Links for Keyword: Obesity

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By Emily Underwood When a 53-year-old man asked Dutch doctors to treat his obsessive-compulsive disorder (OCD) several years back, they suggested a new but promising surgical treatment: implanted electrodes that would stimulate deep brain tissue involved in decision-making, reward-seeking, and motivation. The treatment apparently helped him go off one of his psychiatric medications, but it came with a surprising side effect—it also seemed to improve his type 2 diabetes. Now, researchers think they know why. A new study suggests that a boost in the activity of dopamine, a neurotransmitter involved in motivation and pleasure, improves the body’s ability to process sugar. This is the first time such a pathway, previously seen in mice, has been found in humans, says Mike Michaelides, a neuroscientist at the National Institute on Drug Abuse in Baltimore, Maryland, who was not involved in the new research. That doesn’t make deep brain stimulation (DBS) realistic for most people with diabetes, but other, less invasive brain therapies that target dopamine might one day be feasible. Diabetes occurs when glucose, or sugar, in a person’s bloodstream remains in chronically high concentrations. Type 1, which typically begins in childhood, results when the immune system destroys the pancreatic cells that make insulin, the hormone that lets our cells use sugar as food. Type 2 diabetes, typically triggered by a combination of bad genes, poor eating habits, and a lack of exercise, also damages the body’s ability to produce its own insulin. As time goes on, cells are hard-pressed to remove sugar from the blood, and people require larger and larger amounts of insulin to keep their blood sugar stable. There is no cure for either disease. © 2018 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 25018 - Posted: 05.24.2018

Nicola Davis With 26% of adults classified as obese in the UK in 2016, the hunt for causes and solutions to expanding waistlines is on. While public health messages have focused largely on the food we eat, some scientists suspect there is another factor at play: substances being dubbed as “obesogens” – found in our packaging, household goods and furnishings that might affect our hormones and the buildup of fat in the body. However, experts are sceptical, particularly in the light of one report this week. It has made the bold claim that “removing shoes when entering the house and swapping carpet for wooden floors could help people stay slim”, citing a talk by researchers at the universities of Aveiro and Beira Interior in Portugal, who have suggested that preventing obesogens accumulating in the house by frequently sweeping and dusting could stop us gaining weight. As Prof Russell Viner, president of the Royal College of Paediatrics and Child Health, says: “For some medical reasons, such as protection against allergies, yes, it’s advised to keep a dust-free home and so, too, is removing shoes to avoid bringing in dirt from outside, but these things will not make you a healthy weight. Only a balanced diet and regular exercise will do that.” It is not the first study to moot the idea of the existence of obesogens. Earlier this year, researchers at Harvard University suggested compounds called perfluoroalkyl substances (PFAS) – widely used in products such as stain repellents and known to have a number of negative effects on human health – might lead to weight gain. © 2018 Guardian News and Media Limited

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 25005 - Posted: 05.22.2018

Robin McKie, science editor Fasting every other day to lose weight could have damaging side effects. That is the conclusion of a group of scientists speaking this weekend at the European Society of Endocrinology’s annual meeting. Their findings suggest that fasting-based diets may impair the action of sugar-regulating hormone insulin, and lead to increased risk of diabetes. Care should be taken before starting such programmes, say researchers. Ana Bonassa, whose team from the University of São Paulo in Brazil carried out the study, said: “This is the first study to show that, despite weight loss, intermittent fasting diets may actually damage the pancreas and affect insulin function in normal healthy individuals, which could lead to diabetes and serious health issues.” Advertisement In recent years intermittent fasting diets have gained popularity. Participants fast for two days out of seven, or on alternate days. However, evidence of their success has been contradictory and there is debate among doctors about their potential to trigger harmful long-term effects. Previous research has also shown that short-term fasting can produce molecules called free radicals, highly reactive chemicals that can cause damage to cells in the body and which may be associated with impaired organ function, cancer risk and accelerated ageing. © 2018 Guardian News and Media Limited

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 25001 - Posted: 05.21.2018

By Kirstie Brewer BBC News People might think battling obesity is down to sheer willpower, but medical research says otherwise. Here are five potentially surprising factors that can affect your weight, as unearthed by The Truth About Obesity . 1. Gut microbes Gillian and Jackie are twins - but one weighs over six stone (41kg) more than the other. Prof Tim Spector has been tracking their progress over 25 years, as part of the Twins Research UK study. He believes a lot of their weight differences are down to the tiny organisms - microbes - that live deep in the gut. "Every time you eat anything, you're feeding a hundred trillion microbes. You're never dining alone," he says. A stool sample from each twin revealed Gillian, the thinner of the two, had a very diverse range of microbes, whereas Jackie had very few species living in her gut. "The greater the diversity, the skinnier the person. If you're carrying too much weight, your microbes aren't as diverse as they should be," says Prof Spector, who found the same pattern in a study of 5,000 people. Image copyright Science Photo Library Having a healthy and varied diet, rich in different sources of fibre, has been shown to create a more diverse range of gut microbes. Prof Spector warns most Britons eat only half the fibre they should. 2. The gene lottery Why do some people diligently follow diets and exercise regularly but still struggle to see results, while others do very little and don't pile on the pounds? Scientists at Cambridge University believe 40-70% of the effect on our weight is down to variation in the genes we inherit. © 2018 BBC

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24922 - Posted: 04.30.2018

By Kerry Grens Thermometers in the mouse brain are responsible for a lack of appetite the animals feel after a vigorous workout. Simply firing up heat-sensing receptors on cells in the mouse hypothalamus can reproduce the same appetite-suppressing effects of exercise, researchers report today (April 24) in PLOS Biology. “Our study provides evidence that body temperature can act as a biological signal that regulates feeding behavior, just like hormones and nutrients do,” says coauthor Young-Hwan Jo, a neuroscientist at Albert Einstein College of Medicine, in a press release. It’s a fairly common observation among people that working out staves off hunger for a short while afterward. And it turns out the same is true in mice. Jo’s group had mice run a treadmill for 40 minutes, and observed that their brains were warmer and they ate less for the next hour. To see what might be responsible for this effect, Jo and his colleagues centered in on the hypothalamus, given its role in regulating eating. They found that in mice, neurons in the hypothalamus—specifically, in the arcuate nucleus (ARC) of the hypothalamus—produce heat-sensitive receptors called TRPV1. Through a variety of methods, including the application of capsaicin, a compound found in hot chili peppers, the investigators revealed that flipping on TRPV1 could tamp down mice’s appetites. On the flip side, disrupting the receptor wiped out the appetite-suppressing effects of exercise. © 1986-2018 The Scientist

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 5: The Sensorimotor System
Link ID: 24901 - Posted: 04.26.2018

Alexey Ponomarenko & Tatiana Korotkova The body’s basic needs include a timely supply of nutrients and the avoidance of tissue damage, which are signalled in the brain by hunger and pain, respectively. But these needs cannot be fulfilled simultaneously, because their resolution involves mutually exclusive behaviours. How does the brain prioritize the more urgent need? Writing in Cell, Alhadeff et al.1 report that the brain’s priorities are set depending on the type of pain involved. Hunger-mediating neurons suppress long-term inflammatory pain, but acute pain, which signals an immediate threat, dampens the activity of these neurons and thus deprioritizes feeding. Alhadeff and colleagues deprived mice of food for 24 hours, and analysed how the hungry animals responded to pain. The researchers found that responses to long-term inflammatory pain — of the type associated with chronic disease and recovery from injury — were reduced in the food-deprived animals compared with controls. By contrast, short-term responses to acute pain that was induced by chemicals, heat or force remained intact in hungry mice. The brain’s hypothalamus contains several structures involved in regulating food intake. One of these, the arcuate nucleus, harbours a population of neurons that express agouti-related protein (AgRP), and help to signal nutritional needs — activation of these neurons evokes voracious feeding2, whereas their ablation leads to starvation3,4. Alhadeff et al. found that stimulation of the AgRP-expressing neurons mimicked the pain-inhibiting effect of hunger in mice. By contrast, silencing of these cells blocked the reduction of inflammatory pain. © 2018 Macmillan Publishers Limited,

Related chapters from BN8e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24896 - Posted: 04.24.2018

By Kerry Grens A variant in the gene for a certain hormone is tied to people eating more carbs. Yet a new study of 451,000 people finds that the allele doesn’t universally mean poorer health. Researchers reported yesterday (April 10) in Cell Reports that those with the sweet-tooth variant actually have lower body fat than others, and no higher risk for type 2 diabetes. They did, however, find a link between the allele and high blood pressure and a thicker waistline. “This goes against the current perception that eating sugar is bad for health. It may reduce body fat because the same allele also results in a lower consumption of protein and fat in the diet,” study coauthor Timothy Frayling, a molecular geneticist at the University of Exeter Medical School in the U.K., says in a press release. “But whilst this version of the gene lowers body fat, it also redistributes fat to the upper body, where it’s more likely to cause harm, including higher blood pressure.” The gene of interest here is FGF21, which encodes fibroblast growth factor 21, a hormone involved in alcohol and sugar consumption and insulin sensitization. The authors note that it’s a target of weight loss interventions. People with a particular allele of FGF21—20 percent of Europeans are homozygous for the variant—tend to consume relatively more sugar and alcohol than those without the allele. To see what consequences this might have on people’s health, Frayling and his colleagues collected data on 451,000 people whose genetic and health information is part of the UK Biobank. © 1986-2018 The Scientist

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24855 - Posted: 04.12.2018

By GRETCHEN REYNOLDS If you give a mouse a running wheel, it will run. But it may not burn many additional calories, because it will also start to move differently when it is not on the wheel, according to an interesting new study of the behaviors and metabolisms of exercising mice. The study, published in Diabetes, involved animals, but it could have cautionary implications for people who start exercising in the hopes of losing weight. In recent years, study after study examining exercise and weight loss among people and animals has concluded that, by itself, exercise is not an effective way to drop pounds. In most of these experiments, the participants lost far less weight than would have been expected, mathematically, given how many additional calories they were burning with their workouts. Scientists involved in this research have suspected and sometimes shown that exercisers, whatever their species, tend to become hungrier and consume more calories after physical activity. They also may grow more sedentary outside of exercise sessions. Together or separately, these changes could compensate for the extra energy used during exercise, meaning that, over all, energy expenditure doesn’t change and a person’s or rodent’s weight remains stubbornly the same. Proving that possibility has been daunting, though, in part because it is difficult to quantify every physical movement someone or something makes, and how their movements do or do not change after exercise. Mice, for instance, skitter, dart, freeze, groom, eat, roam, defecate and otherwise flit about in frequent fits and starts. But recently, animal researchers hit upon the idea of using infrared light beams to track how animals move at any given moment in their cages. Sophisticated software then can use that information to map daily patterns of physical activity, showing, second-by-second, when, where and for how long an animal roams, sits, runs or otherwise spends its time. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24848 - Posted: 04.11.2018

By Catherine Offord A tadpole has a lot of growing to do to get up to the size it needs to be to metamorphose into an adult frog or toad. Now, researchers at the University of Michigan suggest that this rapid growth is made possible by a lack of inhibitory feeding controls prior to metamorphosis. The team reports the absence of these controls, along with the hormonal regulation that accompanies it, today (March 28) in Proceedings of the Royal Society B. “Our findings are consistent with the hypothesis that the strong drive to eat prior to metamorphosis is due to the absence, or the relative immaturity of hypothalamic feeding control circuits,” the authors write in their paper. This lack of inhibition helps allow “the animal to maximize growth during this critical life-history stage.” Previous work by the researchers had implicated a role for leptin, a hormone that acts as a hunger inhibitor in vertebrates, in regulating the changing feeding habits of toads during early development. To investigate how this hormone might prepare juvenile amphibians for metamorphosis, the team analyzed levels of mRNA transcripts for leptin receptor proteins and for the hormone itself in tadpoles of the African clawed frog (Xenopus laevis). The researchers found that the tadpoles were essentially unresponsive to leptin, unlike their adult counterparts, and showed minimal expression of the leptin receptor in the hypothalamus—a key brain region in the regulation of feeding behavior. Instead, these responses develop as the relevant neural circuits mature during metamorphosis, the authors write. © 1986-2018 The Scientist

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24796 - Posted: 03.29.2018

by David Kohn This is a story about the importance of good timing. Two-thirds of Americans are overweight or obese. This excess weight contributes to a variety of health problems. Despite enormous effort over decades, the problem has proved extremely difficult to solve. Biologist Satchin Panda thinks we’re missing a key variable: Instead of focusing so much on what we eat, he says, we should pay more attention to when we eat. A researcher at the Salk Institute in San Diego, Panda argues that eating within a certain time window each day can help people lose weight and may help prevent illnesses including diabetes, heart disease and cancer. In animal studies, he and others have shown that limiting food intake to a period of eight to 12 hours can boost cognitive and physical performance, and may even lengthen life span. Known as time-restricted feeding, or TRF, the approach is simple: Eat more or less what you want, but don’t consume anything before or after the allotted time. Panda argues that humans’ circadian rhythm is not designed for a world with 24-7 access to food. “If you’re eating all the time, it messes up that pattern,” he says. For many if not most Americans, that pattern is deeply out of whack, and many of us eat from early morning until late at night. © 1996-2018 The Washington Post

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24785 - Posted: 03.27.2018

By Aaron E. Carroll The endless array of diets that claim to help you shed pounds tend to fall into two camps: low fat or low carbohydrate. Some companies even claim that genetics can tell us which diet is better for which people. A rigorous recent study sought to settle the debate, and it had results to disappoint both camps. On the hopeful side, as The New York Times noted, people managed to lose weight no matter which of the two diets they followed. The study is worth a closer look to see what it did and did not prove. Researchers at Stanford University took more than 600 people (which is huge for a nutrition study) aged 18 to 50 who had a body mass index of 28 to 40 (25-30 is overweight, and 30 and over is obese). The study subjects had to be otherwise healthy. They couldn’t even be on statins, or drugs for Type 2 diabetes or hypertension, which might affect weight or energy expenditure. They were all randomly assigned to a healthful low-fat or a healthful low-carbohydrate diet, and they were clearly not blinded to which group they were in. All participants attended 22 instructional sessions over one year in groups of about 17 people. The sessions were held weekly at first and were then spaced out so that they were monthly in the last six months. Everyone was encouraged to reduce intake of the avoided nutrient to 20 grams per day over the first eight weeks, then participants slowly added fats or carbohydrates back to their diets until they reached the lowest level of intake they believed could be sustained for the long haul. Everyone was followed for a year (which is an eternity for a nutrition study). Everyone was encouraged to maximize vegetable intake; to minimize added sugar, refined flour and trans fat intake; and to focus on whole foods that were minimally processed. The subjects were also encouraged to cook at home as much as possible. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24783 - Posted: 03.26.2018

Aimee Cunningham As mice plumped up on a high-fat diet, some of their taste buds vanished. This disappearing act could explain why some people with obesity seem to have a weakened sense of taste, which may compel them to eat more. Compared with siblings that were fed normal mouse chow, mice given high-fat meals lost about 25 percent of their taste buds over eight weeks. Buds went missing because mature taste bud cells died off more quickly, and fewer new cells developed to take their place. Chronic, low-level inflammation associated with obesity appears to be behind the loss, researchers report March 20 in PLOS Biology. Taste buds, each a collection of 50 to 100 cells, sense whether a food is sweet, sour, bitter, salty or umami (savory). These cells help identify safe and nourishing food, and stimulate reward centers in the brain. The tongue’s taste bud population is renewed regularly; each bud lasts about 10 days. Special cells called progenitor cells give rise to new taste bud cells that replace old ones. Some studies have suggested that taste becomes duller in people with obesity, although why that is has remained unclear. But if taste becomes less intense, “then maybe you don’t get the positive feeling that you should,” which could give way to more overeating, says study coauthor Robin Dando, who studies the biology of taste at Cornell University. Nearly 40 percent of U.S. adults have obesity, determined by a person’s body mass index, a ratio of weight to height. The condition is linked to a number of health problems, including heart disease, diabetes and cancer. |© Society for Science & the Public 2000 - 2018

Related chapters from BN8e: 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: 24777 - Posted: 03.21.2018

By JANE E. BRODY When The New York Times hired me to write about science and health 52 years ago, I was 40 pounds overweight. I’d spent the previous three years watching my weight rise as I hopped from one diet to the next in a futile attempt to shed the pounds most recently gained. No amount of exercise, and I did plenty of it, could compensate for how much I ate when I abandoned the latest weight loss scheme. I had become a living example of the adage: A diet is something one goes on to go off. Even daylong fasting failed me. When I finally ate supper, I couldn’t stop eating until I fell asleep, and sometimes awoke the next morning with partly chewed food in my mouth. I had dieted myself into a binge-eating disorder, and that really scared me. Clearly, something had to change. I finally regained control when I stopped dieting. I decided that if I was going to be fat, at least I could be healthy. I made a plan to eat three nutritious, satisfying meals every day with one small snack, which helped me overcome the temptation to binge in response to deprivation. Much to my surprise, a month later I had lost 10 pounds — eating! Eating good food, that is, and plenty of it. I continued the regimen without difficulty because it was not a diet. It was a way to live and a healthy one at that. And I continued to lose, about two pounds a month. Two years later, all the excess weight was gone. I never gained it back and never again went on a diet. (Even with a twin pregnancy, I gained only 36 pounds and lost them all when my sons were born at 6 pounds 13 ounces each.) The greatest challenge to lasting weight loss, especially for someone like me with a food addiction, is the fact that no one can give up eating. Rather, one has to learn a better — and permanent — way to handle food. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24723 - Posted: 03.06.2018

By NICHOLAS BAKALAR Some experts have suggested that there is an “obesity paradox,” the idea that obese people live longer than those of normal weight. But a new study found that obesity was associated with an increased risk for cardiovascular disease and a two- to three-year shorter life span. The study, in JAMA Cardiology, pooled data from 10 studies of 190,672 people followed from 1964 to 2015. Compared with those of normal weight, overweight men (body mass index of 25 to 29.9) had a 21 percent higher lifetime risk of cardiovascular disease and women a 32 percent higher risk. Among the obese (B.M.I. of 30 to 39.9), the risk was 67 percent higher for men and 85 percent higher for women, with even higher risk for those with a B.M.I. over 40. Longevity in men who were overweight but not obese was similar to that of men of normal weight. But they had an increased risk of cardiovascular disease at a younger age. “We were able to measure how much time is spent in healthy life years rather than just life span,” said the study’s senior author, Dr. Sadiya S. Khan, an assistant professor of medicine at Northwestern. “Maintaining a healthy B.M.I. is associated with a longer, healthier life, with less risk for cardiovascular disease.” © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24712 - Posted: 03.01.2018

By NICHOLAS BAKALAR Overweight mothers are more likely to have overweight babies, and the gut bacteria the babies inherit may in part be to blame. Researchers report that overweight mothers are more likely to have a cesarean section, and that babies born by cesarean to those mothers have species of gut bacteria different from those in babies born to normal weight women. And that difference in the gut microbiome — specifically an abundance of bacteria of the family Lachnospiraceae in infants of overweight mothers — may contribute to an increased risk for obesity. The study included 935 mother-infant pairs. Compared to children born to normal weight mothers, those born vaginally to overweight women were more than three times as likely to be overweight by age 3. But C-section babies born to overweight mothers were more than five times as likely to be overweight. For normal weight mothers, vaginal or C-section delivery made no difference in the risk for overweight babies. The study, in JAMA Pediatrics, controlled for breast-feeding, antibiotic exposure and other factors. The senior author, Anita L. Kozyrskyj, a professor of pediatrics at the University of Alberta, said that there is no probiotic that would lead to a positive change in gut bacteria. “If a cesarean is unavoidable, there is no easy answer,” she added, “but breast-feeding is effective in helping to prevent infants from becoming overweight.” © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24711 - Posted: 03.01.2018

By Aaron E. Carroll I remember the first time my daughter discovered her hand. The look of amazement on her face was priceless. It wasn’t long before she was putting that discovery to use, trying to put everything she could find into her mouth. Babies want to feed themselves. It sometimes feels as if parents spend more time trying to stop them than encouraging them. Over the last few years, however, some people have begun to ask if we are doing the right thing. Baby-led weaning is an approach to feeding that encourages infants to take control of their eating. It’s based on the premise that infants might be better self-regulators of their food consumption. It has even been thought that baby-led weaning might lead to reductions in obesity. While babies have been spoon-fed for a long time, the explosion of commercial foods for them might be making it too easy to overfeed them, an idea that the results from a cohort study in 2015 seemed to hint at. Those weaned in a baby-led approach seemed to be more responsive to being sated and were less likely to be overweight. A case-control study from 2012 also argued that baby-led weaning was associated with a lower body mass index (B.M.I). Such trials cannot establish causality, however, and may be confounded in unmeasured ways. A recent randomized controlled trial accomplished what previous work could not. Pregnant women in New Zealand were recruited before they gave birth and randomly assigned to one of two groups. Both got standard midwifery and child care. But one group received eight more contacts, from pregnancy to the newborn’s ninth month. Five of these were with a lactation consultant, who encouraged the mothers to prolong breast-feeding and delay the introduction of solid foods until 6 months of age. The three other contacts were with research staffers who encouraged parents to read hunger and fullness cues from their infants and provide their babies (starting at 6 months) with foods that were high in energy and iron — easy to grab but hard to choke on. © 2018 The New York Times Company

Related chapters from BN8e: 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: 24701 - Posted: 02.27.2018

By ANAHAD O’CONNOR Anyone who has ever been on a diet knows that the standard prescription for weight loss is to reduce the amount of calories you consume. But a new study, published Tuesday in JAMA, may turn that advice on its head. It found that people who cut back on added sugar, refined grains and highly processed foods while concentrating on eating plenty of vegetables and whole foods — without worrying about counting calories or limiting portion sizes — lost significant amounts of weight over the course of a year. The strategy worked for people whether they followed diets that were mostly low in fat or mostly low in carbohydrates. And their success did not appear to be influenced by their genetics, a finding that casts doubt on the increasingly popular idea that different diets should be recommended to people based on their DNA makeup. The research lends strong support to the notion that diet quality, not quantity, is what helps people lose and manage their weight most easily in the long run. It also suggests that health authorities should shift away from telling the public to obsess over calories and instead encourage Americans to avoid processed foods that are made with refined starches and added sugar, like bagels, white bread, refined flour and sugary snacks and beverages, said Dr. Dariush Mozaffarian, a cardiologist and dean of the Friedman School of Nutrition Science and Policy at Tufts University. “This is the road map to reducing the obesity epidemic in the United States,” said Dr. Mozaffarian, who was not involved in the new study. “It’s time for U.S. and other national policies to stop focusing on calories and calorie counting.” The new research was published in JAMA and led by Christopher D. Gardner, the director of nutrition studies at the Stanford Prevention Research Center. It was a large and expensive trial, carried out on more than 600 people with $8 million in funding from the National Institutes of Health, the Nutrition Science Initiative and other groups. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24685 - Posted: 02.21.2018

Nicola Davis While you might be tempted to wolf down a sandwich or gobble up your dinner, researchers say there may be advantages to taking your time over a meal. According to a study looking at type 2 diabetics, eating slowly could help prevent obesity, with researchers finding a link to both lower waist circumference and body mass index (BMI). “Interventions aimed at altering eating habits, such as education initiatives and programmes to reduce eating speed, may be useful in preventing obesity and reducing the risk of non-communicable diseases,” the authors write. The latest study is not the first to suggest that taking a sedate pace at the dinner table could be beneficial: various pieces of work have hinted that those who eat quickly are more likely to be overweight, have acid reflux and have metabolic syndrome. The latest study, published in the journal BMJ Open by researchers in Japan, looked at data collected though health checkups and claims from more than 59,700 individuals as part of health insurance plans, with data spanning from 2008 to mid-2013. As part of the health checkup, participants were asked seven questions about their lifestyle, including whether their eating speed was fast, normal or slow, whether they snacked after dinner three times or more a week, and whether they skipped breakfast three times or more a week. © 2018 Guardian News and Media Limited

Related chapters from BN8e: 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: 24653 - Posted: 02.13.2018

By ANDREW JACOBS SANTIAGO, Chile — They killed Tony the Tiger. They did away with Cheetos’ Chester Cheetah. They banned Kinder Surprise, the chocolate eggs with a hidden toy. The Chilean government, facing skyrocketing rates of obesity, is waging war on unhealthy foods with a phalanx of marketing restrictions, mandatory packaging redesigns and labeling rules aimed at transforming the eating habits of 18 million people. Nutrition experts say the measures are the world’s most ambitious attempt to remake a country’s food culture, and could be a model for how to turn the tide on a global obesity epidemic that researchers say contributes to four million premature deaths a year. “It’s hard to overstate how significant Chile’s actions are — or how hard it has been to get there in the face of the usual pressures,” said Stephen Simpson, director of the Charles Perkins Centre, an organization of scholars focused on nutrition and obesity science and policy. The multibillion dollar food and soda industries have exerted those pressures to successfully stave off regulation in many other countries. Since the food law was enacted two years ago, it has forced multinational behemoths like Kellogg to remove iconic cartoon characters from sugary cereal boxes and banned the sale of candy like Kinder Surprise that use trinkets to lure young consumers. The law prohibits the sale of junk food like ice cream, chocolate and potato chips in Chilean schools and proscribes such products from being advertised during television programs or on websites aimed at young audiences. Beginning next year, such ads will be scrubbed entirely from TV, radio and movie theaters between 6 a.m. and 10 p.m. In an effort to encourage breast-feeding, a ban on marketing infant formula kicks in this spring. The linchpin of the initiative is a new labeling system that requires packaged food companies to prominently display black warning logos in the shape of a stop sign on items high in sugar, salt, calories or saturated fat. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 24633 - Posted: 02.08.2018

By RONI CARYN RABIN Most dieters know the hard truth: Sticking to a weight loss regimen gets more difficult as the day wears on. But while those who give in to food cravings and binge at night may blame flagging willpower, a new study suggests the problem could lie in the complex orchestra of hormones that drive hunger and signal feelings of satiety, or fullness. The small study of 32 obese men and women, half of whom had a habit of binge eating, suggests that satiety hormones may be lower during the evening hours, while hunger hormones rise toward nightfall and may be stoked even higher by stressful situations. Overweight binge eaters may be particularly susceptible to the influence of fluctuations in these appetite-regulating hormones, the researchers found. “There’s more opportunity to eat in the evening, but this study is showing that hormonal responses are setting them up to do this,” said Susan Carnell, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine who was a first author of the study along with Charlotte Grillot of Florida State University. It’s not clear whether these hormonal patterns precede and cause the binge eating behaviors or are conditioned by an individual’s eating habits, Dr. Carnell said. But either way, “you can get stuck in the cycle.” The study is an important reminder that myriad factors contribute to weight gain, and that shaming and blaming people for their weight problems is inappropriate, said Kelly Costello Allison, director of the Center for Weight and Eating Disorders at the University of Pennsylvania, who was not involved in the new research. © 2018 The New York Times Company

Related chapters from BN8e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 8: Hormones and Sex
Link ID: 24591 - Posted: 01.31.2018