The committee charged with revising the Dietary Guidelines for Americans appears to be ranging far from its original mission of determining the best foods to keep us healthy.

In early 2011, USDA and the Department of Health and Human Services released its new, improved 2010 dietary recommendations. In announcing the release, then-HHS Secretary Kathleen Sebelius and USDA Secretary Tom Vilsack stated that, “Because more than one-third of children and more than two-thirds of adults in the United States are overweight or obese, the 7th edition of Dietary Guidelines for Americans places stronger emphasis on reducing calorie consumption and increasing physical activity.”

What’s wrong with that? Answer: Absolutely nothing. That is sound advice, a positive health message that is data-driven and evidence-based (government-speak for a proposition that has at least some facts to back it up).

Reducing calories — when many people are overeating, even is doing so unconsciously — makes sense, and it’s a relatively straightforward proposition. Not easy to do, but certainly not complex: Cut down on high-calories snacks and fast-food, and don’t pile seconds (or thirds) onto your plate at home.

Pretty simple.

Likewise, “increasing physical activity” is also a total no-brainer. Hardly any of us actually spend the requisite hour-plus every day engaged in vigorous exercise and/or physical activity that science has shown to be essential for maintenance of optimal health. We’d all benefit by working out or even just walking more than we do.

But every five years the Dietary Guidelines for Americans need to be updated, per congressional mandate. Theoretically, new science on diet and nutrition is always ongoing, and the Guidelines need to reconcile any new research with the basic game plan people are supposed to follow.

Only this time, the Dietary Guidelines for Americans Committee decided that for reasons other than nutrition, new guidance needs to be issued. This time around, the committee decided that “sustainability” should be given credence as a factor in advising the country on what’s included in the optimal diet.

Not for the health of the public, but (allegedly) for the health of the planet.

Misleading data

That’s a bold move that takes the DGAC folks well outside the realm of dietary guidance, and attempts to conflate what we eat with environmental concerns connected with global issues of farm productivity, resource limitations, energy usage and population density. Yes, what we eat has an impact on those issues, but in the absence of clear-cut, indisputable scientific evidence — you, know, like the kind that says human beings need to maintain an active lifestyle — a committee charged with evaluating the science of diet and nutrition ought to stick to their bailiwick.

Because the science that says meat and poultry production is responsible for 15 percent of all global carbon emissions is highly controversial. Not only does lumping all livestock production into one category ignore the fact that there is a huge difference between the typical North American rancher, producers or feeder and nomadic tribes in sub-Saharan Africa herding cattle across thousands of square miles of semi-arid rangeland, or industrial operations in Brazil that slash-and-burn rainforests to expand cattle and feed crop production.

They’re not at all the same, either in terms of efficiencies, energy consumption or impact on carbon production.

Equally important, none of the do-gooders (like the Dietary Guidelines folks) carping about meat-eating ever factor in the substitution of plant-based protein for all the meat, poultry and dairy products they want to eliminate. It’s not possible to issue bland assurances that eating less meat automatically reduces the global food industry’s carbon footprint when most of those calories would need to be replaced by plant-based sources that require land, water, fertilizer and energy inputs, all of which impact carbon emissions.

Finally, although I’m confident most readers who spend time on this site are well aware of consumption data, it’s about time to change the calculus. When vegetarian proponents, and by extension their eco-advocate brethren, point out the “excessive” amounts of meat and poultry consumed by Americans — which is the basis for the DGAC members feeling confident that calling for a reduction in the consumption of animal foods wouldn’t case any nutrition-related problems — they use disappearance data.

When, for example, media report that “Americans consume more than 200 pounds of meat and poultry a year,” that number is arrived at by totaling annual slaughter numbers and simply dividing total tonnage by total population. That doesn’t account for plate waste or cook shrinkage, both of which are significant numbers. Nor does an average number represents what the majority of real people eat, any more than “average income” calculated by lumping billionaires in with wage-earners provide a realistic idea of actual incomes.

In both cases, more accurate data would be obtained by calculating the median number of pounds per year, a total that is right in the middle of the extremes of either no meat at all or meat-at-every-meal consumption.

I realize most folks in the industry know this. I’m not mentioning the difference between disappearance and consumption data as a tutorial, only as a reminder that the explanation needs to be part of any conversation about the optimal levels of meat and poultry.

The point being, we’re not eating anywhere near the amounts of animal foods activists always try to claim, thus statement regarding the utility of decreasing the consumption of such foods needs a proper context.

And a framework based on sound nutritional science, not policy positions based on political posturing.

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.