You are here

New Dietary Guidelines: Some Improvements but Also Fatal Flaws

As expected, the nutritional guidelines for 2015-2020 thankfully excised the long-standing warning against cholesterol-laden food in the wake of several decades of research demonstrating that the original warning was neither based on scientific evidence. However, the updated guidelines still advise Americans limit saturated fat and, in attempt to push Americans toward a plant-based diet, limit meat consumption. The consequences of such advice might not only fail to improve Americans’ diets, but may exacerbate the obesity problem in America.  

While stopping short of recommending that Americans eat a plant-based diet for the health of our bodies and the environment (a proposed recommendation that set off a bit of a firestorm), the recommendations only implicitly advise people to eat less meat (using the euphemism of “saturated fat” and protein) and explicitly advise we eat more vegetables and other “under-consumed food groups.” While the recommendations aren’t as strong as some would like, there’s definite message within them: animal products and processed foods are bad, vegetables and fruits are good.

That message isn’t terrible. Americans could definitely stand to add more vegetables into their diet. But there’s a fundamental calculus that the dietary guidelines, and in fact most government nutritional advice, seem to not understand. There are only three fundamental macronutrients: fat, protein, and carbohydrate. To reduce one, you must increase one or both of the others. Vegetables are awesome (I’m a pescatarian myself), but they are also expensive and time-consuming compared to other kinds of meals. If HHS and USDA are sending the message that animal products (fat and protein) should be reduced what are Americans most likely to replace those calories with? The hope, of course, is that plant-based foods will replace meat calories, but it is easier and cheaper for families to replace them with carbohydrates. 

While many assume that Americans eat more meat today than ever before and that this is a driving factor in obesity, this is incorrect. Our ancestors in the 19th century ate almost twice as much meat as we do today. In 1851, Americans ate between 150 and 200 pounds of meat per person per year (even slaves were allocated an average of 150 pounds of meat a year). Compare that to the 100 pounds of meat the average American adult eats now. The dietary recommendations advise that when we do eat dairy, it should be reduced fat and when we eat meat we should eat “lean,” meaning poultry or meat with fat trimmed off. However, Americans in 1851 almost never ate chicken or turkey, which were seen as “luxury” meats eaten only on special occasions. On the other hand, of the 100 pounds the average American eats today, about half is poultry. So, Americans now are eating half (or less) the amount of red meat as Americans in the 19th century and yet we are obese.

It’s not just anecdotal evidence that shows this bullseye on saturated fat may be misplaced, research is beginning to refute the old adage of animal fat as heart-unhealthy. In 2014, an international study led by the University of Cambridge analyzed data from existing cohort studies and randomized trials on the association between fatty acid intake and coronary risk. They found that not only was animal fat weakly associated with coronary risk, but dairy fat was associated with reduced risk of cardiovascular disease.

On the other hand, replacing total fat in the diet with carbohydrates does not reduce the risk of cardiovascular disease—as the nutritional guidelines admit. Despite this, Americans are eating more carbs, about 25 percent more than we were in the 1970s. And still, we are obese.

Beyond the focus on saturated fat, the guidelines also target “added sugars.” Presumably, they are targeting added sugars instead of total sugars to encourage people to consume more fruit and less soda and candy. However, as I’ve written before, convincing Americans to avoid only added sugars could lead to a trend similar to the “low fat” “fat free” craze of the ‘90s, which did not lead to healthier people—just better sales for clever food marketers.

So, while it’s nice to see that some of experts on the advisory committee were able to set decades of dogma aside and base their recommendations on science—at least when it came to cholesterol—the bottom line is that government dietary advice is still not worth heading. Perhaps 30 years from now they will have stopped harping on about saturated fat and realized that advice on sodium intake is functionally useless, but I hope nobody is holding their breath.