Chapter 13. Homeostasis: Active Regulation of the Internal Environment

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By Christina Caron Dr. Kyle Staller is a gastroenterologist, so it may be surprising that many of his patients come to him complaining not only about stomach trouble but about their brains, too. Irritable bowel syndrome and other digestive dysfunction can be accompanied by a mental haze. People experiencing constipation and bloating, for example, may describe “a sense of heaviness or being weighed down both physically and mentally,” said Dr. Staller, who works at Massachusetts General Hospital in Boston. “So many of my patients talk about problems like fatigue, brain fog and feeling sluggish,” he added. Scientists are making progress in understanding how the pathway between the brain and the digestive system influences our overall health. They call it the gut-brain axis, and it has been shown to play a big role in immune system support, anxiety, depression, metabolism and disease prevention. It can also affect mental clarity. We asked scientists and clinicians what to know about the gut and brain fog. How does the gut-brain axis work? There are thousands of fibers running from the brain to the abdomen that are known as the vagus nerve. It is a primary conduit of the gut-brain axis. And as the main nerve of the parasympathetic nervous system, it helps the body rest, digest and deter inflammation. Signals also travel back and forth between the gut and brain via stress hormones and immune cells. Crucially, gut bacteria produce chemical messengers (called neurotransmitters) like serotonin, dopamine and GABA that affect the nervous system. When they enter the bloodstream or stimulate the vagus nerve, they can help improve mood, drive motivation, and calm the nervous system. © 2026 The New York Times Company

Keyword: Attention
Link ID: 30243 - Posted: 05.16.2026

By Kate Golembiewski By watching their peers, dolphins learn to capture fish in empty conch shells, then ferry the shells up to the water’s surface in order to eat. Octopuses can master experimental tasks by watching their tankmates in the laboratory. Crows follow the cues of others in their flock to attack specific humans who have harassed fellow crows in the past. Scientists call it “social learning,” and it essentially means monkey see, monkey do, an adage that turns out to apply to many animals beyond just primates. Now, a study of Australia’s sulfur-crested cockatoos shows that the birds employ social learning to understand whether unfamiliar foods are safe to eat. In more forested areas of the cockatoos’ native range in Australia, New Guinea, and Indonesia, these mohawked parrots eat plant roots, seeds, fruits and insect larvae. But the birds have learned to thrive in urban environments. “They’re everywhere in Sydney,” said Julia Penndorf, a behavioral ecologist and lead author of the study in PLOS Biology, who encountered the birds as a postdoctoral researcher at the Australian National University in Canberra. In urban areas, the birds have expanded their diets to include nonnative plants and nuts, including almonds and sunflower seeds people offer to them, and they can be seen prying the lids off garbage bins in order to forage. “The big issue with urban birds is, they kind of eat everything,” Dr. Penndorf, who now works at the University of Exeter, said. This expanded diet is high-risk, high-reward: the birds have more options for food, but there’s always a chance that strange new snacks might be poisonous. © 2026 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 30229 - Posted: 05.02.2026

By Gina Kolata Before the new obesity drugs came on the market, almost no one used the term food noise. Researchers studying and developing drugs like Ozempic, Wegovy, Mounjaro and Zepbound analyzed doses, side effects, weight loss and improvements in conditions such as diabetes, heart disease and sleep apnea. Incessant thoughts about food and internal dialogues about what to eat, what not to eat, when to eat, how to resist eating — these were not on the research agenda. But if the obesity-drug researchers weren’t talking about food noise, people taking GLP-1s had a lot to say about it. For as long as they could remember, users of the drugs said, they had been plagued by food noise. But they thought it was just a normal part of life. They thought everyone had it. Until they took one of the new drugs. Suddenly, food noise was silenced. And that effect is leading to new questions about the drugs. If researchers can clarify the source of this inner buzz and what makes it go away, that could lead to a clearer understanding of what causes obesity in the first place. ‘You Don’t Want the Salad’ People who struggle with their weight describe relentless thoughts of food. Lena Smith Parker, 53, of Hamden, Conn., spent decades dieting and regaining weight. All the while, she said, she was plagued by internal voices urging her to eat and shaming her for eating. © 2026 The New York Times Company

Keyword: Obesity
Link ID: 30221 - Posted: 04.29.2026

Ian Sample Science editor Changes to microbes that live in the gut can identify people at greater risk of Parkinson’s disease long before symptoms develop, according to work that also raises hopes for new therapies. Researchers discovered signature changes in the gut microbiome that are more pronounced in people with a genetic risk for Parkinson’s and even more stark in those diagnosed with the disease. The signature could help doctors spot patients at risk of Parkinson’s years before they display clear symptoms and suggests that healthier diets and treatments that reshape the microbiome might prevent or delay the disease. Prof Anthony Schapira, the head of clinical and movement neurosciences at University College London and lead investigator on the study, said it was the first time a microbial signature in Parkinson’s patients had been seen in people with a genetic susceptibility but had yet to develop symptoms. The signature appears to become stronger as the disease progresses. “These same changes can be found in a small proportion of the general population that may put them at increased risk,” Schapira said. Cases of Parkinson’s have doubled in the past 25 years, with more than 8.5 million people globally now living with the condition. The disease causes progressive brain damage, leading to tremors, slow movement and stiff and inflexible muscles. Patients often experience depression, anxiety, sleep and memory problems, and difficulty with balance. © 2026 Guardian News & Media Limited

Keyword: Parkinsons
Link ID: 30209 - Posted: 04.22.2026

By Jamie Ducharme More than 10 percent of U.S. adults take GLP-1 drugs. But not all of them are taking full doses. Around one in seven users has “microdosed” injections, a recent survey by the health tracking app Evidation found. Some take tiny portions for practical reasons, such as cutting costs. Others have loftier ambitions: They hope to harness the drugs’ powerful effects to achieve better health and longer lives without losing a lot of weight or experiencing side effects such as GI issues and muscle loss. Medications such as Ozempic and Wegovy mimic the body’s GLP-1 hormone, which helps regulate appetite, metabolism and blood sugar. That has made the drugs blockbuster treatments for type 2 diabetes and obesity. But to date, “there is no rigorous scientific data to support microdosing,” says bariatric medicine specialist Katy Williams of the University of Missouri Health Care in Jefferson City. That hasn’t stopped some intrepid biohackers from trying it, though. Companies like AgelessRx, a longevity-focused telehealth clinic, explicitly sell GLP-1 microdoses for this purpose, advertising them as “a powerful new path to promoting long-term wellness.” There is some research to suggest GLP-1s can promote healthy aging by improving overall health. The drugs have been found to reduce inflammation and oxidative stress, lower risks of major cardiovascular problems, lower cancer risk and more. Such findings have prompted scientists to study the drugs as potential treatments for illnesses as diverse as Alzheimer’s disease and arthritis. Some experts have even wondered whether the drugs’ systemic effects might slow cellular aging and prevent age-related chronic conditions, potentially making them the first true longevity drugs to hit the market. © Society for Science & the Public 2000–2026.

Keyword: Obesity
Link ID: 30167 - Posted: 03.21.2026

Mariana Lenharo The weight-loss drugs that took the world by storm a few years ago have a drawback for anyone afraid of needles: they must be injected weekly. But scientists have been racing to perfect anti-obesity pills — which are now coming to market. An oral anti-obesity drug called orforglipron is likely to be approved by US regulators by the end of April, pharmaceutical analysts say. In December, a pill version of the obesity drug semaglutide won US regulatory approval. Both drugs belong to the class of therapies called glucagon-like peptide-1 (GLP-1) receptor agonists. Semaglutide, sold as Wegovy, is made by Novo Nordisk in Bagsværd, Denmark; orforglipron is made by Eli Lilly and Company in Indianapolis, Indiana. Clinical-trial results have been positive. After around one year of treatment at the highest dosage, people taking orforglipron lost, on average, about 11% of their body weight1, and those taking semaglutide pills lost almost 14%2. But it’s uncertain whether pills could one day replace the GLP-1 pens that have become a weight-loss staple. Oral drugs face formidable developmental challenges, and several injected drugs cause greater weight loss than does either orforglipron or oral semaglutide: the approved injectable drug Zepbound, for example, leads to weight loss of up to 21% of body weight3. “It’s encouraging, and it’s fantastic to have double-digit weight loss with a pill,” says Daniel Drucker, an endocrinologist at the University of Toronto in Canada. “But so far, rather than replace, I would say they’re going to complement the options that we have.” There’s a good reason why the original GLP-1 receptor agonists, which mimic the natural hormone glucagon-like peptide-1, were sold in injectable form. The drugs are composed of peptides, which are relatively large molecules. Because of their size, digestive enzymes quickly break them down, and the intestinal lining limits their entry into the bloodstream. © 2026 Springer Nature Limited

Keyword: Obesity
Link ID: 30163 - Posted: 03.19.2026

By Catherine Offord Scientists have plenty of ideas about why aging impairs memory. Reductions in blood flow in the brain, shrinking brain volume, and malfunctioning neural repair systems have all been blamed. Now, new research in mice points to another possible culprit: microbes in the gut. In a study published today in Nature, scientists show how a bacterium that is particularly common in older animals can drive memory loss. This microbe makes compounds that impair signaling along neurons connecting the gut with the brain, dampening activity in brain regions associated with learning and memory, the team found. “This is a tour de force,” says Haijiang Cai, a neuroscientist at the University of Arizona who studies gut-brain communication and was not involved in the work. “They define the pathway all the way from aging and bacteria … to cognitive function—it’s really impressive.” However, he and others emphasize it remains to be seen whether a similar mechanism exists in humans—and if so, how important it is compared with other drivers of cognitive decline. Research on the so-called gut-brain axis has exploded in recent decades. Multiple studies have identified differences in microbiome composition between healthy people and those with cognitive disorders such as Alzheimer’s disease. This kind of research can’t establish cause and effect, though, and the literature is rife with conflicting results. Some groups have used animal experiments to probe the microbe-memory link. In the new study, Stanford University researchers Christoph Thaiss and Maayan Levy tinkered with the microbiomes of young mice—either by housing them with older animals or feeding them these animals’ poop—and then gave them memory tests. For example, one such test rates animals higher if they spend more time exploring new objects than those they’ve seen before. © 2026 American Association for the Advancement of Science.

Keyword: Learning & Memory; Obesity
Link ID: 30162 - Posted: 03.14.2026

By Catherine Offord Scientists have plenty of ideas about why aging impairs memory. Reductions in blood flow in the brain, shrinking brain volume, and malfunctioning neural repair systems have all been blamed. Now, new research in mice points to another possible culprit: microbes in the gut. In a study published today in Nature, scientists show how a bacterium that is particularly common in older animals can drive memory loss. This microbe makes compounds that impair signaling along neurons connecting the gut with the brain, dampening activity in brain regions associated with learning and memory, the team found. “This is a tour de force,” says Haijiang Cai, a neuroscientist at the University of Arizona who studies gut-brain communication and was not involved in the work. “They define the pathway all the way from aging and bacteria … to cognitive function—it’s really impressive.” However, he and others emphasize it remains to be seen whether a similar mechanism exists in humans—and if so, how important it is compared with other drivers of cognitive decline. Research on the so-called gut-brain axis has exploded in recent decades. Multiple studies have identified differences in microbiome composition between healthy people and those with cognitive disorders such as Alzheimer’s disease. This kind of research can’t establish cause and effect, though, and the literature is rife with conflicting results. Some groups have used animal experiments to probe the microbe-memory link. In the new study, Stanford University researchers Christoph Thaiss and Maayan Levy tinkered with the microbiomes of young mice—either by housing them with older animals or feeding them these animals’ poop—and then gave them memory tests. For example, one such test rates animals higher if they spend more time exploring new objects than those they’ve seen before. © 2026 American Association for the Advancement of Science.

Keyword: Learning & Memory; Obesity
Link ID: 30161 - Posted: 03.14.2026

Denis Campbell Weight loss drugs could help people avoid getting addicted to alcohol, tobacco and drugs such as cannabis and cocaine, a study has found. They could also reduce the risk of people already addicted to illicit substances having an overdose, ending up in hospital or dying, according to research published in the British Medical Journal. Glucagon-like peptide-1 receptor agonists used to treat type 2 diabetes and obesity, such as Mounjaro and Ozempic, are thought to work by influencing the brain’s reward pathways in order to cut cravings. They help people feel fuller by mimicking the natural substance released after eating. The US study analysed 606,434 US veterans with type 2 diabetes, who were monitored for up to three years. It found that GLP-1s reduced the risk of alcohol-related disorders in those with no history of substance use by 18% and of using cannabis (14%), cocaine (20%), nicotine (20%) and opioids (25%), compared with those on other sodium-glucose cotransporter-2 drugs also used to treat diabetes. Weight loss drugs also reduce the risk of people already using substances from overdosing (39%), needing emergency help in A&E (31%) or dying (50%). “This study adds to emerging research exploring whether GLP-1 medicines may influence brain pathways involved in reward and addiction”, said Prof Claire Anderson, the president of the Royal Pharmaceutical Society, which represents 35,500 UK pharmacists. She added: “As this was an observational study, it is important to be clear that it does not show these medicines prevent or treat addiction. Further research, including clinical trials, will be needed to understand whether GLP-1 medicines have a direct effect.” © 2026 Guardian News & Media Limited

Keyword: Drug Abuse; Obesity
Link ID: 30150 - Posted: 03.07.2026

By Hannah Thomasy In 1774, British physician-scientist Charles Blagden received an unusual invitation from a fellow physician: to spend time in a small room that was hotter, he wrote, “than it was formerly thought any living creature could bear.” Many people may have been appalled by this offer, but Blagden was delighted by the opportunity for self-experimentation. He marveled as his own temperature remained at 98 degrees Fahrenheit (approximately 37 degrees Celsius), even as the temperature of the room approached 200°F (about 93°C). Today, this ability to maintain a stable body temperature — called homeothermy — is known to exist among myriad species of mammals and birds. But there are also some notable exceptions. The body temperature of the fat-tailed dwarf lemur, for example, can fluctuate by nearly 45°F (25°C) over a single day. In fact, a growing body of research suggests that many more animals than scientists once appreciated employ this flexible approach — heterothermy — varying their body temperature for minutes, hours or weeks at a time. This may help the animals to persist through all sorts of dangers. “Because we’re homeotherms, we assume all mammals work the way we do,” says Danielle Levesque, a mammalian ecophysiologist at the University of Maine. But in recent years, as improvements in technology allowed researchers to more easily track small animals and their metabolisms in the wild, “we’re starting to find a lot more weirdness,” she says. The most extreme — and well-known — form of heterothermy is classic hibernation, which has been most extensively studied in critters who use it to save energy and so survive the long, cold winters of the Northern Hemisphere. These animals enter long periods of what scientists call deep torpor, when metabolism slows to a crawl and body temperature can drop to just above freezing.

Keyword: Evolution
Link ID: 30137 - Posted: 02.25.2026

By Emma Gometz Caribou, large deer that are native to the northernmost parts of the world (and sometimes called reindeer), are the only deer whose females grow antlers. In a study published today, researchers observed behavior that might explain why: female caribou appear to gnaw on shed antlers as a kind of postbirthing supplement. Caribou migrate huge distances every year between the places where they graze during the winter and the grounds where they calve in the spring. They can walk thousands of miles per year and likely have the longest terrestrial migration of any animal. Caribou mothers complete these extremely long migrations with antlers on their head and a calf in their womb. The period is very nutritionally demanding for them but culminates with a reserve stock of supplements when they need it the most. The researchers behind the new study figured this out when they observed bite marks in more than 80 percent of the 1,500 caribou antlers that littered the part of the Arctic National Wildlife Refuge in northeastern Alaska where the deer give birth. “[Caribou] are just really going after the antlers. They are highly selective,” says study co-author Joshua Miller, a paleoecologist at the University of Cincinnati. Female caribou shed their antlers just days before giving birth. Miller and co-author Madison Gaetano, a conservation paleobiologist, say that the findings suggest that female caribou are essentially banking nutrients in the form of antlers before they give birth and then gnawing on their freshly shed antlers to get a boost of protein, calcium and phosphorus they need to make up for having less time to graze as they nurse their calves. © 2025 SCIENTIFIC AMERICAN,

Keyword: Sexual Behavior
Link ID: 30136 - Posted: 02.25.2026

By Delthia Ricks Susan E. Leeman, who helped reshape scientific understanding of how the brain sends chemical signals throughout the body, did not hesitate to leave the laboratory when her research demanded it — even if it meant visiting slaughterhouses. In the late 1960s, while running a small lab at Brandeis University, she was trying to isolate a stress hormone and needed large quantities of the bovine hypothalamus, a cow’s version of the structure found deep in all mammalian brains. When supplies ran short at a local meatpacker in Boston, Dr. Leeman traveled to Chicago, home at the time to the sprawling Union Stock Yards, to secure fresh tissue. What ultimately emerged was not the hormone that she sought but an elusive chemical called Substance P. Discovered decades earlier but never fully understood, it was finally identified by Dr. Leeman in 1970 as a neuropeptide, released by cells in the brain or spinal cord in response to pain. Three years later, she identified another neuropeptide. The two discoveries established her as a leading figure in neuroendocrinology. Dr. Leeman died on Jan. 20 in Manhattan, at the home of her daughter Eve Leeman, where she had been living. She was 95. Her death was confirmed by another daughter, Jennifer Leeman. Although Substance P was identified in 1931 by Ulf von Euler and John Gaddum, researchers working in London, it was Dr. Leeman who discovered that it was a neuropeptide — a tiny, protein-like molecule released by neurons, or nerve cells in the brain and spinal cord, that transmits signals to target tissues. It was the first neuropeptide discovered in what would become a large class known as tachykinins. Dr. Leeman found that Substance P relays pain signals and amplifies the sensation of pain by triggering inflammation. It has since been linked to chronic pain syndromes, arthritis pain and migraines. © 2026 The New York Times Company

Keyword: Pain & Touch
Link ID: 30135 - Posted: 02.25.2026

By Meghan Rosen Ozempic’s key ingredient may act directly on cartilage to repair creaky joints. In mice and people, semaglutide can ease symptoms of the joint disease osteoarthritis and thicken the cartilage pillowed between bones, researchers report February 9 in Cell Metabolism. Thicker cartilage suggests the tissue is being rebuilt, says Di Chen, a physician and biologist at Shenzhen University of Advanced Technology in China. “That’s a good thing,” he says. “That’s the key thing.” More cartilage means more cushion, which means less bone-on-bone grinding and less pain. Osteoarthritis is the most common form of arthritis, affecting more than 500 million people worldwide. The disease can affect the hands, knees, hips and other joints, causing severe pain as cartilage wears away and tissues inflame. There’s no cure, and no medications that prevent it from becoming worse. Doctors can only help patients try to manage pain, Chen says. Scientists think weight loss can help alleviate symptoms by reducing the load on joints. That’s why semaglutide, the smash weight loss drug in Ozempic and Wegovy, is considered a contender for osteoarthritis treatment. And indeed, in 2024, a clinical trial in people with obesity reported that the drug improved joint pain and function. Doctors assumed those benefits were due to weight loss, Chen says. His team wasn’t so sure. The researchers conducted a similar study in mice with a form of osteoarthritis. One group received semaglutide, the other did not. In the drug-free mice, Chen’s team restricted food intake to match that of the semaglutide group. Both groups shed weight, but only the treated mice saw joint-based benefits. These mice had less pain, less broken-down cartilage and more cartilage growth, the team found. The results suggest that weight loss isn’t driving semaglutide’s benefits. © Society for Science & the Public 2000–2026.

Keyword: Neuroimmunology; Obesity
Link ID: 30129 - Posted: 02.21.2026

Mariana Lenharo Exercise pumps up your muscles — but it might also be pumping up your neurons. According to a study published today in Neuron1, repeated exercise sessions on a treadmill strengthen the wiring in a mouse’s brain, making certain neurons quicker to activate. This ‘rewiring’ was essential for mice in the study to gradually improve their running endurance. The work reveals that the brain — in mice and, presumably, in humans — is actively involved in the development of endurance, the ability to get better at a physical activity with repeated practice, says Nicholas Betley, a neuroscientist at the University of Pennsylvania in Philadelphia, and a co-author of the paper. “You go for a run, and your lungs expand, your heart gets pumping better, your muscles break down and rebuild. All this great stuff happens, and the next time, it gets easier,” Betley says. “I didn’t expect that the brain was coordinating all of that.” Betley and his colleagues were curious about what happens in the brain as people get stronger through exercise. They decided to focus on the ventromedial hypothalamus, a brain region that regulates appetite and blood sugar. The team then zeroed in on a group of neurons in that region that produce a protein called steroidogenic factor 1 (SF1), which is known to play a part in regulating metabolism2. A previous study3 found that the deletion of the gene that codes for SF1 impairs endurance in mice. © 2026 Springer Nature Limited

Keyword: Obesity; Learning & Memory
Link ID: 30120 - Posted: 02.14.2026

Yuki Noguchi At just over 5 foot, 5 inches, Christie Woodard weighs a lean 125 pounds. She's also open about relying on a low-dose GLP-1 to keep her weight there. She says sometimes people question why she's on the drug, "because they look at me and think I'm at healthy weight, or maybe they even think I'm thin." What people don't see is Woodard's previous struggles with obesity, which began in her 30s, and landed her at 260 pounds. She took up running half-marathons, but at that weight, it was painful. "I was not fast," she says. "I had massive issues; I was in physical therapy constantly. I tore my meniscus." Woodard, now 53 and living in Easton, Md., got gastric bypass surgery four years ago and cut her weight in half. Elated, she set a goal of completing half-marathons in all 50 states. Her weight remained stable until last year, when pounds began creeping back, despite adhering to a strict diet and lots of exercise. "I feel it in my knees, and mainly I feel it in my soul," she says. "I feel it in my confidence. It's messing with my head in a big way. I was terrified that I was going to go back to what I was." So her bariatric surgeon, Dr. Betsy Dovec, prescribed a low dose of the drug Zepbound, even though Woodard's body mass index didn't technically classify her as overweight. Dovec says Woodard isn't her only normal-weight patient on GLP-1s. "I prescribe medications for all types of people," she says. Though, she clarifies, she does not give the drugs to people for purely aesthetic reasons, like someone trying to shed a few pounds before an event, for example. © 2026 npr

Keyword: Obesity
Link ID: 30118 - Posted: 02.14.2026

By Molly Glick Not long after upending federal diet guidelines in order to prioritize “real food” on our plates, United States Health and Human Services Secretary Robert F. Kennedy Jr. has offered a new piece of questionable advice. During a tour to promote these dietary recommendations, Kennedy recently claimed that a keto diet can cure schizophrenia—an assertion that experts have quickly thrown cold water on. The ketogenic diet promotes fat-rich meals and low amounts of carbohydrates. While keto eating has skyrocketed in popularity in recent years—it ranked the most Googled diet in the U.S. in 2020—it was initially designed in the early 20th century for patients with epilepsy. More recent studies have confirmed that the diet is effective for certain types of epilepsy because it can control seizures. Meanwhile, we have much less evidence for its impacts on symptoms of schizophrenia. So far, small studies have offered some early evidence that ketogenic diets may help people with the condition. “There is currently no credible evidence that ketogenic diets cure schizophrenia,” Mark Olfson, a psychiatrist at Columbia University, told The New York Times. Kennedy also proclaimed that the diet can essentially cure bipolar disorder, according to studies he recently read. But as with schizophrenia, keto’s impacts on bipolar disorder have only been examined in limited numbers of patients so far. Preliminary findings have also hinted that a keto diet could ease symptoms of depression. It may offer “small antidepressant benefits” for people who don’t respond to medication, according to a recently published JAMA Psychiatry paper. But this work is in the early stages as well and remains far from conclusive. © 2026 NautilusNext Inc.

Keyword: Schizophrenia; Depression
Link ID: 30109 - Posted: 02.07.2026

By Jake Buehler Though fearsome predators, snakes can go weeks or even months without eating. Now, scientists think they may know how they do it. Snakes have lost the genes to produce ghrelin, a key hormone that regulates appetite, digestion, and fat storage, researchers report today in Royal Society Open Biology. Chameleons and a group of desert lizards called toadhead agamas that also have huge spaces between meals have also lost the same genes, hinting that cutting off ghrelin is a key way to excel at fasting, possibly by suppressing appetite and holding onto fat stores. “I give [the researchers] a lot of credit for looking more deeply into the data that was staring us all in the face—myself included,” says Todd Castoe, a genomicist at the University of Texas at Arlington not involved with the study. The hormone is ubiquitous across vertebrates, from fish to mammals. So finding that reptiles have repeatedly ditched it is “pretty remarkable,” he says. When scientists first discovered ghrelin nearly 30 years ago, they thought this “hunger hormone” could be key to fighting obesity in humans. But it hasn’t been that simple. Since then, researchers have found that ghrelin has a complicated role within a network of hormones constantly tweaking hunger and energy stores. And even though ghrelin is commonly found in vertebrates, it’s been unclear how it has evolved across various groups of vertebrates. So in the new study, Rui Resende Pinto, an evolutionary biologist at the University of Porto, and his colleagues focused on reptiles, many of which can go long periods without food. The researchers scanned the genomes of 112 species. In snakes, chameleons, and toadhead agamas, ghrelin genes were either missing or so warped by mutations they could no longer encode the hormone, the team found. The degree of the genes’ erosion also varied considerably between snake families: Some snakes such as boas and pythons had malformed ghrelin genes, but others, such as vipers, cobras, and their relatives, barely had anything left.

Keyword: Obesity; Evolution
Link ID: 30104 - Posted: 02.04.2026

By Diana Kwon edited by Jeanna Bryner By the time Maggie May, an Arkansas resident in her 30s, was admitted to a psychiatric clinic in 2024, she had been struggling for years with atypical anorexia nervosa, an eating disorder that leads to severe food restriction and profound disturbances in body image. (Her name has been changed for privacy.) She had already tried traditional interventions with a psychotherapist and a dietitian, but they had failed to improve her condition. So when May heard about a trial of a new and unconventional therapy, she jumped at the opportunity. The treatment was unusual in that alongside talk therapy, May underwent several sessions in a sensory-deprivation chamber: a dark, soundproof room where she floated in a shallow pool of water heated to match the temperature of her skin and saturated with Epsom salts to make her more buoyant. The goal was to blunt May’s external senses, enabling her to feel from within—focusing on the steady thudding of her heart, the gentle flow of air in and out of her lungs, and other internal bodily signals. The ability to connect with the body’s inner signals is called interoception. Some people are better at it than others, and one’s aptitude for it may change. Life events can also bolster or damage a person’s interoceptive skills. Sahib Khalsa, a psychiatrist and neuroscientist at the University of California, Los Angeles, and his colleagues think a disrupted interoception system might be one of the driving forces behind anorexia nervosa. So they decided to repurpose a decades-old therapy called flotation-REST (for “reduced environmental stimulation therapy”) and launched a trial with it in 2018. They hypothesized that in people with anorexia and some other disorders, an underreliance on internal signals may lead to an overreliance on external ones, such as how one looks in the mirror, that ultimately causes distorted body image, one of the key factors underlying these conditions. “When they’re in the float environment, they experience internal signals more strongly,” Khalsa says. “And having that experience may then confer a different understanding of the brain-body relationship that they have.” © 2025 SCIENTIFIC AMERICAN,

Keyword: Schizophrenia; Anorexia & Bulimia
Link ID: 30067 - Posted: 01.03.2026

By Emily Anthes In just a few short years, new diabetes and weight loss drugs like Ozempic, Wegovy and Mounjaro have taken the world by storm. In the United States, one in eight adults say they’ve tried one of these medications, which are known as GLP-1 drugs, and that number seems sure to rise as prices fall and new oral formulations hit the market. Fluffy and Fido could be next. On Tuesday, Okava Pharmaceuticals, a biopharmaceutical company based in San Francisco, is set to announce that it has officially begun a pilot study of a GLP-1 drug for cats with obesity. The company is testing a novel approach: Instead of receiving weekly injections of the drugs, as has been common in human patients, the cats will get small, injectable implants, slightly larger than a microchip, that will slowly release the drug for as long as six months. “You insert that capsule under the skin, and then you come back six months later, and the cat has lost the weight,” said Dr. Chen Gilor, a veterinarian at the University of Florida, who is leading the study. “It’s like magic.” Results are expected next summer. If they are promising, they could represent the next frontier for a class of drugs that has upended human medicine, and a potentially transformative treatment option for millions of pets. Some veterinarians have already begun administering human GLP-1 drugs, off label, to diabetic cats, and Okava is not the only company developing a product specifically for companion animals. “I think this is going to be the next big thing,” said Dr. Ernie Ward, a veterinarian and the founder of the Association for Pet Obesity Prevention. Veterinarians, he added, are “on the precipice of a complete new era in obesity medicine.” © 2025 The New York Times Company

Keyword: Obesity
Link ID: 30041 - Posted: 12.06.2025

Elie Dolgin Last April, neuroscientist Sue Grigson received an e-mail from a man detailing his years-long struggle to kick addiction — first to opioids, and then to the very medication meant to help him quit. The man had stumbled on research by Grigson, suggesting that certain anti-obesity medications could help to reduce rats’ addiction to drugs such as heroin and fentanyl. He decided to try quitting again, this time while taking semaglutide, the blockbuster GLP-1 drug better known as Ozempic. “That’s when he wrote to me,” says Grigson, who works at Pennsylvania State University College of Medicine in Hershey. “He said that he was drug- and alcohol-free for the first time in his adult life.” Stories like this have been spreading fast in the past few years, through online forums, weight-loss clinics and news headlines. They describe people taking diabetes and weight-loss drugs such as semaglutide (also marketed as Wegovy) and tirzepatide (sold as Mounjaro or Zepbound) who find themselves suddenly able to shake long-standing addictions to cigarettes, alcohol and other drugs. And now, clinical data are starting to back them up. Earlier this year, a team led by Christian Hendershot, a psychologist now at the University of Southern California in Los Angeles, reported in a landmark randomized trial that weekly injections of semaglutide cut alcohol consumption1 — a key demonstration that GLP-1 drugs can alter addictive behaviour in people with a substance-use disorder. More than a dozen randomized clinical studies testing GLP-1 drugs for addiction are now under way worldwide, with some results expected in the next few months. © 2025 Springer Nature Limited

Keyword: Drug Abuse; Obesity
Link ID: 30036 - Posted: 12.03.2025