Chapter 9. Homeostasis: Active Regulation of the Internal Environment

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By Molly Rains Over the past 50 years, worldwide obesity rates have tripled, creating a public health crisis so widespread and damaging that it is sometimes referred to as an epidemic. Most accounts put the roots of the problem firmly in the modern age. But could it have been brewing since before World War II? That’s one provocative conclusion of a study published today in Science Advances that purports to push the obesity epidemic’s origin back to as early as the 1930s. Historical measurements from hundreds of thousands of Danish youth show that in the decades before the problem was officially recognized, the heaviest members of society were already getting steadily bigger. The findings raise questions about the accepted narrative of the obesity epidemic, says Lindsey Haynes-Maslow, an obesity expert at the University of North Carolina at Chapel Hill who was not involved in the study. “This paper is an opportunity … to say maybe we’ve been looking at this wrong, maybe we should go back to the beginning—or, when was the beginning?” she says. Most epidemiologists trace that beginning to the 1970s, when health officials first observed an uptick in the prevalence of obesity—defined as a body mass index (BMI) above 30—in many Western nations. The crisis is usually blamed on the increased postwar availability of cheap, highly processed, and calorie-rich foods, as well as increasingly sedentary lifestyles and growing portion sizes. But University of Copenhagen epidemiologist Thorkild Sørensen was skeptical of that story. Years of slowly increasing body size typically precede obesity, and might show up in historical data, he suspected. And Sørensen wasn’t convinced that the so-called obesogenic diet and lifestyle were the only factors at play. Historical data, he hoped, could reveal whether other, yet-unknown factors had contributed to the crisis.

Keyword: Obesity
Link ID: 28909 - Posted: 09.16.2023

By Joanna Thompson= Like many people, Mary Ann Raghanti enjoys potatoes loaded with butter. Unlike most people, however, she actually asked the question of why we love stuffing ourselves with fatty carbohydrates. Raghanti, a biological anthropologist at Kent State University, has researched the neurochemical mechanism behind that savory craving. As it turns out, a specific brain chemical may be one of the things that not only developed our tendency to overindulge in food, alcohol and drugs but also helped the human brain evolve to be unique from the brains of closely related species. A new study, led by Raghanti and published on September 11 in the Proceedings of the National Academy of Sciences USA, examined the activity of a particular neurotransmitter in a region of the brain that is associated with reward and motivation across several species of primates. The researchers found higher levels of that brain chemical—neuropeptide Y (NPY)—in humans, compared with our closest living relatives. That boost in the reward peptide could explain our love of high-fat foods, from pizza to poutine. The impulse to stuff ourselves with fats and sugars may have given our ancestors an evolutionary edge, allowing them to develop a larger and more complex brain. “I think this is a first bit of neurobiological insight into one of the most interesting things about us as a species,” says Robert Sapolsky, a neuroendocrinology researcher at Stanford University, who was not directly involved in the research but helped review the new paper. Advertisement Neuropeptide Y is associated with “hedonic eating”—consuming food strictly to experience pleasure rather than to satisfy hunger. It drives individuals to seek out high-calorie foods, especially those rich in fat. Historically, though, NPY has been overlooked in favor of flashier “feel good” chemicals such as dopamine and serotonin. © 2023 Scientific American,

Keyword: Obesity; Intelligence
Link ID: 28905 - Posted: 09.13.2023

By Ann Gibbons Go to the Democratic Republic of the Congo, and you’re unlikely to encounter chimps so plump they have trouble climbing trees or vervet monkeys so chubby they huff and puff as they swing from branch to branch. Humans are a different story. Walk down a typical U.S. street and almost half of the people you encounter are likely to have obesity. Scientists have long blamed our status as the “fattest primate” on genes that help us store fat more efficiently or diets overloaded with sugars or fat. But a new study of 40 species of nonhuman primates, ranging from tiny mouse lemurs to hulking gorillas, finds many pack on the pounds just as easily as we do, regardless of diet, habitat, or genetic differences. All they need is extra food. “Lots of primates put on too much weight, the same as humans,” says Herman Pontzer, a biological anthropologist at Duke University and author of the new study, published this week in the Philosophical Transactions of the Royal Society B. “Humans are not special.” Some researchers have suggested our species is prone to obesity because our ancestors evolved to be incredibly efficient at storing calories. The adaptation would have helped our ancient relatives, who often faced famine after the transition to agriculture, get through lean times. This selection pressure for so-called thrifty genes set us apart from other primates, the thinking goes. But other primates can get fat. Kanzi, the first ape to show he understands spoken English, was triple the average weight of his bonobo species after years of being rewarded with bananas, peanuts, and other treats during research; scientists eventually put him on a diet. And then there was Uncle Fatty, an obese macaque who lived on the streets of Bangkok where tourists fed him milkshakes, noodles, and other junk food. He weighed an astonishing 15 kilograms—three times more than the average macaque—before he went to the monkey equivalent of a fat farm. © 2023 American Association for the Advancement of Science.

Keyword: Obesity; Evolution
Link ID: 28902 - Posted: 09.10.2023

Linda Geddes I’ve made a cup of coffee, written my to-do list and now I’m wiring up my ear to a device that will send an electrical message to my brainstem. If the testimonials are to believed, incorporating this stimulating habit into my daily routine could help to reduce stress and anxiety, curb inflammation and digestive issues, and perhaps improve my sleep and concentration by tapping into the “electrical superhighway” that is the vagus nerve. From plunging your face into icy water, to piercing the small flap of cartilage in front of your ear, the internet is awash with tips for hacking this system that carries signals between the brain and chest and abdominal organs. Manufacturers and retailers are also increasingly cashing in on this trend, with Amazon alone offering hundreds of vagus nerve products, ranging from books and vibrating pendants to electrical stimulators similar to the one I’ve been testing. Meanwhile, scientific interest in vagus nerve stimulation is exploding, with studies investigating it as a potential treatment for everything from obesity to depression, arthritis and Covid-related fatigue. So, what exactly is the vagus nerve, and is all this hype warranted? The vagus nerve is, in fact, a pair of nerves that serve as a two-way communication channel between the brain and the heart, lungs and abdominal organs, plus structures such as the oesophagus and voice box, helping to control involuntary processes, including breathing, heart rate, digestion and immune responses. They are also an important part of the parasympathetic nervous system, which governs the “rest and digest” processes, and relaxes the body after periods of stress or danger that activate our sympathetic “fight or flight” responses. In the late 19th century, scientists observed that compressing the main artery in the neck – alongside which the vagus nerves run – could help to prevent or treat epilepsy. This idea was resurrected in the 1980s, when the first electrical stimulators were implanted into the necks of epilepsy patients, helping to calm down the irregular electrical brain activity that triggers seizures. © 2023 Guardian News & Media Limited

Keyword: Depression; Obesity
Link ID: 28886 - Posted: 08.26.2023

By Gina Kolata Every so often a drug comes along that has the potential to change the world. Medical specialists say the latest to offer that possibility are the new drugs that treat obesity — Ozempic, Wegovy, Mounjaro and more that may soon be coming onto the market. It’s early, but nothing like these drugs has existed before. “Game changers,” said Jonathan Engel, a historian of medicine and health care policy at Baruch College in New York. Obesity affects nearly 42 percent of American adults, and yet, Dr. Engel said, “we have been powerless.” Research into potential medical treatments for the condition led to failures. Drug companies lost interest, with many executives thinking — like most doctors and members of the public — that obesity was a moral failing and not a chronic disease. While other drugs discovered in recent decades for diseases like cancer, heart disease and Alzheimer’s were found through a logical process that led to clear targets for drug designers, the path that led to the obesity drugs was not like that. In fact, much about the drugs remains shrouded in mystery. Researchers discovered by accident that exposing the brain to a natural hormone at levels never seen in nature elicited weight loss. They really don’t know why, or if the drugs may have any long-term side effects. “Everyone would like to say there must be some logical explanation or order in this that would allow predictions about what will work,” said Dr. David D’Alessio, chief of endocrinology at Duke, who consults for Eli Lilly among others. “So far there is not.” Although the drugs seem safe, obesity medicine specialists call for caution because — like drugs for high cholesterol levels or high blood pressure — the obesity drugs must be taken indefinitely or patients will regain the weight they lost. Dr. Susan Yanovski, a co-director of the office of obesity research at the National Institute of Diabetes and Digestive and Kidney Diseases, warned that patients would have to be monitored for rare but serious side effects, especially as scientists still don’t know why the drugs work. But, she added, obesity itself is associated with a long list of grave medical problems, including diabetes, liver disease, heart disease, cancers, sleep apnea and joint pain. “You have to keep in mind the serious diseases and increased mortality that people with obesity suffer from,” she said. © 2023 The New York Times Company

Keyword: Obesity
Link ID: 28875 - Posted: 08.19.2023

By Laurie McGinley and David Ovalle The weight-loss drug Wegovy reduced the risk of strokes, heart attacks and other cardiovascular problems by 20 percent among overweight people with a history of heart disease, its manufacturer said Tuesday, results that could increase demand and bolster the case for insurance coverage for the medication. The better-than-expected result was announced by Danish pharmaceutical giant Novo Nordisk in a news release. Experts said the results of the trial, called Select, demonstrate that a new crop of drugs commonly used for weight loss, such as Wegovy, can provide important health benefits, not just cosmetic ones. Obesity should be treated as a serious illness given its connection to other problems such as heart disease, specialists said. Still, private insurers have been slow to cover Wegovy, and Medicare is barred from paying for weight-loss medications. With Wegovy costing more than $1,300 a month, the lack of insurance coverage has put the drug out of reach for many people. The study is important because it could shift perceptions of Wegovy and similar drugs, said Andres J. Acosta, an assistant professor of medicine and a consultant in gastroenterology and hepatology at the Mayo Clinic. Previously, the medications were highlighted for their cosmetic results. “It’s a new era,” Acosta said. “It matters because if you lose weight, your risk of dying is reduced.” The data from the highly anticipated trial have not been published. The results released Tuesday were top-line findings, and the company said it would release detailed results at a conference later this year. Steven Nissen, a Cleveland Clinic cardiologist, noted that while Tuesday’s announcement is promising, he wants to see the full results. “We have to be cautious until we actually see the peer-reviewed publication,” said Nissen, who is leading a similar trial involving Eli Lilly’s Mounjaro, a diabetes drug commonly used for weight loss.

Keyword: Obesity
Link ID: 28868 - Posted: 08.09.2023

By Gina Kolata A national survey released on Friday by KFF, a nonprofit organization focused on health policy, has found that Americans long for safe and effective drugs for weight loss. But the more they learn about new drugs like Wegovy that are transforming obesity treatment, the more their enthusiasm fades. The survey found that 59 percent of people who were trying to lose weight said they were interested in taking a safe and effective drug. But only 23 percent remained interested when asked if they would take such a drug if it had to be injected. And just 16 percent were still interested if their insurance would not pay for the drug. The list price of the drugs is about $1,300 a month. When they heard they would regain their lost weight it they stopped taking the drug, interest declined to 14 percent. “People always want that magic pill,” said Ashley Kirzinger, director of survey methodology at KFF. “There is no magic.” The survey was conducted in July online and by telephone with a representative sample of 1,327 U.S. adults. That’s the median weight loss experienced by people who take Wegovy, a drug from Novo Nordisk. The new drugs are the first truly effective obesity medicines. They act by stemming people’s appetites and cravings for food. Many patients started by taking Ozempic, a diabetes drug also by Novo Nordisk that led to weight loss as a side effect. But many more patients are asking for Wegovy, which is approved for obesity. Mounjaro, made by Eli Lilly and approved for treating diabetes, is expected to be approved soon for obesity. People taking it lose a median of 20 percent of their body weight. Obesity is a chronic disease that can result in diabetes and other conditions like high blood pressure, heart disease, sleep apnea and joint problems. But it was so difficult to treat obesity that many doctors and patients had all but given up. © 2023 The New York Times Company

Keyword: Obesity
Link ID: 28865 - Posted: 08.05.2023

McKenzie Prillaman It’s rare to find a product so successful that its makers stop advertising it. But that’s what happened to the weight-loss drug Wegovy in May. In the United States, where prescription drugs can be advertised, developer Novo Nordisk pulled its television adverts because it couldn’t keep up with demand. The injectable medication, called semaglutide, works by imitating a hormone that curbs appetite and was approved as an obesity treatment by the US Food and Drug Administration (FDA) in 2021. In a study, participants who took semaglutide for over a year lost more than twice as much body weight on average — almost 16% — as did people taking an older weight-loss drug that mimics the same hormone1. Semaglutide’s approval for treatment of weight loss came four years after the drug was approved for type 2 diabetes under the trade name Ozempic, also made by Novo Nordisk, based in Bagsværd, Denmark. Demand for Ozempic has skyrocketed as physicians prescribe it for weight loss outside its approved use. Now, even more-potent medications for obesity are on the way. The drug tirzepatide, which is FDA-approved for type 2 diabetes under the name Mounjaro and made by Eli Lilly in Indianapolis, Indiana, imitates two hunger-related hormones. And the company’s drug retatrutide, which mimics three hormones, showed promising results for weight loss in its mid-stage clinical trial, announced at a conference in June. Neither of these newcomers has been approved for obesity. But treating the condition is more urgent than ever. Obesity rates have tripled in the past 50 years, and carrying significant extra weight often brings a heightened risk of other health complications, including type 2 diabetes, heart disease and some cancers. It can also impede quality of life in other ways, such as limiting a person’s range of movement or resulting in feelings of shame because of weight stigma. With this wave of drugs comes a fresh set of questions for researchers. “We are currently in such a dynamic phase of these transformative developments,” says physician-scientist Matthias Tschöp, chief executive of Helmholtz Munich, a research centre in Germany. “We’re still overwhelmed with curiosity.” © 2023 Springer Nature Limited

Keyword: Obesity
Link ID: 28862 - Posted: 08.02.2023

Will Stone Intermittent fasting has taken off in popularity in recent years as an alternative to more traditional weight loss advice, including counting calories, which can be cumbersome and hard to sustain for some people. Intermittent fasting can take different forms. One approach — called time-restricted eating — limits when people eat to a specific window of time, often around six to eight hours. Some research suggests this can be successful for weight loss in the short term because people end up eating less, but it has been less clear how well it works over a longer stretch of time. A study published Monday may have an answer. "We really wanted to see if people can lose weight with this over a year. Can they maintain the weight loss?" says Krista Varady, a professor of nutrition at the University of Illinois Chicago, who has studied intermittent fasting for the past two decades and led the new study. Varady's research finds that intermittent fasting can indeed help people lose weight and keep it off over the course of a year, with effects similar to tracking calories. The results of the clinical trial were published in the Annals of Internal Medicine. Sponsor Message The amount of weight loss wasn't dramatic — equivalent to about 5% of body weight — but the findings are encouraging to researchers in the field, in part because they underscore that people could keep this habit up over a long stretch of time. "That is pretty exciting," says Courtney Peterson, a professor of nutrition at the University of Alabama at Birmingham, who wasn't involved in the research. "This study has the most compelling results suggesting that people can stick with it, that it's not a fad diet in the sense that people can do it for three months and they fall off the wagon for a year." © 2023 npr

Keyword: Obesity
Link ID: 28833 - Posted: 06.28.2023

By Dani Blum Until she started taking the weight loss drug Wegovy, Staci Klemmer’s days revolved around food. When she woke up, she plotted out what she would eat; as soon as she had lunch, she thought about dinner. After leaving work as a high school teacher in Bucks County, Pa., she would often drive to Taco Bell or McDonald’s to quell what she called a “24/7 chatter” in the back of her mind. Even when she was full, she wanted to eat. Almost immediately after Ms. Klemmer’s first dose of medication in February, she was hit with side effects: acid reflux, constipation, queasiness, fatigue. But, she said, it was like a switch flipped in her brain — the “food noise” went silent. “I don’t think about tacos all the time anymore,” Ms. Klemmer, 57, said. “I don’t have cravings anymore. At all. It’s the weirdest thing.” Dr. Andrew Kraftson, a clinical associate professor at Michigan Medicine, said that over his 13 years as an obesity medicine specialist, people he treated would often say they couldn’t stop thinking about food. So when he started prescribing Wegovy and Ozempic, a diabetes medication that contains the same compound, and patients began to use the term food noise, saying it had disappeared, he knew exactly what they meant. As interest has intensified around Ozempic and other injectable diabetes medications like Mounjaro, which works in similar ways, that term has gained traction. Videos related to the subject “food noise explained” have been viewed 1.8 billion times on TikTok. And some of the people who have managed to get their hands on these medications — despite persistent shortages and list prices that can near or surpass a thousand dollars — have shared stories on social media about their experiences. When food noise fades Wendy Gantt, 56, said she first heard the term food noise on TikTok, where she had also learned about Mounjaro. She found a telehealth platform and received a prescription within a few hours. She can remember the first day she started taking it last summer. “It was like a sense of freedom from that loop of, ‘What am I going to eat? I’m never full; there’s not enough. What can I snack on?’” she said. “It’s like someone took an eraser to it.” © 2023 The New York Times Company

Keyword: Obesity
Link ID: 28830 - Posted: 06.21.2023

By Gina Kolata Eileen Isotalo was always able to lose weight, but always gained it back. Now 66, her first diet was with Weight Watchers at age 14. She went on to try one diet after another and bought so many books on weight loss that she thinks she has more than the public library. In desperation, she finally went to a weight management clinic at the University of Michigan. She had sleep apnea and aching knees, but could not curb her appetite. “It’s just this drive to eat,” said Ms. Isoltalo, a retired interior design coordinator. “It’s almost like this panic feeling when you start craving food.” “My mental shame was profound,” she said. Now, though, since she started taking Wegovy, one of a new class of drugs for obesity that was prescribed by her doctor at the clinic, those cravings are gone. She has lost 50 pounds and jettisoned the dark clothes she wore to hide her body. Her obesity-related medical problems have vanished along with much of the stigma that caused her to retreat from family and friends. But like others at the clinic, she still struggles with the fear others will judge her for receiving injections to treat her obesity rather than finding the willpower to lose weight and keep it off. Yet the drug, she said, “changed my life.” Wegovy and drugs like it make this “a very exciting time in the field,” said Dr. Susan Yanovski, co-director of the office of obesity research at the National Institute of Diabetes and Digestive and Kidney Diseases. About 100 million Americans, or 42 percent of the adult population, have obesity, according to the Centers for Disease Control and Prevention. For the first time, people with obesity, who faced a lifetime of medical jeopardy, can escape the ruthless trap of fruitless dieting and see their obesity-related health problems mitigated, along with the weight loss. But there is still the taint. © 2023 The New York Times Company

Keyword: Obesity
Link ID: 28821 - Posted: 06.14.2023

Ian Sample Science editor The sight of their dead comrades is enough to drive fruit flies to an early grave, according to researchers, who suspect the creatures keel over after developing the fly equivalent of depression. For a species that spends much of its life feasting on decayed matter, the insects appear to be particularly sensitive to their own dead. Witnessing an abundance of fruit fly carcasses speeds up the insects’ ageing process, scientists found, cutting their lives short by nearly 30%. While the researchers are cautious about extrapolating from 3mm-long flies to rather larger humans that can live 400 times longer, they speculate that the insights might prove useful for people who are routinely surrounded by death, such as combat troops and healthcare workers. “Could motivational therapy or pharmacologic intervention in reward systems, much like what is done for addiction, slow ageing?” the authors ask in Plos Biology. The possibility could be tested in humans today, they added, using drugs that are already approved. Researchers led by Christi Gendron and Scott Pletcher at the University of Michigan raised fruit flies in small containers filled with food. While some of the containers held only living flies and tasty nutrients, others were dotted with freshly dead fruit flies as well, to see what impact they had on the feeding insects. When fruit flies were raised among dead ones, they tended to die several weeks earlier than those raised without being surrounded by carcasses. Those exposed to death appeared to age faster, losing stored fat and becoming less resilient to starvation. © 2023 Guardian News & Media Limited

Keyword: Stress
Link ID: 28819 - Posted: 06.14.2023

By Amber Dance Maybe it starts with a low-energy feeling, or maybe you’re getting a little cranky. You might have a headache or difficulty concentrating. Your brain is sending you a message: You’re hungry. Find food. Studies in mice have pinpointed a cluster of cells called AgRP neurons near the underside of the brain that may create this unpleasant hungry, even “hangry,” feeling. They sit near the brain’s blood supply, giving them access to hormones arriving from the stomach and fat tissue that indicate energy levels. When energy is low, they act on a variety of other brain areas to promote feeding. By eavesdropping on AgRP neurons in mice, scientists have begun to untangle how these cells switch on and encourage animals to seek food when they’re low on nutrients, and how they sense food landing in the gut to turn back off. Researchers have also found that the activity of AgRP neurons goes awry in mice with symptoms akin to those of anorexia, and that activating these neurons can help to restore normal eating patterns in those animals. Understanding and manipulating AgRP neurons might lead to new treatments for both anorexia and overeating. “If we could control this hangry feeling, we might be better able to control our diets,” says Amber Alhadeff, a neuroscientist at the Monell Chemical Senses Center in Philadelphia. AgRP neurons appear to be key players in appetite: Deactivating them in adult mice causes the animals to stop eating — they may even die of starvation. Conversely, if researchers activate the neurons, mice hop into their food dishes and gorge themselves. © 2023 Annual Reviews

Keyword: Obesity
Link ID: 28799 - Posted: 05.27.2023

By Leo Sands Just under half of obese adolescents administered the latest in a new generation of recently approved weight-loss drugs were no longer considered to be clinically obese by the end of a 16-month trial, a study found. The findings support a small but growing body of evidence that the drug semaglutide, which goes by the brand names of Ozempic and Wegovy, can be an effective treatment option for chronic weight management for a range of ages. Obesity rates for children and adolescents are now alarmingly high in many countries, with such significant implications for young lives that the World Health Organization considers childhood obesity “one of the most serious public health challenges of the 21st century.” The authors of the new peer-reviewed study, published Wednesday in the journal Obesity, found that semaglutide was “highly effective” in reducing body mass index among teens. The weights of 134 clinically obese adolescents were monitored for 68 weeks, with participants given a 2.4 milligram injection of semaglutide weekly. By the end of the study, 45 percent of the group recorded a drop in BMI to below the clinical threshold for obesity. Just 12 percent of participants in a separate group who received a placebo were no longer considered to be obese at the end of the trial. Both groups also got lifestyle counseling and had a daily goal of 60 minutes of moderate- to high-intensity physical activity.

Keyword: Obesity
Link ID: 28784 - Posted: 05.18.2023

By Erin Blakemore Newly published research suggests that the sons of women with polycystic ovary syndrome (PCOS) are up to twice as likely to develop obesity as their peers. The study in Cell Reports Medicine used data from cohort research following 467,275 male infants born in Sweden between July 2006 and December 2015. Of those, 9,828 were born to a mother with PCOS — and 147 of those boys were eventually diagnosed with obesity. About 2 in 100 Swedish boys who were born to mothers with PCOS became obese during childhood, compared with about 1 in 100 for boys whose mothers did not have PCOS. The risk was higher among the sons of women who had PCOS and a body mass index (BMI) greater than 25 and highest among the sons of women who both had PCOS and did not take metformin during pregnancy. Researchers followed up the analysis with an RNA sequencing study that found higher cholesterol in sons of Chilean women with PCOS than controls. In another analysis, researchers fed a group of mice a fatty, sugary diet and exposed them to high levels of dihydrotestosterone, a hormone that mimics that of pregnant women with PCOS. Their sons were born with metabolic problems that persisted into adulthood, even when they ate a healthy diet throughout their lives. “We could see that these male mice had more fat tissue, larger fat cells, and a disordered basal metabolism, despite eating a healthy diet,” says Elisabet Stener-Victorin, a reproductive endocrinology and metabolism investigator at the Karolinska Institute in Sweden and the study’s lead author, in a news release.

Keyword: Obesity; Hormones & Behavior
Link ID: 28776 - Posted: 05.10.2023

By Tim Vernimmen This story starts in an unusual place for an article about human nutrition: a cramped, humid and hot room somewhere in the Zoology building of the University of Oxford in England, filled with a couple hundred migratory locusts, each in its own plastic box. It was there, in the late 1980s, that entomologists Stephen Simpson and David Raubenheimer began working together on a curious job: rearing these notoriously voracious insects, to try and find out whether they were picky eaters. Every day, Simpson and Raubenheimer would weigh each locust and feed it precise amounts of powdered foods containing varying proportions of proteins and carbohydrates. To their surprise, the young scientists found that whatever food the insects were fed, they ended up eating almost exactly the same amount of protein. In fact, locusts feeding on food that was low in protein ate so much extra in order to reach their protein target that they ended up overweight — not chubby on the outside, since their exoskeleton doesn’t allow for bulges, but chock-full of fat on the inside. Inevitably, this made Simpson and Raubenheimer wonder whether something similar might be causing the documented rise in obesity among humans. Many studies had reported that even as our consumption of fats and carbohydrates increased, our consumption of protein did not. Might it be that, like locusts, we are tricked into overeating, in our case by the irresistible, low-protein, ultraprocessed foods on the shelves of the stores where we do most of our foraging? That’s what Raubenheimer and Simpson, both now at the University of Sydney, argue in their recent book “Eat Like the Animals” and in an overview in the Annual Review of Nutrition. © 2023 Annual Reviews

Keyword: Obesity; Attention
Link ID: 28764 - Posted: 05.03.2023

By Darius Tahir & Hannah Norman, KHN Suzette Zuena is her own best advertisement for weight loss. Zuena, the “founder/visionary” of LH Spa & Rejuvenation in Livingston and Madison, New Jersey, has dropped 30 pounds. Her husband has lost 42 pounds. “We go out a lot,” Zuena said of the pair’s social routine. “People saw us basically shrinking.” They would ask how the couple did it. Her response: point people to her spa and a relatively new type of medication — GLP-1 agonists, a class of drug that’s become a weight loss phenomenon. But she’s not just spreading her message in person. She’s also doing it on Instagram. And she’s not alone. A chorus of voices is singing these drugs’ praises. Last summer, investment bank Morgan Stanley found mentions of one of these drugs on TikTok had tripled. People are streaming into doctors’ office to inquire about what they’ve heard are miracle drugs. What these patients have heard, doctors said, is nonstop hype, even misinformation, from social media influencers. “I’ll catch people asking for the skinny pen, the weight loss shot, or Ozempic,” said Priya Jaisinghani, an endocrinologist and clinical assistant professor at New York University’s Grossman School of Medicine. Competition to claim a market that could be worth $100 billion a year for drugmakers alone has triggered a wave of advertising that has provoked the concern of regulators and doctors worldwide. But their tools for curbing the ads that go too far are limited — especially when it comes to social media. Regulatory systems are most interested in pharma’s claims, not necessarily those of doctors or their enthused patients.

Keyword: Obesity
Link ID: 28754 - Posted: 04.26.2023

by Sarah DeWeerdt Many papers about autism-linked genes note that the genes are expressed throughout both the central and the peripheral nervous systems. The proportion of such prolific genes may be as high as two-thirds, according to one 2020 analysis. Yet few studies delve into what those genes are actually doing outside the brain. That’s starting to change. Although autism is typically thought of as a brain condition, a critical mass of researchers has started to investigate how the condition alters neurons elsewhere in the body. Their work — part of a broader trend in neuroscience to look beyond the brain — hints that the role of the peripheral nervous system in autism is, well, anything but peripheral: Neuronal alterations outside the brain may help to explain a host of the condition’s characteristic traits. Much of the research so far focuses on touch and the workings of the gut, but there is increasing interest in other sensory and motor neurons, as well as the autonomic nervous system, which orchestrates basic body functions such as heartbeat, blood pressure, breathing and digestion. It’s difficult to pinpoint whether some autism traits arise in the peripheral nervous system or the central nervous system; in many cases, complex feedback loops link the two. “Your nervous system doesn’t know that we’ve divided it that way,” says Carissa Cascio, associate professor of psychiatry and behavioral sciences at Vanderbilt University in Nashville, Tennessee. But at least some peripheral changes may offer novel treatment targets. And drugs that act in the peripheral nervous system could also prove more effective and have fewer side effects than brain-based therapies, says Julia Dallman, associate professor of biology at the University of Miami in Coral Gables, Florida. © 2023 Simons Foundation

Keyword: Autism
Link ID: 28739 - Posted: 04.15.2023

Heidi Ledford Under the right circumstances, even moderately hungry mice prefer to socialize with the opposite sex than to eat, researchers have found1. In research published on 23 February in Cell Metabolism, scientists treated male mice with a technique that mimics the effects of leptin, a hormone that acts on the brain to suppress appetite. Treated mice were more likely to approach female mice than their food bowls — even if the test rodents had been deprived of food for almost an entire day. The findings reveal a surprising role for leptin in social behaviour. They are also a step towards understanding how animals prioritize different behavioural options in response to ongoing needs — an enduring question in neuroscience, says Gina Leinninger, who studies the neural regulation of feeding at Michigan State University in East Lansing. The paper “addresses a huge gap in the field”, she says. “When you no longer need to eat urgently, it should free you up to do other things.” The new work, Leinninger says, illuminates how the brain juggles these various demands. Food versus friends Neuroscientists Anne Petzold and Tatiana Korotkova at the University of Cologne in Germany, and their colleagues, sought to understand how such decision-making is affected by leptin, which activates a subset of cells in the brain and promotes a feeling of fullness. The researchers injected male mice with leptin and saw that it suppressed feeding, as expected — but also promoted interactions with female mice. The team examined neurons in the brain’s ‘hunger center’, the lateral hypothalamus, that are activated by leptin. The authors’ experiments showed that neurons that can sense leptin were activated when mice interacted with members of the opposite sex. Artificially activating those neurons using a technique called optogenetics raised the likelihood that a mouse would approach a member of the opposite sex. Both results suggest that leptin plays a part in promoting social behaviour. © 2023 Springer Nature Limited

Keyword: Obesity; Sexual Behavior
Link ID: 28682 - Posted: 02.25.2023

By Kelsey Herbers The comments started the day I became engaged in December 2018: “You’re going to be such a beautiful bride.” “I can’t wait to see you in your dress.” “Everything is going to be perfect.” Before my fiancé and I even booked our wedding date, originally April 25, 2020, or saved a color scheme on Pinterest, I felt an intensifying pressure to live up to the high expectations that I thought my friends and family already had for my wedding day. I was determined to meet those expectations. But the innocent, wedding-driven diet that commenced shortly after my engagement ultimately spiraled into a full-fledged eating disorder. I was shocked by how quickly I fell ill and how deep that illness was. There was nothing about my journey, however, that surprised Robyn L. Goldberg, a registered dietitian and author of “The Eating Disorder Trap.” “The research shows one out of three people who diet develop an eating disorder — it’s very, very common,” said Ms. Goldberg, who has worked in private practice for the last 25 years with clients who have eating disorders, including many future brides. Some have ended up in residential treatment, she said. “You get so consumed that to pull yourself out of that dark hole seems impossible.” In the early days of wedding planning, my lifestyle changes were subtle. I bought an elliptical machine, took note of my calorie intake and found healthier meal options. But when the pandemic hit and kept me at home with my gym equipment, measuring cups and extra time on my hands, the opportunities to try new weight loss methods and obsess over my progress grew. It also forced us to postpone our wedding date. In just a few months, I was severely limiting my calorie intake, weighing myself several times a day and adhering to strict, self-proclaimed exercise rules. This included 45 minutes of running on a treadmill and 120 minutes of walking (180 minutes on weekends) daily. Before my engagement, I had never heard of intermittent fasting, but it didn’t take long for me to master it. These behavioral changes happened so gradually that I didn’t even recognize something was wrong until nearly two years later. By then I had lost 50 pounds, though initially I had wanted to shed only 25. © 2023 The New York Times Company

Keyword: Anorexia & Bulimia
Link ID: 28650 - Posted: 02.01.2023