The critical health and nutrition data we nearly lost this year
Chances are very good you have never taken the National Health and Nutrition Examination Survey, or NHANES: only 5,000 Americans are part of it each year. But 5,000 of us, randomized carefully to represent all Americans, is enough to provide public health and nutrition scientists and policy makers solid data to accurately check:
The growth of obesity, diabetes, high blood pressure, osteoporosis, and kidney, respiratory, infectious, and sexually transmitted diseases
Use of smoking, vaping, alcohol, and drugs
Physical activity, sexual, and other health-related behaviors
How we eat and drink and our nutritional health.
Mobile NHANES exam centers are deployed around the country for in-person examinations and measurements, blood and urine sample collecting, and diet and health interviews.
The data is used to:
Study the spread of disease and detect factors that may be linked to diseases
Provide a solid scientific basis for health and nutrition policies
Design health and nutrition programs and inform the practice of medicine and nutritional interventions.
Inform the U.S. Dietary Guidelines, due out this month.
Important NHANES revelations
NHANES had its origins in the early 1960s. Soon after adding nutrition to the survey and exams in 1971, NHANES found blood level deficiencies of iron in women, children, and older Americans, leading to federal requirements to fortify grain and cereal with iron.
Then, still in the 1970’s, NHANES revealed that Americans had too much of another heavy metal in their blood: lead, dangerous at any level. The federal government subsequently de-leaded our dangerous gas and paint, and a reduction from high blood lead levels in almost everyone in the 1970s to high levels in 4% of Americans was achieved within 20 years.
NHANES exams and interviews found that about 40% of Americans with high blood pressure don’t realize it.
Similarly, NHANES has shown that about one-quarter of adults with diabetes don’t know they have it.
And we nearly lost the ability to collect this data?
In October the Trump administration used the government shutdown as an opportunity to fire 1,300 CDC employees including 100 key NHANES team members. An uproar followed in the public health and nutrition worlds. By the end of November everyone was re-hired and paid back pay, but the lasting damage is hard to assess.
Ultraprocessed food and NHANES
An example of how NHANES data should be informing public policy is demonstrated by its use in recent research of ultraprocessed food consumption and associated health risks.
Ultraprocessed food creation and marketing took off in the 1950s and 1960s. I use 1953 as the start of what might be called “the era of the ultraprocessed.” 1953 was the year of the first McDonald’s franchise and the first Swanson frozen dinner.
It is good to remember that many brands of ultraprocessed products that are still popular started prior to World War II, including Coca-Cola (1886), Jell-O (1897), and Crisco (1911) – still a source of toxic trans fats, by the way, even though Crisco is allowed by the FDA to say “zero grams” of trans fats on its labels. In the 1910s we got Oreos, Nathan’s hot dogs, Aunt Jemima syrup, Hellmann’s mayonnaise, and Marshmallow Fluff. The Roaring Twenties brought us Wonder Bread, Velveeta, and Kool-Aid, followed by the Great Depression of the 1930s and Spam, Kraft Macaroni & Cheese, and Ritz Crackers.
These iconic brands represent whole categories of ultraprocessed foods like sugar- and artificially-sweetened beverages, packaged snacks, cookies, meat and meatless products and fish sticks, sauces and toppings, breakfast cereals, and, the bane of my diet, ice cream, all of which now fill the aisles of grocery stores that are supersized on a scale not envisioned prior to World War II.
Carlos Monteiro is the most prominent name in ultraprocessed food research, having coined the term “ultraprocessed” in 2009. Using NHANES data, a team of researchers, including Monteiro, found that between 2001 and 2018, ultraprocessed food consumption increased from 53.5% of the average American adult’s calories to 57%. That 3.5% increase over 17 years may represent a recent trend toward leveling off in the consumption of ultraprocessed food.
We don’t have good data for ultraprocessed food consumption in the 20th century, so we can’t put a number on how much was being consumed in the 1950s. But certainly it was a low number compared to the 53.5% of calories in 2001: on that there is consensus. So very rapid growth in the last 50 years of the century, was followed by what appears to be a tendency toward a flattened curve in ultraprocessed food consumption.
That trend toward leveling off is a good thing given the mounting evidence in over 100 studies of ultraprocessed food’s association with death and chronic disease, including obesity, diabetes, high blood pressure, heart disease, stroke, kidney disease, Crohn’s disease, and depression.
And the trend toward the leveling off of ultraprocessed food consumption, following its meteoric rise in the last half of the previous century, should not be surprising. Today, the average American already consumes almost 60% of their calories eating ultraprocessed food. I hope our taste buds and some human instinct to eat natural foods will end the growth in ultraprocessed food consumption.
The more ultraprocessed food we eat, the more that minimally processed foods like fresh fruits and vegetables and simply prepared meats, poultry, and fish will be displaced from our diets. The study of NHANES data from 2001 to 2018 found consumption of healthier, minimally processed food decreased 6%, from 1/3 to about ¼ of out calories, while unhealthy ultraprocessed food calories consumption increased 3.5% during those 17 years.
What is required for the recovery of America’s nutritional health and a subsequent substantial reduction in chronic disease are policies and programs that greatly reduce the consumption of ultraprocessed foods.
Kudos to San Francisco, which this week filed suit against ultraprocessed food makers including Coca-Cola, PepsiCo, Kraft Heinz, Mondelez, Nestlé, Mars, ConAgra, and cereal manufacturers Post, General Mills, and Kellogg. San Francisco is suing on the basis of the evidence that the ultraprocessed products marketed and sold to consumers create a burden of chronic disease.
The CDC’s fast food report
The CDC’s own, in-house analysis and reporting of the NHANES data has tremendous value to public health policy and programming in America.
In April the CDC’s National Center for Health Statistics reported good news, sort of. Two-thirds of Americans on a given day in 2022 or 2023 did not eat fast food. Of course, that means one-third of Americans did go to a McDonald’s, Starbucks, Chick-fil-A, to name the top three, or another purveyor of fast food. Unfortunately, 9%, almost one in ten, of survey respondents got more than half their calories in fast food that day.
The CDC’s study found that adults with obesity ate 40% more fast food calories compared to adults with underweight or normal weight status.
A related CDC study found that American youth are eating fast food at almost the same levels as adults, 30% of children and adolescents ages 2 to 20 have fast food on a given day, and 11% of their overall calories come from fast food, compared to 32% and 12% for adults. The good news here is that the CDC reports these rates decreased a little for both youths and adults from 2013 to 2023. We can only hope that this apparent trend continues.
To this end, our neighbors to the north and south, Canada and Mexico, along with nations in Europe, Asia, and South America, do a better job limiting fast food advertising and other unhealthy food marketing that targets children. Some ban it all together.
CDC’s obesity report
Obesity in America was reported by the CDC in 2024 using NHANES data from 2021 to 2023. The rate among adults was 40%, without a significant difference between men and women. However, there was a big difference in severe obesity with a rate of 6.7% in men and, approaching twice as much, 12.1%, in women.
The good news is that the level of obesity in adults was unchanged between 2013 and 2023, although the level of severe obesity grew considerably, from 7.7% to 9.7%, overall.
I gave thanks at Thanksgiving for public health professionals. That includes the thousands of talented people at the CDC dedicated to true science and the public health. I would like to exclude, of course, those current CDC political appointees I know about from any consideration.
NHANES is a key source of data and the work gathering it, reporting it, and making it available to other researchers around the world is essential to improving the well-being of Americans.
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