Time to Redesign the Process for Dietary Guidelines?

Nutrition science is hitting some hard limits. Diverse scholars say those limits are hurting its credibility and relevance. On top of that, the National Academies says the process for updating dietary guidelines needs a makeover. But at the same time, USDA is drawing fire for a former food industry lobbyist who may guide that process.

So it’s hard to tell if this process will get better or worse.

Transparency, Rigor, and Systems Science

The National Academies issued an exhaustive consensus report last fall. In response to controversies, Congress mandated the report. It identified three areas of focus for improving the process that produces new dietary guidelines every five years.

Better transparency is essential for building public trust in the guidelines. Good luck with that one. Especially with a food lobbyist guiding the process, it seems a lofty goal. But the problem is much bigger than the food industry. Everyone has passionate ideas about nutrition. Some of those spring from personal faith and philosophies. Some of them flow from a person’s vocation. But all of those passions set up biases and conflicts of interest. Unfortunately, most people operate from a very narrow definition of bias and conflicts. It leaves them blind to pervasive biases.

Better scientific rigor could strengthen the evidence base. Best practices for systematic reviews and sound methods are hot subjects for debate. Nutritional epidemiology takes a hit for weakness in drawing conclusions about causality. But some stakeholders also dismiss traditional experimental methods. They view them as too rigid to be relevant to the complex systems driving human nutrition and health.

To cope, the Academies report calls for applying systems science. It says current methods for naming nutrients of concern is inadequate. So we have lingering debates about healthy fats, added sugar, and meat.

Asking Too Much?

One question remains. Are we asking too much? Will USDA and HHS – the agencies that together issue these guidelines – ever release guidelines that fully satisfy their diverse stakeholders?

Food activists want a process untouched by the industry they deride as big food. The food industry takes exception and expects a seat at the table. And excluding legitimate stakeholders never ends well. Everyone – not just industry – brings a bias to this table.

And speaking of bias, we wonder about the bias baked into this task. Many stakeholders think dietary guidelines should solve our problems with obesity. But that might be a triumph of fantasy over reality. The first ever dietary guidelines came into being at the same time obesity prevalence started to grow. Guidelines keep getting refined. Obesity rates keep going up.

Surely that’s not cause and effect. Surely, though, it’s not very encouraging.

Click here for the National Academies report and here for more on limitations of nutrition science. For perspective on evolution of dietary guidelines, click here.

Light People, photograph © Sam Javanrouh / flickr

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February 25, 2018