Category: Academic Reportage

Source: The Conversation – USA – By Jeff Moersch, Professor of Earth, Environmental, and Planetary Sciences, University of Tennessee

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

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What is below Earth, since space is present in every direction? – Purvi, age 17, India

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If you’ve seen illustrations or models of the solar system, maybe you noticed that all the planets orbit the Sun in more or less the same plane, traveling in the same direction.

But what is above and below that plane? And why are the planets’ orbits aligned like this, in a flat pancake, rather than each one traveling in a completely different plane?

I’m a planetary scientist who works with robotic spacecraft, such as rovers and orbiters. When my colleagues and I send them out to explore our solar system, it’s important for us to understand the 3D map of our space neighborhood.

Which way is ‘down’?

Earth’s gravity has a lot to do with what people think is up and what is down. Things fall down toward the ground, but that direction depends on where you are.

Imagine you’re standing somewhere in North America and point downward. If you extend a line from your fingertip all the way through the Earth, that line would point in the direction of “up” to someone on a boat in the southern Indian Ocean.

In the bigger picture, “down” could be defined as being below the plane of the solar system, which is known as the ecliptic. By convention, we say that above the plane is where the planets are seen to orbit counterclockwise around the Sun, and from below they are seen to orbit clockwise.

Even more flavors of ‘down’

Is there anything special about the direction of down relative to the ecliptic? To answer that, we need to zoom out even farther. Our solar system is centered on the Sun, which is just one of about 100 billion stars in our galaxy, the Milky Way.

Each of these stars, and their associated planets, are all orbiting around the center of the Milky Way, just like the planets orbit their stars, but on a much longer time scale. And just as the planets in our solar system are not in random orbits, stars in the Milky Way orbit the center of the galaxy close to a plane, which is called the galactic plane.

This plane is not oriented the same way as our solar system’s ecliptic. In fact, the angle between the two planes is about 60 degrees.

Going another step back, the Milky Way is part of a cluster of galaxies known the the Local Group, and – you can see where this is going – these galaxies mostly fall within another plane, called the supergalactic plane. The supergalactic plane is almost perpendicular to the galactic plane, with an angle between the two planes of about 84.5 degrees.

How these bodies end up traveling paths that are close to the same plane has to do with how they formed in the first place.

Collapse of the solar nebula

The material that would ultimately compose the Sun and the planets of the solar system started out as a diffuse and very extensive cloud of gas and dust called the solar nebula. Every particle within the solar nebula had a tiny amount of mass. Because any mass exerts gravitational force, these particles were attracted to each other, though only very weakly.

The particles in the solar nebula started out moving very slowly. But over a long time, the mutual attraction these particles felt thanks to gravity caused the cloud to start to draw inward on itself, shrinking.

There would have also been some very slight overall rotation to the solar nebula, maybe thanks to the gravitational tug of a passing star. As the cloud collapsed, this rotation would have increased in speed, just like a spinning figure skater spins faster and faster as they draw their arms in toward their body.

As the cloud continued shrinking, the individual particles grew closer to each other and had more and more interactions affecting their motion, both because of gravity and collisions between them. These interactions caused individual particles in orbits that were tilted far from the direction of the overall rotation of the cloud to reorient their orbits.

For example, if a particle coming down through the orbital plane slammed into a particle coming up through that plane, the interaction would tend to cancel out that vertical motion and reorient their orbits into the plane.

Eventually, what was once an amorphous cloud of particles collapsed into a disc shape. Then particles in similar orbits started clumping together, eventually forming the Sun and all the planets that orbit it today.

On much bigger scales, similar sorts of interactions are probably what ended up confining most of the stars that make up the Milky Way into the galactic plane, and most of the galaxies that make up the Local Group into the supergalactic plane.

The orientations of the ecliptic, galactic and supergalactic planes all go back to the initial random rotation direction of the clouds they formed from.

So what’s below the Earth?

So there’s not really anything special about the direction we define as “down” relative to the Earth, other than the fact that there’s not much orbiting the Sun in that direction.

If you go far enough in that direction, you’ll eventually find other stars with their own planetary systems orbiting in completely different orientations. And if you go even farther, you might encounter other galaxies with their own planes of rotation.

This question highlights one of my favorite aspects of astronomy: It puts everything in perspective. If you asked a hundred people on your street, “Which way is down?” every one of them would point in the same direction. But imagine you asked that question of people all over the Earth, or of intelligent life forms in other planetary systems or even other galaxies. They’d all point in different directions.

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Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

Jeff Moersch receives funding from NASA an the U.S. National Science Foundation.

– ref. What is below Earth, since space is present in every direction? – https://theconversation.com/what-is-below-earth-since-space-is-present-in-every-direction-245348

Source: The Conversation – USA – By Kathy Kiely, Professor and Lee Hills Chair of Free Press Studies, University of Missouri-Columbia

In December 2025, President Donald Trump filed a US$10 billion lawsuit against the BBC in a federal court in Florida. It was only the latest in a long series of high-dollar legal challenges Trump has brought against prominent media organizations, including ABC, CBS, The New York Times and The Wall Street Journal, among others.

Trump has won some sizable settlements in cases legal scholars had dismissed as largely lacking in merit. But as media scholars, we believe prevailing in court is not necessarily his primary goal. Instead, Trump appears to use lawsuits as a strategic weapon designed to silence his enemies and critics – who sometimes seem to be one and the same in his eyes.

Trump has always been litigious. Over the course of his life, he has been involved in more than 4,000 lawsuits. Many of these involved Trump suing for defamation over perceived threats to his reputation. Relatively few, however, have been successful, if success is defined as prevailing in courts of law.

But using litigation as a tool for intimidation can produce other results that can count as victory. We are concerned that the president may be using the courts as a tool not to correct the record but to muzzle potential watchdogs and deprive the public of the facts they need to hold him accountable.

Winning major settlements

Trump claims the BBC attempted to interfere with the 2024 election by misrepresenting statements he’d made. As with Trump’s other defamation suits, the odds appear long against the president winning his case against the British broadcaster in court.

Just after Trump’s election in 2024, ABC, whose parent company is Disney, promised to make a $15 million contribution to the Trump presidential library to settle a defamation suit many experts said had dubious merit.

CBS and its parent company Paramount Global settled an arguably weaker defamation suit involving editing of a “60 Minutes” interview with Kamala Harris that Trump said was done “to make her look better.” Paramount contributed $16 million to Trump’s presidential library and his legal fees in order, the company said, to avoid the “uncertainty and distraction” of litigation. That same month, the Federal Communications Commission approved the $8 billion acquisition of Paramount by Skydance Media.

Those two defamation suits were filed while Trump was still a presidential candidate. Weeks after winning reelection, Trump sued The Des Moines Register for publishing a preelection poll that suggested he might lose the swing state of Iowa. Instead, he carried the state by 13 percentage points.

Trump could have just gloated over his victory, as President Harry Truman did when he famously posed holding the Chicago Tribune’s “Dewey Beats Truman” headline the day after his reelection. Instead, Trump went to court, accusing The Des Moines Register and its pollster, J. Ann Selzer, of violating Iowa’s consumer protection laws by fraudulently deceiving consumers and campaign donors.

Even if Trump loses this suit, he has inflicted expensive litigation costs on a news organization.

The considerable costs of defense

From the 1960s until the late 1990s, leading media outlets, rich from advertising dollars, could afford to hire lawyers to defend against governmental overreach and protect their role in the U.S.’s democratic order. Those fights led to Supreme Court decisions shielding media outlets from most libel complaints and government censorship prior to publication.

But the rise of the internet and then social media led to the collapse of the economic model supporting traditional news production. As audiences and advertisers have fled traditional media outlets, including newspapers and broadcasters, the money to hire lawyers to defend against expensive defamation suits or fight for access to government information is much harder to find.

If even media giants such as ABC and CBS are settling rather than fighting, what local news editor is going to assign a story that might trigger a presidential lawsuit? That’s why Trump’s suit against The Des Moines Register is such an ominous development.

Giving up without a fight

What’s disheartening about the media giants’ capitulation is that they are at risk of squandering the protections afforded by the Constitution and the courts.

In medieval England, criticizing the king or peers of the realm was a crime. But early in U.S. history, attempts to enforce seditious libel laws by the British government and later by President John Adams and the Federalist-controlled Congress generated public outcry and rebuke. This was based in part on the understanding that in a democracy the people must be free to criticize those who govern them, a principle enshrined in the First Amendment.

The Supreme Court ratified this understanding of press freedom in its 1964 decision New York Times v. Sullivan. In a resounding victory for free expression, the justices held that government officials cannot prevail in defamation cases unless there is clear and convincing proof that their critics knowingly or recklessly disregarded the truth. Careless errors are not enough.

Under these protections, even Trump’s case against the BBC – where the network has admitted an ethical lapse – is not a certain winner, especially since the contested content didn’t air in Florida, where the lawsuit was filed.

Although Trump claims the BBC’s misleading edits implied that he directly incited protesters to storm the Capitol on Jan. 6, 2021, the network can argue in court that the inaccuracy is only technical, given that Trump truly did give a firebrand speech that was widely criticized as at least indirectly leading to the violence that followed . If the edited version of Trump’s speech is not appreciably more harmful to Trump’s reputation than his actual speech, Trump’s defamation claim would likely fail.

Trump is the first U.S. president to use the weight of his office to extract private settlements from news outlets tasked with holding him accountable. Ostensibly, these suits are to recover monetary damages for harm to his reputation, but they are part of a broader attack on what Trump perceives as hostile media coverage.

New limits from states

Some of Trump’s targets are fighting back.

One is the Pulitzer Prize Board, the defendant in yet another Trump defamation suit – in this case, over the awards the board gave for reporting on Russian interference in the 2016 presidential election.

In December 2025, the Pulitzer Prize Board asked the judge in the case to force the president to hand over tax and medical records to prove that he had suffered the financial and emotional harm he is claiming.

Another key development: Most states have enacted anti-SLAPP laws. SLAPP stands for “strategic lawsuits against public participation,” referring to cases filed to intimidate and discourage public criticism. Thirty-eight states, plus the District of Columbia, now have anti-SLAPP laws in place. It’s probably not a coincidence that Trump filed the latest iteration of his suit against The Des Moines Register on June 30, which happened to be one day before Iowa’s anti-SLAPP law took effect.

These state laws allow targets of SLAPPs to get early resolutions of meritless suits and can force people found to have filed such suits to pick up their targets’ legal bills.

Without such tools protecting First Amendment rights – and media organizations taking steps themselves to defend such rights – dissent might be characterized as a “deceptive trade practice,” and speech is no longer truly free.

Lyrissa Barnett Lidsky is affiliated with the Florida First Amendment Foundation.

Kathy Kiely does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Trump lawsuits seek to muzzle media, posing serious threat to free press – https://theconversation.com/trump-lawsuits-seek-to-muzzle-media-posing-serious-threat-to-free-press-272850

Source: The Conversation – USA (2) – By Skip York, Nonresident Fellow in Energy and Global Oil, Baker Institute for Public Policy, Rice University

U.S. President Donald Trump has ignited a contentious debate over who has the right to control Venezuela’s vast oil reserves.

Speaking on Jan. 3, 2026, after the U.S. military seized Venezuelan President Nicolás Maduro, the U.S. president declared, “We built Venezuela’s oil industry, and now we’re going to take it back.”

By Jan. 6, Trump was saying that Venezuela would provide the U.S. with up to 50 million barrels of oil in the near future.

The next day, the U.S. seized two tankers bound from Venezuela for other markets – less than a month after it seized two others it said were transporting Venezuelan oil.

Long-term plans go much further. Trump envisions major U.S. oil companies, such as Chevron and ExxonMobil, to invest some US$100 billion into reviving Venezuela’s struggling industry, with the investing companies reimbursed through future production. So far, neither Venezuelan authorities nor U.S. oil companies have said whether they’re willing to do this.

As a scholar of global energy, I believe that Trump’s words and actions, including his consultations with oil executives before Maduro’s removal, signal a bold push to reassert American dominance in a country with vast oil reserves.

Trump’s rationale

Trump’s “Venezuela took our oil, we’re taking it back” rationale apparently references the South American nation’s initial nationalization of its oil industry in 1976, plus a wave of expropriations in 2007 under Venezuelan President Hugo Chávez.

U.S. oil companies played a big role in launching and sustaining Venezuela’s oil boom, starting in the 1910s. Companies such as Standard Oil, a predecessor of ExxonMobil, and Gulf Oil, which eventually became part of Chevron, invested heavily in exploration, drilling and infrastructure, transforming Venezuela into a major global supplier.

Contracts from that era often blurred lines between reserve ownership and production rights. Venezuela legally retained subsoil ownership but granted or sold broad concessions to foreign operators, such as Royal Dutch-Shell. That effectively gave control of reserves and production to the oil companies, but not forever.

This ambiguity likely has played a role in Trump alleging outright theft through nationalization, a claim that holds little grounding in the historical precedent of how Venezuela and other nations have managed ownership of their natural reserves.

Oil nationalization

When a country nationalizes its oil industry, control is transferred from private, often foreign-owned, companies to the government.

Nationalization can involve the outright expropriation of facilities and reserves – with or without compensation – or the renegotiation of oil production contracts. Alternatively, a government may get a bigger stake in the joint ventures it already has with foreign oil companies.

While privately owned oil companies primarily are accountable to their shareholders and focus mainly on maximizing profits, most government-run oil companies have other priorities too. These might include pumping revenue into safety net programs, domestic energy security, the development of other industries and military spending.

Sometimes those other goals take so much money out of the oil company’s orbit that they interfere with operational efficiency and reinvestment, slowing growth or even reducing production capacity. That’s what happened in Venezuela, where oil production has fallen sharply since 2002.

But other Latin American countries have also nationalized their oil industries with better results.

Mexico’s experience

In Mexico, President Lázaro Cárdenas’ 1938 expropriation of foreign oil assets – primarily from U.S. and British companies – was the region’s first such assertion of economic independence.

Amid labor disputes and perceived exploitation, 17 privately owned companies were nationalized, creating Petróleos Mexicanos as Mexico’s government-run oil monopoly. Mexicans celebrate the formation of this company, known as Pemex, every year on March 18 as a symbol of national sovereignty.

Despite initial boycotts and diplomatic strain, Mexico eventually compensated the foreign companies that lost their property. But it isolated its oil sector from international capital and technology for decades.

Due to the depletion of Pemex’s largest oilfields, chronic underinvestment, a failure to adopt new technologies and unwise policy choices, production, which peaked at 3.8 million barrels a day in 2004, began to decline. Mexico responded in 2013 and 2014 with reforms that opened the oil, gas and power generation industries to private capital.

By 2018, political backlash around a perceived loss of sovereignty and uneven benefits led to a policy reversal. Oil output continues to shrink; it now stands at 1.8 million barrels per day.

Mexico’s experience underscores how oil nationalization can foster self-reliance while hindering production.

Brazil’s approach

Brazil also nationalized its oil industry in 1953, when President Getúlio Vargas established Petróleo Brasileiro S.A. as a state-owned company.

From the start, Petrobras had a monopoly over all Brazilian oil exploration and production. The government expanded the company’s scope when it nationalized all privately owned refineries by 1964.

Brazil’s oil nationalization was part of the country’s broader effort to develop its own industrial capacity and reduce its dependence on foreign oil.

Petrobras has changed significantly since its founding, especially after President Fernando Henrique Cardoso signed an oil deregulation law in 1997. It’s now a state-controlled company, in which investors may buy and sell shares. The government has forged many partnerships with private oil companies, drawing foreign investment.

This strategy succeeded. Production has quadrupled from 0.8 million barrels per day in 1997 to 3.4 million in 2024.

Shell, Total Energies, Equinor, ExxonMobil and other foreign oil companies have provided capital, technology and execution capacity, particularly with deep-water drilling.

Venezuela’s nationalization

Venezuela’s oil nationalization, by contrast, shifted from cooperation with foreign oil companies to confrontation with them.

President Carlos Andrés Pérez first nationalized Venezuela’s oil industry in 1976, creating Petróleos de Venezuela, S.A. Foreign companies received compensation of about 25% for losing their assets. Many transitioned into service providers or formed joint ventures with the new company, PDVSA.

Venezuela made its oil sector more open to foreign capital in the 1990s. It aimed at the time to boost output and develop the Orinoco Belt in eastern Venezuela, which has some of the world’s biggest oil reserves.

This policy contributed to Venezuelan production reaching a historical peak of more than 3 million barrels per day in 2002.

Chávez changes everything

Hugo Chávez, elected president of Venezuela in 1998, reversed course.

In 2003, after a strike briefly but severely slashed national output, Chávez consolidated control over the oil industry. He purged PDVSA of his critics, replacing managers who had expertise with his political allies, and fired over 18,000 employees.

Venezuela expropriated operating assets, converted contracts held by private companies into PDVSA-controlled joint ventures and made sharp and unpredictable increases in the taxes and royalties foreign oil companies had to pay.

Foreign oil companies suffered from chronic payment delays, along with restrictive foreign exchange rules and new laws that weakened contract enforcement and made it harder for companies to use arbitration to resolve disputes.

In 2007, Chávez forced foreign oil companies partnering with PDVSA to renegotiate their agreements, leading to the partial nationalization of their stakes in those ventures.

Several foreign oil companies, including ConocoPhillips and ExxonMobil, rejected the new terms of engagement and left Venezuela.

Their legal disputes with Venezuela over billions of dollars in joint venture assets and severed revenue-sharing agreements have never been resolved.

Chevron, however, stayed put.

The Houston-headquartered company, which has had a presence in Venezuela since 1924, now plays the largest role of any foreign oil company in the country. It produces 240,000 barrels per day, about 25% of Venezuela’s total output.

The government also reclassified vast oil deposits as “proven” at a time when global oil prices were very high, rendering their exploration and production more economically viable. That change tripled this self-reported and never-verified estimate of Venezuela’s proven oil reserves to approximately 300 billion barrels.

Conditions get worse under Maduro

Venezuelan oil output further declined while Maduro served as president, falling to 665,000 barrels per day in 2021. Since then, production has recovered somewhat, rebounding to about 1.1 million barrels per day by late 2025 – about one-third of its historic high.

This overall decline is due to mismanagement, corruption and more than a decade of U.S. sanctions. Infrastructure decay – leaking pipelines, outdated refineries held together by makeshift repairs – has exacerbated this crisis.

Many hurdles are in the way of the industry’s recovery, including ongoing and potentially future legal disputes, geopolitical risks and the need for massive investments. Returning Venezuela’s oil production to its peak of 3 million barrels per day could cost more than $180 billion.

Better example

As Brazil’s experience suggests, governmental control over oil production and sales is not inherently bad for a country’s economic welfare.

Norway is an even stronger example. That oil-rich Nordic country has evaded what some scholars call the “resource curse” by treating the oil that its nationally owned company, now called Equinor, has produced as a source of lasting wealth for the Norwegian people.

Revenue from the Norwegian government’s 67% stake in Equinor has accumulated in a sovereign wealth fund worth more than $2 trillion and helped Norway diversify its economy.

As the Venezuelan government regroups following Maduro’s removal, there’s much it can learn from other countries that have managed to maintain more stability alongside state-controlled oil production.

Did prior consulting work for PdVSA in 2002-2003

– ref. Venezuela’s oil industry has flailed under government control – Mexico and Brazil have had more success with nationalizing – https://theconversation.com/venezuelas-oil-industry-has-flailed-under-government-control-mexico-and-brazil-have-had-more-success-with-nationalizing-272785

Source: The Conversation – USA (2) – By Caroline Levander, Vice President Global Strategy & Carlson Professor in the Humanities, Rice University

A college degree was once seen as the golden ticket to landing a well-paying job. But many people are increasingly questioning the value of a four-year degree amid the rising cost of college.

Almost two-thirds of registered voters said in an October 2025 NBC News poll that a four-year college degree isn’t worth the cost – marking an increase from 40% of registered voters who said that college wasn’t worth the cost in June 2013.

Caroline Field Levander, the vice president for global strategy and an English professor at Rice University, argues in her December 2025 book “Invent Ed” that people have lost sight of two factors that made universities great to begin with: invention and creativity.

Amy Lieberman, education editor at The Conversation U.S., spoke with Levander to break down the benefits of going to college and university – and how schools can better demonstrate their enduring value.

How can we measure the value of a college degree?

College graduates earn substantially more than people who do not have a college degree.

The average high school graduate over a 40-year career earns US$1.6 million, according to 2021 findings by the Georgetown University Center on Education and Workforce. The average college graduate, over this same 40-year time frame, earns $2.8 million. That $1.2 million difference amounts to around $30,000 more salary per year.

People who earn a degree more advanced than a bachelor’s, on average, earn $4 million over 30 years, making the lifetime earning difference $2.4 million between these graduates and people with just a high school diploma.

College graduates are also better protected against job loss, and they weather job disruption cycles better than high school graduates.

The unemployment rate for people with a high school degree was 4.2% in 2024, according to the U.S. Bureau of Labor Statistics. By contrast, 2.5% of people with a bachelor’s degree and 2.2% of people with a master’s degree were unemployed in 2024.

Do any of these benefits extend beyond individual students?

In addition to the substantial financial benefits college graduates experience, colleges and universities are major employers in their communities – and not just professors and administrators. Higher education institutions employ every trade and kind of worker, from construction workers to police, to name a few.

Universities are crucial to developing and strengthening the U.S. economy in other ways. The discoveries that faculty and researchers make in laboratories lead to new products, businesses and ideas that drive the U.S. economy and support the country’s financial health.

Researchers at the University of Texas Southwestern did important work in helping to discover statins, while scientists at the University of Pennsylvania developed the mRNA vaccine. The list of inventions that started at universities goes on and on.

Some people are questioning the value of a degree. What role can universities play in reassuring them of their relevance?

Discovery and invention have traditionally been the focus of many graduate programs and faculty research, while undergraduate college educations tend to focus on ensuring that students are able to successfully enter the workforce after graduation.

Undergraduate students need to gain competency in a field in order to contribute to society and advance knowledge.

But I believe universities need to teach something else that is equally valuable: They also need to build creative capacity and an inventive mindset into undergraduate education, as a fundamental return on the investment in education.

Employers report that creativity is the top job skill needed today. The IBM Institute for Business Value, for example, concluded in 2023 that creativity is the must-have skill for employee success in the era of generative AI.

The Harvard Business Review reports that employers are developing short courses aimed to build creative capability in their workers.

What can faculty and students easily do to encourage creativity and innovation?

Professors can build what I call a “growth mindset” in the classroom by focusing on success over time, rather than the quick correct answer. Faculty members can ask themselves as they go into every class, “Am I encouraging a growth mindset or a fixed mindset in these students?” And they can use that answer to guide how they are teaching.

Students could also consider committing to trying new courses in areas where they haven’t already been successful. They could approach their college experience with the idea that grades aren’t the only marker of success. And I think they could benefit from developing thoughtful ways to describe their journey to future employers. Simple practices like keeping a creativity notebook where they record the newest ideas they have, among many others that I describe in my new book, will help.

And university leaders need to open the aperture of how we define our own success and our university’s success so that it includes creative capability building as part of the undergraduate curriculum.

Caroline Levander does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Financial case for college remains strong, but universities need to add creative thinking to their curriculum – https://theconversation.com/financial-case-for-college-remains-strong-but-universities-need-to-add-creative-thinking-to-their-curriculum-269463

Source: The Conversation – USA (3) – By Moul Dey, Professor of Nutrition Science, South Dakota State University

Older adults can dramatically reduce the amount of ultraprocessed foods they eat while keeping a familiar, balanced diet – and this shift leads to improvements across several key markers related to how the body regulates appetite and metabolism. That’s the main finding of a new study my colleagues and I published in the journal Clinical Nutrition.

Ultraprocessed foods are made using industrial techniques and ingredients that aren’t typically used in home cooking. They often contain additives such as emulsifiers, flavorings, colors and preservatives. Common examples include packaged snacks, ready-to-eat meals and some processed meats. Studies have linked diets high in ultraprocessed foods to poorer health outcomes.

My team and I enrolled Americans ages 65 and older in our study, many of whom were overweight or had metabolic risk factors such as insulin resistance or high cholesterol. Participants followed two diets low in ultraprocessed foods for eight weeks each. One included lean red meat (pork); the other was vegetarian with milk and eggs. For two weeks in between, participants returned to their usual diets.

A total of 43 people began the dietary intervention, and 36 completed the full study.

In both diets, ultraprocessed foods made up less than 15% of the total calories – a significant reduction from the typical American diet, where more than 50% of total calories comes from ultraprocessed foods. The diets were designed to be realistic for everyday eating, and participants were not instructed to restrict calories, lose weight or change their physical activity.

We prepared, portioned and provided all meals and snacks for the study. Both diets emphasized minimally processed ingredients and aligned with the 2020-2025 Dietary Guidelines for Americans, the U.S. government’s nutrient-based recommendations for healthy eating, while providing similar calories and amounts of key nutrients.

The 2025-2030 Dietary Guidelines for Americans, released on Jan. 7, 2026, explicitly recommend eating less ultraprocessed food, but the previous versions of the guidelines did not specifically address food processing. Our feeding study design allowed us, for the first time, to examine the health effects of reducing ultraprocessed foods while keeping nutrient levels consistent with recommended targets.

We compared how participants fared while eating their habitual diets with how they responded to the two diets that were low in ultraprocessed foods. During the periods when participants ate fewer ultraprocessed foods, they naturally consumed fewer calories and lost weight, including total and abdominal body fat. Beyond weight loss, they also showed meaningful improvements in insulin sensitivity, healthier cholesterol levels, fewer signs of inflammation and favorable changes in hormones that help regulate appetite and metabolism.

These improvements were similar whether participants followed the meat-based or the vegetarian diet.

Why it matters

Ultraprocessed foods make up more than half the calories consumed by most U.S. adults. Although these foods are convenient and widely available, studies that track people’s diets over time increasingly link them with obesity and age-related chronic diseases such as Type 2 diabetes and heart disease. With older adults making up a growing share of the global population, strategies that preserve metabolic health could support healthy aging.

Most previous feeding studies testing how ultraprocessed foods affect people’s health haven’t reflected real-world eating, especially among Americans. For example, some studies have compared diets made up almost entirely of ultraprocessed foods with diets that contain little to none at all.

Our study aimed to more closely approximate people’s experience while still closely tracking the foods they consumed. It is the first to show that for older adults a realistic reduction in ultraprocessed foods, outside the lab, has measurable health benefits beyond just losing weight. For older adults especially, maintaining metabolic health helps preserve mobility, independence and quality of life.

What’s still unknown

Our study was small, reflecting the complexity of studies in which researchers tightly control what participants eat. It was not designed to show whether the metabolic improvements we observed can prevent or delay diseases such as diabetes or heart disease over time. Larger, longer studies will be needed to answer that.

On the practical side, it’s still unclear whether people can cut back on ultraprocessed foods in their daily lives without structured support, and what strategies would make it easier to do so. It’s also not fully understood which aspects of processing – for example, additives, emulsifiers or extrusion – matter more for health.

Answering these questions could help manufacturers produce foods that are healthier but still convenient – and make it easier for people to choose healthier food options.

The Research Brief is a short take on interesting academic work.

Moul Dey receives funding from the National Pork Board, the U.S. Department of Agriculture, and the National Institute of Food and Agriculture (Hatch project).

– ref. Eating less ultraprocessed food supports healthier aging, new research shows – https://theconversation.com/eating-less-ultraprocessed-food-supports-healthier-aging-new-research-shows-271986