Don't be fooled, our kids' diets haven't improved "significantly"
Findings from a newly published study in the Journal of the American Medical Association (JAMA) reportedly indicate that there has been “modest” improvement in the diets of American children over the 17-year period from 1999 to 2016.
However, this study appears to contradict the CDC’s data that childhood obesity has climbed from 14% to 18.5% in that same period as well as the research indicating that the incidence of type 2 diabetes among children is on the rise. While these seemingly paradoxical data can technically all be true at the same time, color me skeptical that American kids’ diets are meaningfully—or even modestly—improving.
To interpret for ourselves what the JAMA study really shows, let us scrutinize the scoring criteria, the study’s actual data, and the crafted narrative surrounding the findings.
First, the scoring criteria.
To estimate diet quality, the study uses the Healthy Eating Index (HEI) and the dietary standards put forth by the American Heart Association (AHA). Both the HEI and AHA surveys evaluate a combination of food groups and individual nutrients like saturated fat and sodium from self-reported dietary records.
Perusing through the criteria, I spot a number of issues. For example, per both surveys, 100% fruit juice counts toward one’s daily servings of fruits without any limitation or cap despite the fact that juice and whole fruits do not have equal nutritional value. Given that these surveys are rooted in the USDA Dietary Guidelines (which are a product of industry lobbying), this criterion feels more political than evidence-based.
Unsurprisingly, the other criteria are equally dubious. Case in point: Consumption of processed meat, a known carcinogen, is allowable up to half an ounce per day for full credit on the AHA survey. That’s equivalent to eating two and a half hot dogs or five strips of bacon per week; as a nutritionist I find this wildly excessive for an “ideal” intake. Contrast that with the target intake for legumes, nuts, and seeds at just four servings per week. I would argue for a minimum of at least one daily serving of these plant proteins.
The surveys are flawed not only for what they include but also what they fail to include.
Ultraprocessed foods, which make up more than 50% of the American diet, are not evaluated or scored.
The surveys also fail to discriminate between 100% whole grains and partially whole-grain foods, which could lead to an overestimation of whole grain intake.
On the HEI survey, seafood and plant proteins are categorized together—a mystifying decision by the survey architects; moreover, all “protein foods”—an outdated concept—are lumped together in another category that includes seafood and plant proteins again.
Red meat, poultry, seafood, dairy, nuts, seeds, and legumes simply do not belong in one category!
There are yet more issues with these surveys that, in my opinion, render them ineffective at capturing true diet healthfulness, but for the sake of brevity, let’s move on.
Second, the data.
The study reports an improvement in kids’ diet quality within the range of 11 to 27%. However, looking through the numbers, I believe the data show marginal progress in some areas and potential regression in others.
Before we look at the data, it’s important to note the very large sample size of this study—31,420 kids in total. Due to this large sample size and the way statistical significance is calculated, minor changes in consumption will be deemed “significant” or “real” despite having little to no practical impact on health outcomes. Keep this in mind.
The biggest reported dietary improvement is in the consumption of whole grains, which appears to have doubled from 1999 to 2016. However, the baseline intake was already extremely low at just half a serving per day, so a doubling in this context means kids are now getting just one serving of whole grains per day.
The likely explanation for this increase is that the food companies who produce sugary breakfast cereals and other ultraprocessed grains products have increased their products’ whole grain content, yet these products remain extremely sugar-laden and refined. And, as noted earlier, it is unclear whether or not the survey differentiated between 100% whole grains and partially whole grains. Ultimately, “whole grain” labeling on these products is nothing more than a cynical marketing tactic that has little to no positive effect on kids’ health while kids are still consuming six times as many refined grains as whole grains.
There’s a decent bit of bad news from these data as well.
Consumption of vegetables has not increased. Red meat consumption appears to have declined, but poultry and processed meat consumption have more than taken its place. Moreover, the consumption of cheese (high in saturated fat) and eggs (which contain cholesterol and TMAO precursors) has increased considerably. Although added sugar intake has reportedly decreased, saturated fat, sodium, and cholesterol have all gone up in kids’ diets.
This is where my interpretation of the data diverges most starkly from that of the study’s authors. They see the increased consumption of higher-fat dairy products and other “protein foods” like eggs as improvements despite the fact that the result is an increase in dietary cholesterol, sodium, and saturated fat intake. Personally, I find the positive outlook on these data rather antiquated.
The study reports that the proportion of children consuming “poor” quality diets, defined as less than 40% adherence to the survey criteria, dropped significantly from 77% to 56%. I want to celebrate this change, but due to the many problems I’ve outlined above, I can’t help but be skeptical. From what I see, there have only been marginal improvements in fruit, whole grain, and plant protein, fiber, and added sugar intake while the consumption of animal protein, sodium, saturated fat, cholesterol, and processed meat—all of which are implicated in our crisis of diet-related disease—has gone up.
Is this really the best we can do in 18 years of nutrition and public health advocacy?
Finally, the crafted narrative.
Saying kids’ diets improved by 27% is like saying a change from 2 to 3 is an increase of 50%. Mathematically, they’re both true, but focusing on the percentage devoid of context obscures the reality that we’ve barely made progress in our kids’ diets over the last two decades.
If American children’s diets had truly improved as this study claims, could we realistically have seen incidence of obesity continue to rise since 1999? It is doubtful, and frankly, I believe these surveys are adept at measuring adherence to a set of industry-driven dietary guidelines. And better adherence appears ultimately to not per se lead to better health outcomes for our kids.
This is perhaps why, despite the celebratory rhetoric surrounding the “progress” in our diet quality, a crisis of diet-related disease continues to rage on and worsen among this country’s youth.
The lesson in all of this is that, if we want to be serious about meaningfully improving our kids’ diets, we need higher standards for how we measure diet quality—standards devoid of antiquated elements like “protein foods” and industry-mandated dairy requirements. We need to focus on practical significance as well as statistical significance, which in this case would manifest as a precipitous drop in rates of obesity, pre-diabetes, hypertension, and other diet-related diseases in kids.
As a country, we must marshal our resources to ensure every child has access to a diet rich in plant foods and to reign in large predatory food corporations and lobbies. And, to those scientists who produce research, it is time to stop obscuring the facts and stop validating and enabling industry influence in the science- and policy-making processes.
Madeline is the Institutional Outreach and Support Manager at Balanced. She holds a B.S. and M.S. in Nutrition from the Univ. of Texas and Tufts, respectively. As a nutrition expert, she advocates for more plant-based dining options in critical institutions with the aim of building healthier food environments and fostering better public health outcomes. You can reach her here: firstname.lastname@example.org
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