By Andrew Van Dam

You already know we’re getting heavier. Rising obesity rates are as American as apple pie — a cliché that seems freshly relevant in this context. But did you know we’re also getting shorter?

We didn’t! At least, not until we tried to use the National Health Interview Survey from the Centers for Disease Control and Prevention to figure out which professions boast the tallest workers.

We split the rankings by gender, so our analysis didn’t simply lead us to the most male-dominated jobs, such as mechanics and engineers. Among women, the tallest are public officials — a category that includes top executives as well as legislators — and a broad category that includes writers, artists, entertainers and athletes. Among men, the tallest are, again, public officials, who share that distinction with sales representatives.

This made us wonder: Heights are self-reported in this survey, and the tallest professions are known for their spin skills. So, could the great American height slump somehow be fueled by Americans growing more honest about their stature?

Well, no. We saw similar results in the National Health and Nutrition Examination Survey, a separate, gold-standard CDC data set that deputizes trained personnel to measure people’s height, weight and other dimensions according to a 91-page-manual. If anything, that source shows an even sharper decline in America’s height — though we’re still talking about fractions of an inch. Height shifts slowly, especially at the national level.

Similarly, a truly immense analysis of expert measurements in 200 countries and territories found that height had slipped among 19-year-old Americans in the late 1990s and 2000s. Nineteen-year-old American men were the 36th-tallest globally in 1985, but by 2019, they were 47th. Women the same age fell from 38th to 58th, behind China and Lebanon.

Also, we’re not as bad at guessing our measurements as you might think. In a 2020 analysis, American Cancer Society researchers asked more than 2,600 Americans to state their height and weight, and then — without warning — weighed and measured them. Their findings show that a large majority of us know our height within two inches, and our weight within 10-plus pounds. (Though we all tend to err on the svelte side.)

If anything, self-reported heights underestimate our national shortening, according to a separate U.S. comparison of self-reported and expert-measured heights. “Data showed that overreporting of height increased over time in both men and women,” the report’s authors write, “while underreporting of weight increased in men but not women.”

And there may be a perfectly reasonable explanation why public officials and sales representatives are so tall: bias. We prefer towering politicians — we last picked a president of below-average height for his era, William McKinley, in 1896 — and studies of people such as hiring managers often find that they believe a taller salesman, for example, will impress customers.

The most diminutive occupations hold another clue. The shortest men work on farms, while the shortest women clean. Both professions hire the highest share of immigrant workers for their respective genders. And Americans who were born outside the country tend to be much shorter than folks who were born here — it’s one of the biggest height gaps we saw.

The immigrant share of the U.S. workforce has almost doubled since 1994, from 11 percent to 20 percent, according to our analysis of Bureau of Labor Statistics data. Could immigration explain American shrinkage?

It’s certainly a major factor. But it’s not the only one. Even among native-born Americans, heights have slipped. That inspired us to look at the other subtle-but-seismic shift in the American workforce: aging.

As we hit our 50s, both men and women start getting shorter. And the share of American workers 55 or older has nigh on doubled since 1994, from 12 percent to 23 percent. But again, young, native-born workers also show a drop in height — although it falls short of the drop among the entire population.

At a loss, we called in the big guns. Longtime University of Munich economics professor John Komlos helped pioneer the study of height as a socioeconomic indicator as a student at the University of Chicago under Robert Fogel, eventual winner of the Nobel Prize in economics.

The Hungary-born, Midwest-raised Komlos spent much of his adult life buried deep in the archives, assembling centuries of human-height data using everything from colonial-era newspaper reports of the physical stature of runaway indentured servants and enslaved people to Austro-Hungarian military records.

We dragged Komlos out of a happy retirement in central North Carolina and asked him what the unholy heck was going on.

First, he assured us our data weren’t playing tricks. We’re shrinking. Vertically, at least. As a people, Americans were the tallest in the world by the 1800s, propelled by abundant land and cheap food. But today, access to modern medicine does more to determine height than do natural resources.

To pinpoint when everything changed, Komlos suggested that we focus on charting native-born people in prime ages (20 to 49) by birth year. Genetics play a supporting role, but the world you were born into really determines your height.

Following this method, the turning point becomes immediately and painfully clear: Around 1980, even native-born White men and women started getting shorter. (We’re looking specifically at Whites because they have the most robust data.)

And what term do we use for people born after 1980? Millennials! Incredibly, that generation is ground zero for American’s shrinking problem. Here at the Department of Data, we’ve developed an expertise in the ways millennials stand out in U.S. data, and it nonetheless took a world-famous authority to help us notice this one!

What changed in 1980? Childhood obesity began its steady rise, according to the National Center for Health Statistics. And Komlos believes America’s weight problem may be causing its height problem.

Evidence is mixed, but doctors analyzing almost 130,000 kids in California recently found that “childhood obesity is associated with earlier puberty in both boys and girls,” and Komlos and others have found that those children then experience a smaller growth spurt than their peers.

Louise Greenspan, a Kaiser Permanente San Francisco Medical Center pediatric endocrinologist who co-wrote “The New Puberty,” explained that obesity can cause early puberty because fat tissue pushes up estrogen levels for both girls and boys.

“Higher estrogen levels can lead to more mature bones. So your bones grow taller, faster, but then their growth plates fuse earlier,” Greenspan said. And if kids’ bones stop growing sooner, it’s possible they end up shorter. Greenspan said this is particularly true of young girls, which could help explain why we see heights dropping faster among millennial women.

But obesity might take a back seat to nutrition in making us shorter, Greenspan said. Changes in school lunches — “Now if kids are lucky enough to get a lunch at school, it is processed stuff that will last a full year if it stays on the shelf” — and larger societal factors shifted under infant millennials’ feet. After all, Komlos reminds us, the millennial generation wasn’t the only thing that began in 1981.

“The beginning of the Reagan administration is a watershed moment in the economic history of the U.S.,” he told us, pointing to his book, “Foundations of Real-World Economics.” “It was the end of the New Deal philosophy and a turn toward the idea that the market can deliver a good life.”

By driving down inequality, the New Deal and the Great Society literally lifted up the most vulnerable (and often shortest) Americans.

When all-star economists Hilary Hoynes, Diane Whitmore Schanzenbach and Douglas Almond (University of California at Berkeley, Northwestern University and Columbia University, respectively) ran the numbers on the rollout of food stamps in the United States from 1961 to 1975, they found that newfound access to food assistance in utero or early childhood caused a significant drop in stunting, or the odds of someone falling into the bottom 5 percent of heights as an adult.

With the Reagan-era pivot to market-based solutions, health-care costs soared. In the space of a decade, the United States went from spending 1.7 times as much as a typical advanced nation on health care to spending 2.1 times as much — a level near which it remains to this day.

As America’s health-care costs were rising, millennials were in their crucial early growth stages. Not coincidentally, Komlos has found that this is also when U.S. life expectancies began to falter.

“The U.S. fell behind European countries because Europe adopted a welfare state approach, which meant cheap medicine for the individual,” he said. The cheaper care and public support in Europe means “even poor people can afford to take their children to the doctor when they need to.”

But Komlos says there’s an even deeper issue than health care: rising inequality. Exact estimates vary, but sources tend to agree that 1970s were one of the most equitable eras in American history. Then, around 1981, inequality began to rise.

What does inequality have to do with height? Komlos explains that we lose more height to poverty that we gain from extreme wealth. If you make $200,000 a year, an extra $1,000 won’t make much difference in your household budget. But if you make $15,000 a year, losing $1,000 will take a substantial bite out of how well you can care for your kids. So, increasing inequality will push our average height ever lower even if average incomes and economic growth remain steady.

We see this result when, at Komlos’s suggestion, we split our height chart by education level.

People with a bachelor’s degree or higher have lost little, if any, height. The loss among those who never attended college has been much sharper, especially among women. (Again, this is for Whites, the group for which we have the best data.)

We’re guessing education doesn’t prevent shrinking. Instead, Komlos urges us to think about height the way we think about inheritance, as a visible sign of deeper advantages. If you’re given the resources you need to reach your full potential height, you’re also getting the resources you need to succeed in school and beyond.

For the rest of their lives, shorter millennials will bear the physical stamp of the inequality that erupted in their infancy. When we’re trying to explain America’s unluckiest generation, we should consider not just what they’ve become, but how they started out.