“What comes next is the first time this one-of-a-kind aircraft will fly supersonic,” said Cathy Bahm, project manager for NASA’s Low Boom Flight Demonstrator. “We are starting toward the mission conditions test point that X-59 was designed for.”

Following months of flight testing, the X-59 team reviewed its progress in late May and is now preparing for a new phase that will push the aircraft to greater altitudes and higher speeds. These flights are intended to show how the aircraft performs under the operating conditions required for NASA’s Quesst mission, which aims to collect data on quiet supersonic flight.

First Supersonic Flights Ahead

NASA expects the X-59 to exceed the speed of sound for the first time during test flights scheduled for early June. The aircraft is expected to fly at more than 630 mph at an altitude of about 43,000 feet, marking a major milestone in the program.

The aircraft will then attempt a “mission conditions” flight, reaching Mach 1.4 (925 mph) at approximately 55,000 feet. Those performance targets are important because they match the conditions NASA plans to use when flying the X-59 over U.S. communities. During those future flights, researchers will gather public feedback about the aircraft’s quieter sonic “thump” and evaluate how people respond to it.

Although the X-59 was designed to minimize the disruptive sonic boom typically associated with supersonic aircraft, these initial supersonic flights are not intended to demonstrate that capability. A conventional supersonic chase aircraft will accompany the X-59, and the louder sonic booms produced by the chase plane will mask any quieter sound generated by the experimental jet.

During supersonic testing this summer, the chase aircraft will also carry a specialized shock-sensing probe that will collect the first measurements of the X-59’s shock waves.

What NASA Learned From Earlier Flights

The aircraft’s first phase of testing successfully met a number of important objectives and produced valuable data for engineers.

After its maiden flight in October 2025, the X-59 underwent a planned maintenance period before returning to flight testing in March 2026. Since then, the aircraft has completed 14 additional flights and achieved several notable milestones, including:

• Completing its first gear swing, retracting its landing gear and revealing its distinctive aerodynamic profile in flight.
• Reaching altitudes of up to 43,000 feet and speeds approaching the sound barrier at Mach 0.95, roughly 627 mph.
• Conducting its first dual-flight day and later making multiple flights per day a routine part of testing.
• Transitioning from increasingly fast and high-altitude flights to slower, lower-altitude testing to evaluate performance across a wider range of operating conditions.

Information gathered during these flights has helped engineers evaluate key systems, including fuel delivery, hydraulics, environmental controls, and the aircraft’s eXternal Vision System. This unique camera-based system replaces a traditional forward-facing windshield by providing the pilot with a live display view ahead of the aircraft.

Teams also closely monitored how the X-59 performed during takeoffs, landings, and flight operations. Strain gauges installed throughout the aircraft measured structural loads and recorded how the airframe responded to various forces encountered during testing.

Expanding the Flight Envelope

The next set of flights will challenge the aircraft in a new way. Pilots will continue working through planned test points while engineers evaluate performance in true supersonic conditions.

“Flying at supersonic speeds is a major milestone for the X-59 team,” Bahm said. “Every step of envelope expansion brings us closer to demonstrating the quiet supersonic capability that is at the heart of the Quesst mission. Completing the first mission-conditions flight is especially meaningful — it’s the moment where we begin validating the aircraft in the environment it was designed for.”

Along with reaching mission conditions, the aircraft is expected to achieve its top planned performance targets during this testing phase, including a maximum speed of Mach 1.6 (1,218 mph) and a maximum altitude of 60,000 feet.

Even so, not every flight will take place at supersonic speed. Engineers will continue conducting a mix of subsonic and lower-altitude flights to monitor the aircraft’s behavior under a variety of conditions.

“These flights not only deepen our confidence in the X-59’s performance — they mark our progression toward the future phases of the mission that will ultimately help shape the future of supersonic travel,” Bahm said.

Preparing for Phase 2 of the Quesst Mission

All flights completed so far, along with the upcoming test campaign, are part of Phase 1 of NASA’s Quesst mission. This stage focuses on proving the aircraft’s performance and airworthiness.

Some flights will also involve the early use of specialized equipment, including a probe mounted on one of NASA’s F-15 research aircraft. The instrument is designed to measure the X-59’s unique shock wave signature.

The information collected during these early measurement flights will help engineers prepare for Quesst Phase 2, scheduled to begin later this year. During that stage, teams will directly measure the aircraft’s supersonic flight signature to confirm that it is producing the quiet supersonic thump it was designed to generate.

“Aviation pioneer Otto Lilienthal said, ‘To design a flying machine is nothing. To build one is something. But to fly is everything.’ The 15 X-59 flights we’ve accomplished since March have been everything to this team and the mission,” Bahm said. “Every flight has pushed the boundaries of what’s possible, steadily expanding the envelope and strengthening our confidence in the aircraft.”

However, Bahm emphasized that the team remains focused on the work ahead.

“As we look ahead to the upcoming flights, we’re poised to open the envelope even further — moving boldly toward the mission test point this aircraft was built to achieve,” Bahm said. “Flying supersonic and reaching these milestones isn’t just progress; it’s the realization of years of perseverance, innovation, and teamwork. Each step brings us closer to Phase 2, and to the future of commercial supersonic flight.”

What makes Roman especially exciting is where it will look. Most exoplanet discoveries to date have come from relatively nearby regions of the galaxy. Roman, however, will search largely unexplored areas of the Milky Way, offering a much broader view of planetary systems across our galaxy.

“Our galaxy is home to a variety of different environments, but when it comes to hunting for exoplanets, we’ve really only explored one: our own neighborhood,” said Elisa Quintana, an exoplanet researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Quintana leads a team focused on building software and simulations to help prepare for Roman’s exoplanet transit observations. “Roman will extend the search far enough to encompass other galactic habitats, which could help us learn how planet formation varies across different regions of the Milky Way.”

Today, most known exoplanets are located within a few thousand light years of Earth. One of Roman’s primary surveys will look far beyond that range, examining stars through the Milky Way’s densely packed central bulge and extending all the way to the far side of the galaxy.

Searching the Milky Way for New Worlds

Roman will continuously monitor stars across a large section of the Milky Way, looking for changes in their brightness.

One technique relies on planetary transits. When a planet passes in front of its star from our perspective, it blocks a small amount of starlight, causing the star to dim temporarily.

The telescope will also use a second technique called microlensing. In these events, the gravity of a foreground star and any accompanying planets magnifies the light of a more distant background star, briefly making it appear brighter.

Each method is sensitive to different kinds of planets.

The transit technique, which is expected to uncover roughly 100,000 worlds, is particularly effective at detecting large, extremely hot planets. These planets block more light from their stars and complete their orbits more frequently, making them easier to spot.

Microlensing, which is expected to reveal more than 1,000 worlds, excels at finding planets farther from their stars, including systems that resemble our own solar system. It can detect planets as small as Earth and Mars, both within habitable zones and at greater distances from their stars. Many of these worlds are extremely difficult, or even impossible, to find using other detection methods.

Together, these complementary approaches will allow scientists to investigate how planets form throughout the galaxy, including in the region where our own solar system may have originated.

Clues to Earth’s Origins

Today, our solar system lies about 27,000 light years from the center of the Milky Way. Researchers believe it likely formed roughly 10,000 light years closer to the galactic center before gradually moving outward to its current location.

Evidence for this idea comes largely from the Sun’s chemical composition.

Astronomers use the term heavy elements to describe all elements other than hydrogen and helium, which were produced shortly after the universe formed. Heavier elements are created inside stars and become more abundant over time as successive generations of stars live and die.

Stars located in the galaxy’s outer regions generally contain fewer heavy elements. By contrast, stars in the galactic bulge are older and tend to be richer in elements such as silicon, oxygen, and magnesium.

These chemical differences may influence the types of planets that form around stars. Some systems could produce larger planets, rockier worlds, or perhaps more planets overall. In some cases, stellar composition may even affect whether planets form at all.

Astronomers have already found evidence that such relationships exist among nearby stars.

“Stars with more heavy elements tend to host more planets, especially giant ones,” said Robby Wilson, a postdoctoral fellow at NASA Goddard, who led a study about Roman’s expected transiting planet yield.

By examining entirely different populations of stars and planets across the Milky Way, Roman could greatly expand these studies and help reveal how common planetary systems like our own really are.

“Roman will be especially powerful because it will observe hundreds of millions of distant stars, letting scientists compare faraway planet populations to those found nearby,” said Wilson. “All of that data will give us a lot to comb through, so we’re prepping by creating synthetic data, detecting simulated planets, and using machine learning to filter out false positives. That way we’ll be ready to go right away when real data comes pouring in.”

All data collected by Roman will be publicly available, allowing researchers and citizen scientists alike to participate in the search for new worlds.

Studying Alien Atmospheres and Weather

Roman could also provide atmospheric information for thousands of the transiting planets it discovers.

“Roman won’t analyze atmospheres in the same in-depth way as missions like NASA’s James Webb Space Telescope, but it will gather different information on a much larger scale,” Wilson said.

While the James Webb Space Telescope focuses on detailed chemical analyses of individual planets, Roman will examine broader temperature and climate patterns across thousands of worlds. This large statistical dataset could identify important trends and help guide future observations by Webb and other observatories.

One area of focus will be “hot Jupiters,” giant planets roughly the size of Jupiter that orbit extremely close to their stars. Since Jupiter is about 11 times wider than Earth, these worlds are enormous and often complete an orbit in just a few days. Their high temperatures allow them to emit detectable infrared radiation.

Roman’s infrared instruments will be able to observe these glowing planets and study how their brightness changes over time.

When a hot Jupiter passes in front of its star, astronomers see one dip in brightness. A second, smaller dip occurs when the planet moves behind the star and its light is temporarily blocked.

“That secondary dip tells us how bright, and therefore how hot, the planet is,” said Wilson. “By tracking how the planet’s brightness changes over its orbit, Roman can also see differences between the day side and night side, and even detect shifts in where the hottest region is on the planet. That tells us about atmospheric winds and heat circulation.”

A New Era for Exoplanet Discovery

NASA’s Kepler mission transformed exoplanet science by monitoring roughly 100,000 stars and demonstrating that planets are extraordinarily common throughout the Milky Way.

“NASA’s now-retired Kepler mission’s survey of 100,000 stars revolutionized the field of exoplanets over a decade ago, and taught us that planets are even more common than stars in our galaxy,” said Jorge Martínez-Palomera, an astronomer at NASA Goddard who is helping prepare for Roman’s exoplanet data.

Roman is expected to take that legacy much further. Its galactic bulge survey alone will observe approximately 100 million stars while exploring regions of the Milky Way that remain largely uncharted.

“Roman’s galactic bulge survey will observe around 100 million stars and probe underexplored areas of our galaxy, which will provide a foundational dataset that will likewise revolutionize what we know about other worlds and our place in the Universe.”

The findings were published in two papers in the same issue of Nature and challenge decades of assumptions about the thymus. The results indicate that the organ remains important throughout adulthood and could eventually help guide disease prevention strategies and cancer treatment decisions.

“The thymus has been overlooked for decades and may be a missing piece in explaining why people age differently, and why cancer treatments fail in some patients,” said Hugo Aerts, PhD, corresponding author on the papers and director of the Artificial Intelligence in Medicine (AIM) Program at Mass General Brigham. “Our findings suggest thymic health deserves much more attention and may open new avenues for understanding how to protect the immune system as we age.”

What the Thymus Does

Located in the chest, the thymus helps train T cells, a type of immune cell that helps defend the body against infections and disease. Because the organ gradually shrinks after puberty and produces fewer new T cells over time, many scientists assumed it played only a limited role in adult health.

As a result, the thymus has received relatively little attention in large population studies. Earlier research connected T cell diversity to aging and declining immune function, but those studies were typically small and focused on blood samples.

The new research took a much broader approach. Investigators analyzed data from more than 25,000 adults participating in a national lung cancer screening trial, along with more than 2,500 people enrolled in the Framingham Heart Study, a long-running study that tracks the health of generally healthy adults.

AI Reveals Links to Longevity and Disease Risk

Using artificial intelligence (AI) to evaluate routine CT scans, the researchers measured the size, structure, and composition of the thymus. From those measurements, they created a “thymic health” score.

People with higher thymic health scores experienced significantly better outcomes. Compared with individuals who had poorer thymic health, they had about a 50% lower risk of death from any cause, a 63% lower risk of death from cardiovascular disease, and a 36% lower risk of developing lung cancer. These relationships remained strong even after accounting for age and other health factors.

The researchers believe that declines in thymic health may reduce T cell diversity, making it harder for the immune system to recognize and respond to new threats such as cancer and other diseases.

Their analysis also identified several factors associated with poorer thymic health, including chronic inflammation, smoking, and higher body weight. These findings suggest that lifestyle factors and ongoing inflammation may affect the immune system’s ability to remain resilient over time.

Thymus Health and Cancer Immunotherapy

In a separate study, the team examined CT scans and clinical outcomes from more than 1,200 cancer patients treated with immunotherapy.

The results showed that patients with healthier thymuses tended to respond better to treatment. They faced about a 37% lower risk of cancer progression and a 44% lower risk of death, even after researchers adjusted for differences in patients, tumors, and treatment approaches.

According to the researchers, these findings highlight a potentially important but previously underrecognized role for the thymus in determining how effectively modern cancer immunotherapies work.

More Research Needed

The scientists emphasize that additional studies will be needed to confirm the results. They also note that the imaging technique used to measure thymic health is not yet ready for routine use in clinical practice.

Although lifestyle factors were associated with thymic health, the studies did not investigate whether changing those factors can directly improve thymus function.

The research team is continuing to explore other influences on thymic health. One ongoing study is examining whether unintended radiation exposure to the thymus during lung cancer treatment could affect patient outcomes.

“Improving our understanding and monitoring of thymic health could eventually help physicians better assess disease risk and guide treatment decisions,” said Aerts.

In addition to Aerts, study co-authors of the overall adult health paper include Simon Bernatz, Vasco Prudente, Suraj Pai, Asbjørn Kjær, Yumeng Cao, Jiachen Chen, Asya Lyass, PhD, Borek Foldyna, Leonard Nürnberg, Christopher Abbosh, Charles Swanton, Mariam Jamal-Hanjani, MD, PhD, Michael T. Lu, Joanne M. Murabito, Kathryn L. Lunetta, and Nicolai J Birkbak.

Aerts’ co-authors of the immunotherapy outcomes paper include Simon Bernatz, Vasco Prudente, Suraj Pai, Asbjørn Kjær, Alessandro Di Federico, Andrew Rowan, Selvaraju Veeriah, Lars Dyrskjøt, Leonard Nürnberg, Joao V. Alessi, Patrick A. Ott, Elad Sharon, Allan Hackshaw, Nicholas McGranahan, Christopher Abbosh, Raymond H. Mak, Danielle Bitterman, Mark Awad, Biagio Ricciuti, Charles Swanton, Mariam Jamal-Hanjani, and Nicolai J Birkbak, PhD.

This research received funding support from the National Institutes of Health, European Research Council, Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Lundbeck Foundation, Novo Nordisk Foundation, and Savvaerksejer Jeppe Juhl og Hustru Ovita Juhl Research Stipend.

In 2015, Sweden drew international attention when researchers reported that its Conservation Performance Payment (CPP) program, the oldest initiative of its kind, had helped boost populations of the endangered wolverine.

More than a decade later, however, that early success appears increasingly difficult to maintain. The program was designed to benefit both wolverines and the Indigenous Sámi reindeer herders who share the landscape with them. New findings suggest that the arrangement is under growing strain.

Researchers from the University of York and the Swedish Agricultural University found that documented wolverine numbers have dropped sharply in parts of northern Sweden where the species was once strongest. At the same time, government payments have remained unchanged for two decades, and many local communities say they no longer trust the system.

The findings, published in Conservation Letters, suggest that governments risk undermining conservation gains when they fail to address the long-term financial and social costs that wildlife recovery can place on local residents.

A Revolutionary Approach to Predator Conservation

Dr. Hanna Pettersson of the University of York’s Leverhulme Centre for Anthropocene Biodiversity explained how the program differed from traditional compensation systems.

“Implemented in 1996, the scheme was at the time revolutionary. Instead of paying reindeer herders for damages caused by predators, the government paid communities for coexisting with them, whether or not damage actually occurs.

“The idea is to tie an income to the presence of the predator, providing an incentive to find ways to live alongside them, thus decreasing conflicts and improving social justice.

“Initial findings showed encouraging results of the scheme, namely a marked increase of the wolverine population, but after studying 30 years of data from the scheme, we have shown that this success has not been sustained.”

To investigate the program’s long-term impact, Dr. Pettersson accompanied wildlife rangers working in the Arctic. The researchers also combined ecological monitoring records with interviews conducted in Norrbotten, Sweden’s northernmost county.

Their results point to growing challenges within the program and raise broader concerns for conservation efforts elsewhere.

Wolverine Numbers Decline in Northern Sweden

The study found that wolverines are spreading into southern parts of Sweden while declining in regions that historically supported the largest populations.

In the early 2000s, Norrbotten accounted for roughly two-thirds of all documented wolverine reproductions in Sweden. Today, that figure has fallen to less than one-third, and the county regularly fails to meet minimum conservation targets.

Researchers say stagnant funding has become a major issue.

Dr. Pettersson said: “The payments to the reindeer herders from the scheme have remained frozen at 200,000 SEK per predator reproduction since 2002, but due to rising costs and meat prices, the real value of the payment has approximately halved over the last two decades.

“While the Sámi Parliament calculates the legal payout should be at least 480,000 SEK to comply with the law, the government offered only a 25,000 SEK increase in 2024.”

Climate Change and Tracking Challenges

The research also identified climate change as an additional obstacle. Shifting snow conditions across the Arctic have made wolverine tracks harder to detect and document.

As a result, official counts may not fully reflect the true number of animals. Researchers noted that many apparent wolverine sightings were rejected because they did not satisfy strict documentation requirements.

According to Dr. Pettersson, these challenges illustrate the need for governments to adapt conservation programs as conditions change.

“If a government fails to adapt payments to rising costs of coexistence, the burden is shifted onto local, often marginalized, communities, who in this case are already straining under the cumulative impacts of mining, forestry, and climate change.

“It is a warning sign for other global conservation efforts. Governments must plan ahead and adapt interventions to changing conditions and local needs.”

A team from XPANCEO, working with scientists from the National University of Singapore and the University of Chemistry and Technology, Prague, has reported a major advance in that effort. Their study focuses on a layered crystal called molybdenum oxychloride (MoOCl₂), which displays a collection of unusual optical properties that could help dramatically shrink future optical devices.

Published in Nano Letters, the research presents the first experimental mapping of the crystal’s optical behavior. The findings show that MoOCl₂ exhibits the strongest light-bending effect ever measured in a natural material, potentially opening a path toward much smaller and more capable optical technologies.

A Crystal That Acts Like Metal and Glass

Researchers describe MoOCl₂ as a kind of optical “chameleon.” Its behavior changes depending on how the crystal is oriented.

When positioned one way, it reflects light much like a metal. Rotate it by 90 degrees, and it becomes transparent like glass. This unusual characteristic stems from its extreme optical anisotropy, meaning its properties vary dramatically depending on direction.

The crystal also has an in-plane birefringence value of approximately 2.2, allowing it to split and bend light with exceptional efficiency. For XPANCEO, this could make it possible to perform the sophisticated light control needed for AR displays using materials that are thousands of times thinner than a human hair.

Rare Light-Slowing Effect Found in Visible Light

The researchers also identified a rare epsilon-near-zero point at 512 nm (green light).

At this point, part of the material’s optical response falls almost to zero. As a result, light effectively slows down while the electric field inside the crystal becomes stronger. This combination can significantly enhance interactions between light and matter.

For integrated photonic chips, this effect could be especially valuable. Stronger light-matter interactions may enable faster data processing while using much less power.

Why Scientists Are Interested in MoOCl₂

Physicists have been studying MoOCl₂ for several years because of its unusual electronic structure.

The material is classified as a “bad metal” and contains one-dimensional chains of molybdenum atoms. These chains allow electrons to move more easily in one direction than another. As a result, the crystal behaves like a metal along one axis and like a dielectric material along the perpendicular axis, creating its exceptionally strong anisotropy.

Previous studies published in Science and Nature Communications had already observed tightly confined light waves called hyperbolic plasmon polaritons traveling through the crystal. Those experiments showed that MoOCl₂ could guide light in highly directional and unexpected ways.

However, an important piece of the puzzle was still missing. Scientists could observe the optical effects, but they had not directly measured the material’s full optical constants. Without those measurements, designing practical devices based on the crystal remained much more difficult.

Mapping the Crystal’s Optical Properties

The new work provides those missing measurements.

The researchers found that near 512 nanometers in the green region of the visible spectrum, one component of the crystal’s optical response approaches zero. In practical terms, this can intensify the electric field inside the material and slow light down, squeezing electromagnetic energy into a very small volume and boosting light-matter interactions.

This phenomenon is known as a visible-light epsilon-near-zero (ENZ) point. While many materials exhibit ENZ behavior only in the deep ultraviolet or mid-infrared regions, MoOCl₂ reaches this state within the visible spectrum. That is particularly important because many existing technologies, including lasers, microscopes, cameras, and sensing systems, already operate in this range.

“Observing a phenomenon is the first step, but engineering requires precise numbers,” said Dr. Valentyn Volkov, founder and CTO of XPANCEO and corresponding author of the study. “By rigorously measuring the complete dielectric tensor of MoOCl₂, our work provides the experimental foundation needed to understand why this material behaves the way it does and to design around it with greater confidence. That makes it a valuable scientific result for the field, with possible relevance across compact polarization optics, nonlinear devices, and, in the longer term, highly miniaturized integrated systems including smart contact lenses.”

Shrinking Future Optical Hardware

The detailed optical map also highlights the material’s potential for further miniaturization of optical technologies.

Because of its strong structural anisotropy, MoOCl₂ functions as a natural hyperbolic medium. In simple terms, this allows light to travel through the crystal in highly directional nanoscale paths without diffracting (or scattering), a key requirement for building smaller optical circuits.

Its ability to operate in the visible spectrum further strengthens its appeal for integrated photonic chips, where light must be routed, filtered, and concentrated within extremely small spaces.

The researchers point to several possible applications. These include ultrathin broadband polarizers that control the direction of light in compact optical systems, as well as sub-diffractional waveguides capable of guiding light through spaces smaller than those allowed by conventional optics.

The findings also suggest opportunities in nonlinear nanophotonics, where intense light-matter interactions can be used to create new colors of light or process optical signals more efficiently.

One approach that has drawn growing interest is intermittent energy restriction (IER), a form of dieting in which periods of reduced calorie intake are followed by periods of more typical eating. Research published in 2023 suggests that this strategy may do more than reduce body weight. It may also shift the relationship between gut bacteria and brain activity in ways that are closely tied to appetite and food behavior.

“Here we show that an IER diet changes the human brain-gut-microbiome axis. The observed changes in the gut microbiome and in the activity in addition-related brain regions during and after weight loss are highly dynamic and coupled over time,” said last author Dr. Qiang Zeng, a researcher at the Health Management Institute of the PLA General Hospital in Beijing.

Intermittent fasting and the brain

To explore what happens inside the body during weight loss, the researchers studied 25 adults with obesity in China. The volunteers, who were about 27 years old on average, had a BMI between 28 and 45.

The team used several tools to track changes over time. Stool samples were analyzed with metagenomics to measure the composition of the gut microbiome. Blood tests were used to monitor metabolic and physiological changes. The researchers also used functional magnetic resonance imaging (fMRI) to examine activity in brain regions involved in appetite, emotion, attention, learning, inhibition, and reward.

“A healthy, balanced gut microbiome is critical for energy homeostasis and maintaining normal weight. In contrast, an abnormal gut microbiome can change our eating behavior by affecting certain brain area involved in addiction,” explained coauthor Dr. Yongli Li from the Department of Health Management of Henan Provincial People’s Hospital in Henan, China.

A carefully controlled weight loss program

The study began with a 32 day high controlled fasting phase. During this period, participants received meals designed by a dietitian. Their calorie intake was gradually reduced in steps until it reached about one quarter of their basic energy needs.

This was followed by a 30 day low controlled fasting phase. During this stage, participants were given a list of recommended foods rather than fully prepared meals. Those who followed the plan exactly would consume 500 calories per day for women and 600 calories per day for men.

By the end of the intervention, participants had lost an average of 7.6 kilograms, equal to about 7.8% of their starting body weight. They also had reductions in body fat and waist circumference.

The metabolic improvements extended beyond weight. Blood pressure fell, as did fasting plasma glucose, total cholesterol, HDL, LDL, and the activity of key liver enzymes. According to the researchers, these changes suggest that intermittent energy restriction may help reduce obesity related problems such as hypertension, hyperlipidemia, and liver dysfunction.

Brain and gut changes moved together

The researchers found that the weight loss program was linked to lower activity in several brain regions involved in appetite and addiction related behavior. These changes may help explain why dieting affects not only body size, but also food cravings, self control, and the drive to eat.

At the same time, the gut microbiome shifted. The abundance of Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacterokles uniformis rose sharply. Escherichia coli decreased.

Further analysis suggested that certain microbes were connected with activity in specific brain areas. The abundance of E. coli, Coprococcus comes, and Eubacterium hallii was negatively associated with activity in the brain’s left orbital inferior frontal gyrus, a region involved in executive function and willpower during weight loss.

Other bacteria showed the opposite pattern. P. distasonis and Flavonifractor plautii were positively linked with brain regions involved in attention, motor inhibition, emotion, and learning.

These findings point to a striking possibility: as people lose weight, the gut microbiome and the brain may change together. The study cannot prove whether gut bacteria drive the brain changes, whether the brain drives microbial changes, or whether another factor influences both. Still, the results add to evidence that weight control is not just a matter of willpower or calories. It may involve a changing biological conversation between the gut and the brain.

A two way conversation inside the body

“The gut microbiome is thought to communicate with the brain in a complex, two-directional way. The microbiome produces neurotransmitters and neurotoxins which access the brain through nerves and the blood circulation. In return the brain controls eating behavior, while nutrients from our diet change the composition of the gut microbiome,” said coauthor Dr. Xiaoning Wang from the Institute of Geriatrics of the PLA General Hospital.

This two way communication may help explain why obesity is so difficult to treat. Hunger, cravings, mood, reward, and metabolism are all shaped by biological signals. The gut microbiome can produce compounds that influence inflammation, metabolism, and nervous system activity. The brain, in turn, helps regulate food choices and eating behavior.

The 2023 findings suggest that successful weight loss may involve changes across this entire system rather than in one isolated organ.

What later research adds

Research published after the 2023 study has continued to support the idea that fasting can influence the gut microbiome, although the evidence remains complex. A 2024 systematic review of human studies found that intermittent fasting appears to affect gut microbial richness, diversity, and composition. However, the authors also noted that results varied widely between studies, and more research is needed to determine which changes are truly beneficial for health.

Another 2024 clinical study compared intermittent fasting combined with protein pacing to continuous calorie restriction in adults with overweight or obesity. Both diets reduced calorie intake, but the fasting and protein pacing group showed greater weight loss and more pronounced shifts in the gut microbiome. The researchers reported increases in microbes and metabolic signals associated with improved body composition and fat loss.

Together, these later findings strengthen the broader picture: fasting based interventions may reshape the gut microbiome in meaningful ways. However, they also show that the details matter. The type of fasting, calorie intake, protein intake, fiber intake, meal timing, and individual biology may all influence the outcome.

The next question for weight loss research

The original 2023 study was small and correlational, so it cannot show cause and effect. It also focused on a specific group of participants and a short term intervention. Larger and longer studies will be needed to determine whether certain microbes or brain regions can reliably predict who will lose weight, who will keep it off, and which diets work best for different people.

Coauthor Dr. Liming Wang, likewise from the Health Management Institute in Beijing, said: “The next question to be answered is the precise mechanism by which the gut microbiome and the brain communicate in obese people, including during weight loss. What specific gut microbiome and brain regions are critical for successful weight loss and maintaining a healthy weight?”

For now, the research offers a more detailed view of what may happen during intermittent fasting. Weight loss may not be limited to shrinking fat stores. It may also involve a synchronized shift in gut bacteria, metabolism, and brain activity that changes how the body responds to food.