand any nonsense from them.”

The UK Department of Health defended Macdonald: “Professor Ian Macdonald has fully declared his conflicts of interest in accordance with the Code of Practice. He is a highly respected figure within the public health community and has made a valuable contribution to research into obesity and nutrition.

An ad hominem attack is typically utilized to compensate for weak evidence behind a proposition someone is trying to advance. It is an obnoxious distraction. The real need is for integrity in research, acknowledging all sources of bias, and addressing inevitable biases through scientific rigor, not ad hominem fallacies.

It’s hard to imagine a worse idea than discouraging public health and nutrition experts from offering their best advice to companies who make the food we eat. But ad hominem attacks on those who do so might have just that effect.

Click here to read a sensational report from the Daily Mail, here to read more from Food Navigator, and here to read more on truth, bias, and conflict in nutrition and obesity research.

The Angry One, Oil painting by Ferdinand Hodler / WikiPaintings

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.


4 Responses to “Ad Hominem ad Nauseum”

  1. January 22, 2014 at 8:45 am, Leoluca Criscione said:

    … I would not exclude the possibility that he advices the company on how to make their products “healthier”! This wouldn’t be even a conflict of interest!!!!

    • January 22, 2014 at 2:17 pm, Ted said:

      Agree. I would both hope and expect that to be true.

  2. January 24, 2014 at 7:53 am, Yoni Freedhoff said:

    Ad hominem is a bad thing no doubt.

    But so too are straw man arguments.

    The concern regarding Simon Capewell is not, as your article suggests with this statement, “It’s hard to imagine a worse idea than discouraging public health and nutrition experts from offering their best advice to companies who make the food we eat”, about him offering advice to the food industry, it’s about him chairing a committee whose job it is to provide public health policy recommendations for the government and where his employment by the food industry about which he’s supposed to make recommendations no doubt represents a very real, and unnecessary conflict (as surely there are experts whose labs aren’t funded by Mars).

    • January 24, 2014 at 8:34 am, Ted said:

      I understand your perspective, Yoni. It’s also important to understand the difference between being funded solely by Mars and receiving funding from many different sources, including perhaps Mars.