Links for Keyword: Obesity

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Susan Gaidos CHICAGO — Eating a high-fat diet as a youngster can affect learning and memory during adulthood, studies have shown. But new findings suggest such diets may not have long-lasting effects. Rats fed a high-fat diet for nearly a year recovered their ability to navigate their surroundings. University of Texas at Dallas neuroscientist Erica Underwood tested spatial memory for rats fed a high-fat diet for either 12 weeks or 52 weeks, immediately after weaning. After rats placed in a chamber-filled box containing Lego-like toys became familiar with the box, the researchers moved the toys to new chambers. Later, when placed in the box, rats who ate high-fat foods for 12 weeks appeared confused and had difficulty finding the toys. But rats that ate high-fat foods for nearly a year performed as well as those fed a normal diet. Underwood repeated the experiment, posing additional spatial memory tests to new groups of rats. The findings were the same: Over the long-term, rats on high-fat diets recovered their ability to learn and remember. Studies of brain cells revealed that rats on the long-term high-fat diet showed reduced excitability in nerve cells from the hippocampus, the same detrimental effects seen in rats on the short-term high-fat diet. “The physiology that should create a dumber animal is there, but not the behavior,” said Lucien Thompson of UT Dallas, who oversaw the study. Underwood and Thompson speculate that some other part of the brain may be compensating for this reduction in neural response. © Society for Science & the Public 2000 - 2015.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 13: Memory, Learning, and Development
Link ID: 21533 - Posted: 10.21.2015

Peter Andrey Smith Nearly a year has passed since Rebecca Knickmeyer first met the participants in her latest study on brain development. Knickmeyer, a neuroscientist at the University of North Carolina School of Medicine in Chapel Hill, expects to see how 30 newborns have grown into crawling, inquisitive one-year-olds, using a battery of behavioural and temperament tests. In one test, a child's mother might disappear from the testing suite and then reappear with a stranger. Another ratchets up the weirdness with some Halloween masks. Then, if all goes well, the kids should nap peacefully as a noisy magnetic resonance imaging machine scans their brains. “We try to be prepared for everything,” Knickmeyer says. “We know exactly what to do if kids make a break for the door.” Knickmeyer is excited to see something else from the children — their faecal microbiota, the array of bacteria, viruses and other microbes that inhabit their guts. Her project (affectionately known as 'the poop study') is part of a small but growing effort by neuroscientists to see whether the microbes that colonize the gut in infancy can alter brain development. The project comes at a crucial juncture. A growing body of data, mostly from animals raised in sterile, germ-free conditions, shows that microbes in the gut influence behaviour and can alter brain physiology and neurochemistry. © 2015 Nature Publishing Group

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 13: Memory, Learning, and Development
Link ID: 21521 - Posted: 10.16.2015

By Nicholas Bakalar There may be a link between later bedtimes and weight gain, new research suggests. Researchers studied 3,342 adolescents starting in 1996, following them through 2009. At three points over the years, all reported their normal bedtimes, as well as information on fast food consumption, exercise and television time. The scientists calculated body mass index at each interview. After controlling for age, sex, race, ethnicity and socioeconomic status, the researchers found that each hour later bedtime during the school or workweek was associated with about a two-point increase in B.M.I. The effect was apparent even among people who got a full eight hours of sleep, and neither TV time nor exercise contributed to the effect. But fast food consumption did. The study, in the October issue of Sleep, raises questions, said the lead author, Lauren D. Asarnow, a graduate student at the University of California, Berkeley. “First, what is driving this relationship?” she said. “Is it metabolic changes that happen when you stay up late? And second, if we change sleep patterns, can we change eating behavior and the course of weight change?” The scientists acknowledge that their study had limitations. Their sleep data depended on self-reports, and they did not have complete diet information. Also, they had no data on waist circumference, which, unlike B.M.I., can help distinguish between lean muscle and abdominal fat. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 10: Biological Rhythms and Sleep
Link ID: 21483 - Posted: 10.07.2015

By Kelly Servick Children born to obese mothers arrive already predisposed to obesity and other health problems themselves. Exactly what happens in the uterus to transmit this risk still isn’t clear, but a new study on mice points to the placenta as a key actor. The study shows that a hormone acting on the placenta can protect the offspring of obese mice from being born overweight. It suggests ways to break the cycle of obesity in humans—although other researchers caution there's a long way to go. Researchers discovered decades ago that conditions in the uterus can “program” a fetus to be more susceptible to certain health problems. People conceived during the 1944 famine in the Netherlands, for example, suffered higher rates of cardiovascular disease, diabetes, cancer, and other problems later in life. Recent animal studies suggest that malnourishment in the womb changes the expression of DNA in ways that can be passed down for generations. But researchers are now increasingly concerned with the opposite problem. Obese women tend to give birth to larger babies with more body fat, and these children are more likely to develop metabolic syndrome—the cluster of conditions including obesity and high blood sugar that can lead to diabetes and heart disease. To probe the roots of fetal “overgrowth,” developmental biologists at the University of Colorado, Denver, looked to the placenta—the whoopee cushion–shaped organ wedged between the fetus and the wall of the uterus, where branching arteries from the umbilical cord take up oxygen and nutrients from the mother’s blood vessels. The placenta “has always been viewed as a passive organ—whatever happens to the mother is translated toward the fetus,” says lead author Irving Aye, now at the University of Cambridge in the United Kingdom. However, recent research has shown that the placenta is less an indiscriminate drainpipe than a subtle gatekeeper. © 2015 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 13: Memory, Learning, and Development
Link ID: 21456 - Posted: 09.29.2015

by Bethany Brookshire Last weekend, I ran the Navy-Air Force half-marathon. After pounding pavement for an hour or so, my legs began to feel light. Slightly numb. I felt fantastic. I had to remind myself to run, not to stop and dance, and that singing along to my candy-pop workout music — even at mile 10 — is not socially acceptable. It’s the hope of this euphoria — this runner’s high — that keeps me running. We’re not totally sure what’s responsible for this incredible high. Some studies call out our body’s endorphins. Others point to cannabinoids — chemicals related to the active compound in marijuana. A new study suggests that the appetite hormone leptin may play a role in getting us going. And from an evolutionary perspective, it makes good sense. When our dinner might make a quick getaway, it’s important to link our drive to run with our need to feed. But it’s probably not the whole story. Like many other neurobiological events, the exact recipe for runner’s high is complex and hazy. It takes a whole suite of chemicals to help us get started and to make sure we want to go the distance. Those who get runner’s high know it when they feel it. But a clinical definition is a little more slippery. “I remember someone saying the runner’s high was the moment when the body was disconnected from the brain,” says Francis Chaouloff, who studies running and motivation in mice at the French Institute of Health and Medical Research in Bordeaux. This sense of extreme euphoria, he says, is generally limited to people running or exercising for long periods of time, over many miles or hours. © Society for Science & the Public 2000 - 2015.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 21452 - Posted: 09.28.2015

By Sarah C. P. Williams When the human body needs extra energy, the brain tells fat cells to release their stores. Now, for the first time, researchers have visualized the nerves that carry those messages from brain to fat tissue. The activation of these nerves in mice, they found, helps the rodents lose weight—an observation that could lead to new slimming treatments for obese people. “The methods used here are really novel and exciting,” says neuroendocrinologist Heike Muenzberg-Gruening of Louisiana State University’s Pennington Biomedical Research Center in Baton Rouge, who was not involved in the new study. “Their work has implications for obesity research and also for studying these nerves in other tissues.” Diagrams of the chatter between the brain and fat tissues have long included two-way arrows: Fat cells produce the hormone leptin, which travels to the brain to lower appetite and boost metabolism. In turn, the brain sends signals to the fat cells when it’s time to break down their deposits of fatty molecules, such as lipids, into energy. Researchers hypothesized that there must be a set of nerve cells that hook up to traditional fat tissue to carry these messages, but they’d never been able to indisputably see or characterize them. Now they have. Thanks to two forms of microscopy, neurobiologist Ana Domingos, of the Instituto Gulbenkian de Ciência in Oeiras, Portugal, produced images showing bundles of nerves clearly enveloping fat cells in mice. She and her colleagues went on to show, using various stains, that the nerves were a type belonging to the sympathetic nervous system that stretches outward from the spinal cord and keeps the body’s systems in balance. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 11: Emotions, Aggression, and Stress
Link ID: 21448 - Posted: 09.26.2015

By Sarah C. P. Williams Immune cells are usually described as soldiers fighting invading viruses and bacteria. But they may also be waging another battle: the war against fat. When mice lack a specific type of immune cell, researchers have discovered, they become obese and show signs of high blood pressure, high cholesterol, and diabetes. The findings have yet to be replicated in humans, but they are already helping scientists understand the triggers of metabolic syndrome, a cluster of conditions associated with obesity. The new study “definitely moves the field forward,” says immunologist Vishwa Deep Dixit of the Yale School of Medicine, who was not involved in the work. “The data seem really solid.” Scientists already know that there is a correlation between inflammation—a heightened immune response—and obesity. But because fat cells themselves can produce inflammatory molecules, distinguishing whether the inflammation causes weight gain or is just a side effect has been tricky. When he stumbled on this new cellular link between obesity and the immune system, immunologist Yair Reisner of the Weizmann Institute of Science in Rehovot, Israel, was studying something completely different: autoimmune diseases. An immune molecule called perforin had already been shown to kill diseased cells by boring a hole in their outer membrane. Reisner’s group suspected that dendritic cells containing perforin might also be destroying the body’s own cells in some autoimmune diseases. To test the idea, Reisner and his colleagues engineered mice to lack perforin-wielding dendritic cells, and then waited to see whether they developed any autoimmune conditions. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 11: Emotions, Aggression, and Stress
Link ID: 21415 - Posted: 09.16.2015

Eating two and a half times more than you should will leave you overweight and prone to type 2 diabetes, although no one is entirely sure why. Now a team that fed volunteers a whopping 6000 calories a day have found some clues. Obesity is only one problem caused by eating too much. An overly large food intake can also increase a person’s risk of diabetes, heart disease and some cancers, but no one is sure why this should be the case. Resistance to the hormone insulin seems to play a role. When a healthy person eats a meal, their blood glucose levels rise, and the body responds by making insulin. This hormone prompts the body to store un-needed glucose, but people who develop insulin resistance are not able to absorb excess glucose in the same way. This means that, after eating, their blood glucose levels remain high, and over time, this can damage the kidneys, nervous system and heart, for example. Guenther Boden and Salim Merali at Temple University, Philadelphia, and their team set out to investigate how overeating might lead to insulin resistance. They fed six healthy male volunteers 6000 calories’ worth of food every day for a week – around two and a half times what they should have been eating. “It was a regular, American diet, composed of pizzas, hamburgers and that sort of thing,” says Merali. Each volunteer stayed at a hospital for the duration of the experiment, where they were bed-bound, carefully monitored and prevented from doing any sort of exercise. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21400 - Posted: 09.12.2015

By Nicholas Bakalar Being obese at age 50 may be tied to an increased risk of developing Alzheimer’s disease at a younger age. Previous studies have shown that being overweight at midlife is associated with an increased risk of developing Alzheimer’s. Now researchers have found that it also predicts occurrence at a younger age. Scientists studied 1,394 cognitively normal people, average age around 60, following them for an average of 14 years. During the study, 142 developed Alzheimer’s. After controlling for age, race, level of education and cardiovascular risk factors, they found that each unit increase in B.M.I., or body mass index, at age 50 was associated with a 6.7-month decrease in the age of onset of Alzheimer’s. The study, in Molecular Psychiatry, also found an association of higher B.M.I. with larger deposits of neurofibrillary tangles on autopsy, one of the characteristics of brain damage in Alzheimer’s disease. “Age of onset is not as well studied as risk,” said the senior author, Dr. Madhav Thambisetty, a neurologist at the National Institute on Aging. “As we try to cure Alzheimer’s disease, we also want to delay the onset of symptoms. Until we know what factors accelerate onset, we won’t be able to test any potential interventions. And that is perhaps as important as the search for treatment.” © 2015 The New York Times Company

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 13: Memory, Learning, and Development
Link ID: 21391 - Posted: 09.10.2015

by Bethany Brookshire You’ve already had a muffin. And a half. You know you’re full. But there they are, fluffy and delicious, waiting for the passersby in the office. Just thinking about them makes your mouth water. Maybe if you just slice one into quarters. I mean, that barely counts… And then we give in, our brains overriding our body’s better judgment. When I catch myself once again polishing off a whole plate of baked goods, I wish that there was something I could do, some little pill I could take that would make that last delicious bite look — and taste — a little less appealing. But the more scientists learn about the human body, the more they come to understand that there is no one set of hormones for hungry, with a separate set that kicks off your ice cream binge. Instead, our guts and their hormones are firmly entwined with our feelings of reward and motivation. That close relationship shows just how important it is to our bodies to keep us fed, and how hard it is to stop us from overeating. Researchers have long divided our feeding behavior into two distinct categories. One, the homeostatic portion, is primarily concerned with making sure we’ve got enough energy to keep going and is localized to the lateral hypothalamus in the brain. The reward-related, or “hedonic,” component is centralized in the mesolimbic dopamine system, areas of the brain usually referenced when we talk about the effects of sex, drugs and rock ’n’ roll. © Society for Science & the Public 2000 - 2015

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 21354 - Posted: 08.28.2015

Dan Charles Ah, sugar — we love the sweetness, but not the calories. For more than a century, food technologists have been on a quest for the perfect, guilt-free substitute. Ah, sugar — we love the sweetness, but not the calories. For more than a century, food technologists have been on a quest for the perfect, guilt-free substitute. Ryan Kellman/NPR There's a new candidate in the century-old quest for perfect, guiltless sweetness. I encountered it at the annual meeting of the Institute of Food Technologists, a combination of Super Bowl, Mecca, and Disneyland for the folks who put the processing in processed food. It was right in the middle of the vast exhibition hall, at the Tate & Lyle booth. This is the company that introduced the British Empire to the sugar cube, back in 1875. A century later, it invented sucralose, aka Splenda. "We have a deep understanding of sweetening," says Michael Harrison, Tate & Lyle's vice president of new product development. This year, his company launched its latest gift to your sweet tooth. It's called allulose. "This is a rare sugar. A sugar that's found in nature," Harrison explains. Chemically speaking, it's almost identical to ordinary sugar. It has the same chemical formula as fructose and glucose, but the atoms of hydrogen and oxygen are arranged slightly differently. © 2015 NPR

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 21342 - Posted: 08.26.2015

By Gretchen Vogel Researchers may have finally explained how an obesity-promoting gene variant induces some people to put on the pounds. Using state-of-the-art DNA editing tools, they have identified a genetic switch that helps govern the body’s metabolism. The switch controls whether common fat cells burn energy rather than store it as fat. The finding suggests the tantalizing prospect that doctors might someday offer a gene therapy to melt extra fat away. Along with calories and exercise, genes influence a person’s tendency to gain—and keep—extra pounds. One of the genes with the strongest link to obesity is called FTO. People with certain versions of the gene are several kilos heavier on average and significantly more likely to be obese. Despite years of study, no one had been able to figure out what the gene does in cells or how it influences weight. There was some evidence FTO helped control other genes, but it was unclear which ones. Some researchers had looked for activity of FTO in various tissues, without finding any clear signals. Melina Claussnitzer, Manolis Kellis, and their colleagues at Harvard University, Massachusetts Institute of Technology, and the Broad Institute in Cambridge, turned to data from the Roadmap Epigenomics Project, an 8-year effort that identified the chemical tags on DNA that influence the function of genes. The researchers used those epigenetic tags to look at whether FTO was turned on or off in 127 cell types. The gene seemed to be active in developing fat cells called adipocyte progenitor cells. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21326 - Posted: 08.22.2015

Tina Hesman Saey Researchers have discovered a “genetic switch” that determines whether people will burn extra calories or save them as fat. A genetic variant tightly linked to obesity causes fat-producing cells to become energy-storing white fat cells instead of energy-burning beige fat, researchers report online August 19 in the New England Journal of Medicine. Previously scientists thought that the variant, in a gene known as FTO (originally called fatso), worked in the brain to increase appetite. The new work shows that the FTO gene itself has nothing to do with obesity, says coauthor Manolis Kellis, a computational biologist at MIT and the Broad Institute. But the work may point to a new way to control body fat. In humans and many other organisms, genes are interrupted by stretches of DNA known as introns. Kellis and Melina Claussnitzer of Harvard Medical School and colleagues discovered that a genetic variant linked to increased risk of obesity affects one of the introns in the FTO gene. It does not change the protein produced from the FTO gene or change the gene’s activity. Instead, the variant doubles the activity of two genes, IRX3 and IRX5, which are involved in determining which kind of fat cells will be produced. FTO’s intron is an enhancer, a stretch of DNA needed to control activity of far-away genes, the researchers discovered. Normally, a protein called ARID5B squats on the enhancer and prevents it from dialing up activity of the fat-determining genes. In fat cells of people who have the obesity-risk variant, ARID5B can’t do its job and the IRX genes crank up production of energy-storing white fat. © Society for Science & the Public 2000 - 2015.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 13: Memory, Learning, and Development
Link ID: 21321 - Posted: 08.20.2015

By Gretchen Reynolds Sticking to a diet requires self-control and a willingness to forgo present pleasures for future benefits. Not surprisingly, almost everyone yields to temptation at least sometimes, opting for the cookie instead of the apple. Wondering why we so often override our resolve, scientists at the Laboratory for Social and Neural Systems Research at the University of Zurich recently considered the role of stress, which is linked to a variety of health problems, including weight gain. (There’s something to the rom-com cliché of the jilted lover eating ice cream directly from the carton.) But just how stress might drive us to sweets has not been altogether clear. It turns out that even mild stress may immediately alter the workings of our brains in ways that undermine willpower. For their study, published this month in Neuron, researchers recruited 51 young men who said they were trying to maintain a healthy diet and lifestyle. The men were divided into two groups, one of which served as a control, and then all were asked to skim through images of different kinds of food on a computer screen, rating them for taste and healthfulness. Next, the men in the experimental group were told to plunge a hand into a bowl of icy water for as long as they could, a test known to induce mild physiological and psychological stress. Relative to the control group, the men developed higher levels of cortisol, a stress hormone. After that, men from each group sat in a brain-scanning machine and watched pictures of paired foods flash across a screen. Generally, one of the two foods was more healthful than the other. The subjects were asked to click rapidly on which food they would choose to eat, knowing that at the end of the test they would actually be expected to eat one of these picks (chosen at random from all of their choices). © 2015 The New York Times Company

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 11: Emotions, Aggression, and Stress
Link ID: 21320 - Posted: 08.20.2015

By James Gallagher Health editor, BBC News website Fat or carbs? Scientists have shed new light on which diet might be more effective at reducing fat Cutting fat from your diet leads to more fat loss than reducing carbohydrates, a US health study shows. Scientists intensely analysed people on controlled diets by inspecting every morsel of food, minute of exercise and breath taken. Both diets, analysed by the National Institutes of Health, led to fat loss when calories were cut, but people lost more when they reduced fat intake. Experts say the most effective diet is one people can stick to. It has been argued that restricting carbs is the best way to get rid of a "spare tyre" as it alters the body's metabolism. The theory goes that fewer carbohydrates lead to lower levels of insulin, which in turn lead to fat being released from the body's stores. "All of those things do happen with carb reduction and you do lose body fat, but not as much as when you cut out the fat," said lead researchers Dr Kevin Hall, from the US-based National Institute of Diabetes and Digestive and Kidney Diseases. Cutting down on carbohydrates might not be as effective after all, the study suggests In the study, 19 obese people were initially given 2,700 calories a day. Then, over a period of two weeks they tried diets which cut their calorie intake by a third, either by reducing carbohydrates or fat. The team analysed the amount of oxygen and carbon dioxide being breathed out and the amount of nitrogen in participants' urine to calculate precisely the chemical processes taking place inside the body. The results published in Cell Metabolism showed that after six days on each diet, those reducing fat intake lost an average 463g of body fat - 80% more than those cutting down on carbs, whose average loss was 245g. © 2015 BBC.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21296 - Posted: 08.15.2015

By Dina Fine Maron Don’t stress too much about cutting calories if you want to shed pounds—focus on getting more exercise. That’s the controversial message beverage giant Coca-Cola is backing in its new campaign to curb obesity. Coke is pushing this idea via a new Coke-backed nonprofit called Global Energy Balance Network, The New York Times reported on August 9. Money from Coke, the Times reported, is also financing studies that support the notion that exercise trumps diet. But is there any merit to such a stance? Not much, says Rutgers University–based diet and behavior expert Charlotte Markey. She is the author of an upcoming cover story in Scientific American MIND on this topic, and spoke about the Coke claims with Scientific American on Monday. In your fall Scientific American MIND feature you write “study after study shows that working out is not terribly effective for weight loss on its own.” Why is that? Exercise increases appetite, and most people just make up for whatever they exercised off. There’s a lot of wonderful reasons to exercise and I always suggest it to people who are trying to lose weight—some sort of exercise regimen keeps them focused on their health and doing what is good for them, and it’s psychologically healthy. But in and of itself it won’t usually help people lose weight. Two years ago there was a review study in Frontiers in Psychology that concluded dieting often actually led to weight gain. Why would that happen? When people try to diet, they try to restrict themselves, which often leads to overeating. They cut out food groups which make those food groups more desirable to them. They think too much about short-term goals and don’t think about sustainable changes. But if you are going to lose weight, you have to change your behaviors for the rest of your life or otherwise you gain it back. That’s not a sexy message because it seems daunting. © 2015 Scientific American

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21285 - Posted: 08.12.2015

By Anahad O’Connor Coca-Cola, the world’s largest producer of sugary beverages, is backing a new “science-based” solution to the obesity crisis: To maintain a healthy weight, get more exercise and worry less about cutting calories. The beverage giant has teamed up with influential scientists who are advancing this message in medical journals, at conferences and through social media. To help the scientists get the word out, Coke has provided financial and logistical support to a new nonprofit organization called the Global Energy Balance Network, which promotes the argument that weight-conscious Americans are overly fixated on how much they eat and drink while not paying enough attention to exercise. “Most of the focus in the popular media and in the scientific press is, ‘Oh they’re eating too much, eating too much, eating too much’ — blaming fast food, blaming sugary drinks and so on,” the group’s vice president, Steven N. Blair, an exercise scientist, says in a recent video announcing the new organization. “And there’s really virtually no compelling evidence that that, in fact, is the cause.” Health experts say this message is misleading and part of an effort by Coke to deflect criticism about the role sugary drinks have played in the spread of obesity and Type 2 diabetes. They contend that the company is using the new group to convince the public that physical activity can offset a bad diet despite evidence that exercise has only minimal impact on weight compared with what people consume. This clash over the science of obesity comes in a period of rising efforts to tax sugary drinks, remove them from schools and stop companies from marketing them to children. In the last two decades, consumption of full-calorie sodas by the average American has dropped by 25 percent. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21283 - Posted: 08.10.2015

By Mitch Leslie If you need to lose a lot of weight, surgeons have a drastic option: They can reroute and sometimes remove parts of your stomach, making it smaller. But instead of limiting the amount of food you can eat, the surgery may work by triggering long-term changes in the types of microbes that inhabit your intestines, a new study suggests. If so, altering the kinds of microbes that live in your gut may be a simpler—and safer—route to weight loss. The research provides “some of the best evidence in humans so far” that bariatric surgery works “in part by changing the bacteria in your gut,” says David Cummings, an endocrinologist at the University of Washington, Seattle, who was not involved with the work. Weight loss isn’t the only benefit of so-called bariatric surgery. If a patient has diabetes, for instance, it will usually disappear. The surgery alters metabolism and digestive system functions in several ways, and researchers are still trying to pin down why it’s effective. “This is not about making your stomach small,” says Randy Seeley, an obesity and diabetes researcher at the University of Michigan, Ann Arbor, who wasn’t connected to the study. One way that bariatric surgery might trigger its effects is through its influence on the microbiota, the swarms of microbes that dwell in our intestines and help us digest food. Studies have found that bariatric surgery dramatically alters the microbiota’s makeup in mice and humans. Two years ago, scientists put mice through a Roux-en-Y gastric bypass—a type of bariatric surgery that involves reducing the stomach to a small pouch and stitching it to the middle part of the small intestine—and then transplanted microbes from the slimmed down animals into mice that lacked intestinal bacteria. The recipient rodents lost 5% of their body weight in 2 weeks. But these studies only checked for short-term changes. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21269 - Posted: 08.05.2015

By Roni Caryn Rabin “Fat” cartoon characters may lead children to eat more junk food, new research suggests, but there are ways to counter this effect. The findings underscore how cartoon characters, ubiquitous in children’s books, movies, television, video games, fast-food menus and graphic novels, may influence children’s behavior in unforeseen ways, especially when it comes to eating. Researchers first randomly showed 60 eighth graders a svelte jelly-bean-like cartoon character or a similar rotund character and asked them to comment on the images. Then they thanked them and gestured toward bowls of Starburst candies and Hershey’s Kisses, saying, “You can take some candy.” Children who had seen the rotund cartoon character helped themselves to more than double the number of candies as children shown the lean character, taking 3.8 candies on average, compared with 1.7 taken by children shown the lean bean character. (Children in a comparison group shown an image of a coffee mug took 1.5 candies on average.) But activating children’s existing health knowledge can counter these effects, the researchers discovered. In a separate experiment, they showed 167 elementary school children two red Gumby-like cartoon characters, one fat and one thin, and then asked them to “taste test” some cookies. But they also asked the children to “think about things that make you healthy,” such as getting enough sleep versus watching TV, or drinking soda versus milk. Some children were asked the health questions before being given the cookie taste test, while others were asked the questions after the taste test. Remarkably, the children who were asked about healthy habits before doing the taste test ate fewer cookies — even if they had first been exposed to the rotund cartoon character. Those who were shown the rotund figure ate 4.2 cookies on average if they were asked about healthy habits after eating the cookies, compared to three cookies if they were asked about healthy habits before doing the taste test. Children who saw the normal weight character and who were asked about healthy habits after the taste test also ate about three cookies. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 14: Attention and Consciousness
Link ID: 21228 - Posted: 07.29.2015

Allison Aubrey Bite into that bread before your main meal, and you'll spike your blood sugar and amp up your appetite. Waiting until the end of your dinner to nosh on bread can blunt those effects. Bite into that bread before your main meal, and you'll spike your blood sugar and amp up your appetite. Waiting until the end of your dinner to nosh on bread can blunt those effects. iStockphoto Ah, the bread basket. You sit down for a nice meal out, and there it appears: piping hot, giving off a waft of yeasty divinity. There's a reason this age-old tradition prevails. Even in the era of paleo and gluten-free, there are still hordes of us who will gladly nosh on crusty, chewy, soul-warming bread. But the downside may be more than just some extra calories. Turns out, eating all those carbs before a meal can amp up our appetites and spike our blood sugar. "The worst situation is having refined carbohydrates on an empty stomach, because there's nothing to slow down the digestion of that carbohydrate into sugar," explains David Ludwig, director of the Optimal Weight for Life Clinic at Boston Children's Hospital. © 2015 NPR

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 21108 - Posted: 06.30.2015