Category: Diet and Weight Loss

A high protein diet during development primes the body to react unhealthily to future food binges. A study on juvenile rats, published in BioMed Central's open access journal Nutrition and Metabolism, suggests that lasting changes result from altering the composition of the first solid food that is consumed throughout growth into early adulthood.

Raylene Reimer worked with a team of researchers from the University of Calgary, Canada, to carry out the weaning experiments in 18 litters of rats. Six litters were placed on each of three diets: high prebiotic fiber, high protein and normal control. They consumed these diets until they were 14 weeks old, when they were switched to a high fat, high sugar diet for a further six weeks. Reimer said, "After a weaning diet high in protein, the rats demonstrated an increase in body weight and fat mass in response to the high energy diet. They also showed higher energy intake than the fiber-diet rats".

This is the first study to investigate the long-term effects of high protein or fiber diets during development on the response to future food intake.

Speaking about the results, Reimer said, "Overall, it appears that a long-term diet high in protein, when mismatched with a high energy challenge, has negative effects on body mass and hormones and genes involved in glucose and lipid metabolism. However, a fiber-enriched diet may provide some protection".

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Journal Reference:

1. Alannah D Maurer, Lindsay K Eller, Megan C Hallam, Kim Taylor and Raylene A Reimer. Consumption of diets high in prebiotic fiber or protein during growth influences the response to a high fat and sucrose diet in adulthood in rats. Nutrition & Metabolism, 2010; (in press) 

 A new University of Michigan study finds that college women with roommates who weigh more than average gain less weight during their freshman year than women with slimmer roommates: half a pound versus 2.5 pounds.

That compares to the typical freshman weight gain of 2.5-to-6 pounds — much less than the mythical "Freshman 15."

"This finding seems counterintuitive, but there are some good explanations for why it may be happening," said Kandice Kapinos, an assistant research scientist at the U-M Institute for Social Research.

According to Kapinos, a labor and health economist, heavier roommates are more likely than average-weight women to diet. They also exercise more often and are more likely to use weight loss supplements and purchase college meal plans that limit access to food.

"It's not really the weight of your roommate that's important, but the behaviors your roommate engages in," Kapinos said. "These behaviors are what may really be 'contagious.'"

Kapinos conducted the study with Marquette University economist Olga Yakusheva. The study is the first to assess college weight gain using a natural experiment occurring on most college campuses in the United States — randomized roommate assignments.

"Previous studies have suggested that having an obese spouse, friend or sibling increases one's likelihood of becoming obese," Kapinos said. "But these relationships are obviously not random. People pick their friends and spouses, and they often select people who are similar to themselves. And even though we don't pick our siblings, we share a genetic inheritance and an early environment that may influence adult weight."

For the current study, which was presented this summer at the annual meeting of the American Society of Health Economists, the researchers assessed 144 female college students randomly assigned to share a living situation during their freshman year. At the start of the fall semester, the researchers obtained the women's weight and height, and asked about weight management behaviors. These included whether they had tried to lose weight at any time during the previous year, the average number of times per week they went to the gym and exercised outside, and whether they had signed up for an unlimited college meal plan.

The topic of peer influences on weight gain and weight management is important since obesity prevalence in young adults, aged 18 to 29, increased by 96 percent from 1988 to 2006 — the largest percentage increase for all age groups.

Another study Kapinos and Yakusheva conducted found that freshmen assigned to dormitories with onsite dining halls gained more weight than those who had to venture outside of their dorms for food. Later this fall, the researchers will expand their study of the issue by analyzing a larger sample of students at a public university to see if roommate weight patterns persist. They will also examine other environmental influences and see if the findings vary with race, ethnicity or socioeconomic status.

"Our hope is that this line of research will have practical implications for university administrators and more generally for public health efforts aimed at reducing obesity," Kapinos said.

Physician's confidence in their ability to counsel patients on a healthy diet and exercise may be related to their own personal habits, according to a study by the University of Michigan Cardiovascular Center.

Factors that predicted confidence in counseling included the doctor's own exercise time, being overweight, and if the doctor had adequate training in counseling patients.

The study, published online ahead of print Oct. 1 in Preventive Cardiology, shows doctors' own health habits matter when it comes to patient counseling.

"Living a healthy lifestyle themselves translates into a more believable message to their patients," says lead author Michael Howe, M.D., chief medical resident at U-M Health System. "Physicians are busy, especially during their training; but eating healthy foods and exercising regularly may result in better personal health as well as improved patient care."

A majority of attending physicians, those who have completed their doctor training, talked to patients about a healthy diet compared to only 36 percent of trainees, young doctors still in internship or residency programs.

But in the survey, attending physicians reported taking better care of themselves than trainees whose diets were heavier in fast food.

Both attending and trainee physicians reported low levels of confidence in their ability to effectively counsel patients regarding healthy lifestyle habits. However, greater degrees of self-confidence for counseling were seen with increased levels of personal exercise.

Attending physicians were more likely to exercise four or more days a week and more than 150 minutes a week than trainees. In the survey, 69 percent talked to patients about exercise compared to only 38 percent of trainees who gave exercise counseling.

Few trainees or attending physicians were confident in their ability to change patients' behavior even though it's well-known that weight loss can prevent or alleviate obesity-related diseases such as hypertension and diabetes.

Factors that predicted confidence in counseling included the doctor's own exercise time, being overweight, and if the doctor had adequate training in counseling, the study showed.

Adequate training was the strongest predictor for confidence in talking about healthy eating habits, the survey showed.

With the prevalence of obesity among adults in the U.S. increasing, "many physicians lack confidence in their ability to counsel patients regarding lifestyle," says senior author Elizabeth Jackson, M.D., an assistant professor of internal medicine at the U-M Health System. "An emphasis on healthy diet and exercise counseling is an important part of medical education for physicians of all levels."

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Journal Reference:

1. Michael Howe, Adam Leidel, Sangeetha M. Krishnan, Alissa Weber, Melvyn Rubenfire, Elizabeth A. Jackson. Clinical Study: Patient Related Diet and Exercise Counseling: Do Providers’ Own Lifestyle Habits Matter?Preventive Cardiology, 2010; DOI: 10.1111/j.1751-7141.2010.00079.x

Many people have experienced the frustration that comes with regaining weight that was lost from dieting. According to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM), the levels of appetite hormones in the body prior to dieting may serve as a predictor of weight regain after dieting.

"Treating obesity with drugs or dietary programs can be very effective in the short-term, but the long-term success of maintaining the weight lost is usually poor," said Ana Crujeiras, PhD, of Compejo Hospitalario Universitario de Santiago in Spain and lead author of the study. "Our study sheds light on how the appetite hormones leptin and ghrelin affect weight regain after weight loss. This knowledge could be used as a tool to personalize weight-loss programs that could guarantee success in keeping off the weight."

In this study, researchers evaluated a group of 104 obese or overweight men and women during an 8-week low-calorie diet and again 32 weeks after treatment. Researchers measured body weight as well as plasma fasting ghrelin, leptin and insulin concentrations before, during and after dieting. They found that subjects with higher plasma leptin and lower ghrelin levels before dieting were more prone to regain weight lost after dieting and that these hormone levels could be proposed as biomarkers for predicting obesity-treatment outcomes.

"We believe this research is of foremost relevance in clinical terms as it may indicate that the outcome of weight therapy may be pre-conditioned," said Crujeiras. "Furthermore, our findings may provide endocrinology and nutrition professionals a tool to identify individuals in need of specialized weight-loss programs that first target appetite hormone levels before beginning conventional dietary treatment."

Other researchers working on the study include: Estíbaliz Goyenechea, Itziar Abete and J. Alfredo Martínez of the University of Navarra in Spain; and Mary Lage, Marcos Carreira and Felipe Casanueva of Compejo Hospitalario Universitario de Santiago in Spain. Both research groups belong to the Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), an Instituto de Salud Carlos III iniciative.

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Journal Reference:

1. Ana B. Crujeiras, Estíbaliz Goyenechea, Itziar Abete, Mary Lage, Marcos C. Carreira, J Alfredo Martínez, Felipe F. Casanueva. Weight Regain after a Diet-Induced Loss Is Predicted by Higher Baseline Leptin and Lower Ghrelin Plasma Levels. Journal of Clinical Endocrinology & Metabolism, 2010; DOI: 10.1210/jc.2009-2566

Nutritional science and food marketing has become so sophisticated in recent decades that a trip to the supermarket can require a complete nutritional re-education. The average consumer needs to be on guard against preservatives, added fat, colorings, and calories, false advertising, and sophisticated but misleading labels.

Although guidelines for the information of food labels have gotten a bad rap in recent years, a new study published in the Journal of Consumer Affairs suggests that observing them may lead to weight loss, especially for women entering their middle years. The study was authored by Bidisha Mandal, PhD, an assistant professor at the School of Economic Sciences at Washington State University.

Using information on whether consumers read food labels the first time they buy a product, the study's author found that people who observe the labels and do not exercise display a slightly greater likelihood of weight loss than those who do exercise but do not pay attention to food labels. By simply adding an exercise routine to their lifestyle regular food label readers can increase their changes of losing weight. Women between the ages of 37-50 years are more likely to read food labels than men, and are therefore more likely to lose weight, according to the study.

Previous research has focused on food marketing and behaviour but has not followed related weight loss over time in this middle-aged demographic group. The data for this study was taken from a National Longitudinal Survey of Youth compiled from 2002-2006. The survey began in 1979 with over 12,000 male and female participants born in the years 1957-1964.

Over fifty percent of participants reported that they were trying to lose or control weight. Of these participants, almost seventy percent were obese or overweight. Almost fifty percent were actively reading food labels on their first time purchase and slightly more than twenty-five percent were actively participating in vigorous exercise. Overall, older individuals are less likely to lose weight by reading food labels, and general participation in vigorous exercise drops off after age forty-five.

Additionally, the Nutrition Labeling and Education Act (NLEA), enacted in 1994, requires all food manufactures to present essential nutrient and ingredient information on food packages. According to the recently-passed health care reform bill there will be easier access to nutritional information at restaurants, retail food establishments and vending machines. Combined with these new findings, it is likely that this measure will be useful to those who want to lose weight and read food labels to make well-informed decision regarding their diets in and outside their homes.

Weight loss programs and plans would do well in augmenting their client's weight loss goals with the recommended use of food labels, in order to maintain a healthy weight. This is particularly important as people enter middle age and are at a risk for heart disease, obesity-related diabetes, cancer and dementia.

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Journal Reference:

1. Bidisha Mandal. Use of Food Labels as a Weight Loss Behavior. Journal of Consumer Affairs, 2010; DOI: 10.1111/j.1745-6606.2010.01181.x

 An international study has discovered the reason why some people who eat a high-fat diet remain slim, yet others pile on the weight.

The study, led in Australia by the Monash Obesity and Diabetes Institute (MODI) at Monash University, found a high-fat diet causes brain cells to become insulated from the body preventing vital signals, which tell the body to stop eating and to burn energy, from reaching the brain efficiently.

MODI director and Australian Life Scientist of the Year Professor Michael Cowley said there were two clear outcomes from the findings.

'We discovered that a high-fat diet caused brain cells to become insulated from the body, rendering the cells unable to detect signals of fullness to stop eating," Professor Cowley said.

"Secondly, the insulation also created a further complication in that the body was unable to detect signals to increase energy use and burn off calories/kilojoules."

The research showed that support cells in the brain developed overgrowth in a high-fat diet. This prevented the regular brain cells (the melanocortin system or POMC neurons) from connecting with other neural mechanisms, which determine appetite and energy expenditure.

Professor Cowley said the study findings provide a critical link in addressing the obesity epidemic.

"These neuronal circuits regulate eating behaviours and energy expenditure and are a naturally occurring process in the brain. The circuits begin to form early in life so that people may have a tendency towards obesity even before they eat their first meal," Professor Cowley said.

Eating a high fat diet causes more "insulation" in the nerve cells, and makes it even harder for the brain to help a person lose weight.

"Obese people are not necessarily lacking willpower. Their brains do not know how full or how much fat they have stored, so the brain does not tell the body to stop refuelling. Subsequently, their body's ability to lose weight is significantly reduced."

Professor Cowley and fellow MODI researcher Dr Pablo Enriori collaborated with Research Chair and Professor of Comparative Medicine and Professor of Neurobiology Tamas Horvath and his team at the Yale School of Medicine in the United States, together with teams of scientists in Cincinnati, New Jersey, Mexico and Spain.

For a period of four months, the researchers monitored the eating and body composition of groups of mice and rats and found that those with a neural predisposition to obesity gained 30 per cent more weight compared to six per cent of the group with obesity-resistant cells.

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Journal Reference:

1. T. L. Horvath, B. Sarman, C. Garcia-Caceres, P. J. Enriori, P. Sotonyi, M. Shanabrough, E. Borok, J. Argente, J. A. Chowen, D. Perez-Tilve, P. T. Pfluger, H. S. Bronneke, B. E. Levin, S. Diano, M. A. Cowley, M. H. Tschop. Synaptic input organization of the melanocortin system predicts diet-induced hypothalamic reactive gliosis and obesity. Proceedings of the National Academy of Sciences, 2010; 107 (33): 14875 DOI: 10.1073/pnas.1004282107

Prior research has shown that alcohol abuse and dependence are typically associated with higher rates of obesity, as evidenced by a high body mass index (BMI). Findings from a new study of the relationship between BMI and regional measures of brain structure, metabolite concentrations, and cerebral blood flow suggest that alcohol-related brain injuries may result from a complicated fusion of hazardous drinking, chronic cigarette smoking, and even elevated BMI.

Results will be published in the December 2010 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"Although alcohol doesn't contain fat, it contains seven calories per gram, which comes second only to fat, which has nine calories per gram," said Stefan Gazdzinski, who was a researcher at Northern California Institute for Research and Education in San Francisco when the study was carried out but is now a researcher at Jagiellonian University in Poland. "These calories add up over time. In fact, daily consumption of more than 30 grams of ethanol — the amount of alcohol in two to three 12-ounce beers — is associated with risk for abdominal obesity."

"Abdominal obesity has higher health risks that fat deposition in other body areas, for example, legs and hips," added Susan F. Tapert, a professor of psychiatry at the University of California, San Diego and director of Substance Abuse/Mental Illness in the VA San Diego Healthcare System. "As obesity rates are increasing rapidly among alcoholics and non-alcoholics, these relationships are important to understand."

"Excessive weight is not only a risk factor for cardiovascular disease or diabetes, but it is also a risk factor for developing dementia," said Gazdzinski, also the study's lead author. "Obesity has been shown to be associated with worse decision making and problem solving throughout lifetime. We had previously observed lower concentrations of some brain metabolites, markers of brain injury, in healthy non-alcohol dependent people with BMIs in the overweight to obese range. Knowing that individuals in developed countries who overuse alcohol are usually heavier than individuals enjoying alcohol in moderation — because of the caloric intake — we wanted to investigate if excess weight accounts for some of the brain injury usually observed in alcoholics."

Gazdzinski and his colleagues retrospectively analyzed data gathered from 54 alcohol-treatment seeking men who had been abstinent from alcohol for about one month. BMI, as well as imaging that assessed volume, blood flow, and metabolite concentrations of the brain were obtained from a 1.5 Tesla magnetic resonance scanner.

"It is commonly believed that it is the large amount of consumed alcohol by itself that leads to brain injury in alcoholics," said Dieter J. Meyerhoff, professor of radiology at the University of California San Francisco and San Francisco Veteran's Affairs Medical Center, and the principal investigator of this study. "This is only partly correct. In previous studies, we have shown that alcoholics who smoke cigarettes have greater brain injury than nonsmoking alcoholics. This new study suggests that a high BMI, independent of drinking and smoking, is also associated with brain injury."

"In other words, weight also is related to brain health among those with alcoholism," said Tapert. "BMI may be a very important factor to consider when examining other potential consequences of alcohol use. Since individuals who consume substantial amounts of alcohol are at risk for obesity, it is important to understand the influence of body fat deposition on the measures we are examining. It could be that metabolic changes resulting from or causing obesity cause harm to the brain, at least among alcoholics."

The relationship between alcohol dependence and BMI is complicated, added Gazdzinski. "Alcoholics who drink the most are not necessarily the heaviest," he said. "In our sample, there was no correlation between drinking severity and BMI. Factors such as availability of funds for drinking may play a role, especially in countries where alcohol is heavily taxed. For example, the drinker may have not enough money to eat properly after drinking."

"While it is fortunate that tobacco use, violent crime, and some other unhealthy behaviors have declined in recent years, heavy drinking has remained relatively stable, and obesity rates have greatly increased," said Tapert. "These findings point to another deleterious outcome of becoming overweight: poor brain health. While it may be that poor brain cell functioning has led to the challenges these men faced with overconsumption of food and alcohol, it is also possible that the obesity itself contributed to poor brain health. If so, weight loss, exercise, and improved self-care in addition to stopping drinking could result in improvements to brain health."

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Journal Reference:

1. Stefan Gazdzinski, Timothy C. Durazzo, Anderson Mon and Dieter J. Meyerhoff. Body Mass Index Is Associated With Brain Metabolite Levels in Alcohol Dependence—A Multimodal Magnetic Resonance Study. , 7 SEP 2010 DOI: 10.1111/j.1530-0277.2010.01305.x

Insufficient amounts of nighttime sleep among infants and preschool-aged children may be a significant risk factor for developing childhood obesity, according to a report in the September issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals. Additionally, napping does not appear to be an adequate substitute for nighttime sleep in terms of preventing obesity.

"Obesity — defined as having age- and sex-specific body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) at or above the 95th percentile of national growth standards — has doubled among children aged 2 to 5 years and adolescents aged 12 to 19 years and has tripled among those aged 6 to 11 years" during the last three decades, the authors write as background in the article. "Evidence is accumulating from cross-sectional population studies to support a robust contemporaneous relationship between shortened sleep duration and unhealthy weight status in children and adolescents."

Using existing national, longitudinal and panel survey data collected for children and adolescents, Janice F. Bell, Ph.D., M.P.H., of the University of Washington, Seattle and Frederick J. Zimmerman, Ph.D., of the University of California, Los Angeles, studied 1,930 children ages 0 to 13 years, with data collected on the same children in 1997 (baseline) and again in 2002 (follow-up). For the purposes of the study, children were separated into a "younger" group (age 0 to 59 months) and an "older" group (age 60 to 154 months).

The authors found that, "at follow-up, 33 percent of the younger cohort and 36 percent of the older cohort were overweight or obese." For the younger children, short duration of nighttime sleep at baseline was associated with an increased risk of subsequent overweight or obesity. In the older age group, baseline sleep was not associated with subsequent weight status, however contemporaneous sleep was associated with increased odds of a shift from normal weight to overweight or from overweight to obesity at follow-up. Additionally, in the older group, nighttime sleep at follow-up was associated with marginally increased odds of obesity at follow-up while sleep duration five years prior had no meaningful effect. According to the authors, "these findings suggest that there is a critical window prior to age 5 years when nighttime sleep may be important for subsequent obesity status."

"Sleep duration is a modifiable risk factor with potentially important implications for obesity prevention and treatment," the authors conclude. "Insufficient nighttime sleep among infants and preschool-aged children appears to be a lasting risk factor for subsequent obesity, while contemporaneous sleep appears to be important to weight status in adolescents. Napping had no effects on the development of obesity and is not a substitute for sufficient nighttime sleep."

This study was supported by a grant from the Health Resources and Services Administration/Maternal and Child Health Bureau..

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Journal Reference:

1. Bell et al. Shortened Nighttime Sleep Duration in Early Life and Subsequent Childhood Obesity. Archives of Pediatrics and Adolescent Medicine, 2010; 164 (9): 840 DOI: 10.1001/archpediatrics.2010.143

A study in the Sept. 1 issue of the journal Sleep shows that teens who slept less than eight hours per weeknight ate higher proportions of fatty foods and snacks than adolescents who slept eight hours or more. The results suggest that short sleep duration may increase obesity risk by causing small changes in eating patterns that cumulatively alter energy balance, especially in girls.

Results show that a shorter mean weekday sleep duration was significantly associated with an increase in the percentage of calories consumed from fats and a decrease in the percentage of calories from carbohydrates. After adjusting for potential confounders such as age, sex and race, teens who slept less than eight hours on weeknights consumed 2.2 percent more calories from fats and 3.0 percent fewer calories from carbs than teens who slept eight hours or more. Further adjustments for body mass index (BMI) had little effect on these associations. In secondary analyses stratified by sex, the results were significant among girls but not boys.

"The relative increase in fat consumption among shorter sleepers by 2.2 percent per day chronically may contribute to cumulative increases in energy consumption that would be expected to increase risk for obesity and cardiovascular disease," said senior author and principal investigator Susan Redline, MD, MPH, professor of medicine in the Division of Sleep Medicine at Brigham and Women's Hospital and Beth Israel Deaconess Medical Center, teaching affiliates of Harvard Medical School in Boston, Mass. "The demonstration of chronically altered dietary patterns in adolescents with shorter sleep provides insight into why shorter sleep has been associated with obesity in prior experimental and observational studies."

The study also found a relationship between sleep duration and snacking. For each one-hour increase in sleep duration, the odds of consuming a high amount of calories from snacks decreased by an average of 21 percent. Analyses of sleep duration and timing of nutrient intake revealed that a significantly greater proportion of teens who slept less than eight hours per weeknight consumed food in the early morning between 5 a.m. and 7 a.m.

"Altered timing of eating in shorter sleepers also may be a metabolic stress that contributes to metabolic dysfunction," said Redline.

The study involved 240 teens between 16 and 19 years of age who are participating in the ongoing Cleveland Children's Sleep and Health Study at Case Western Reserve University School of Medicine and Rainbow Babies & Children's Hospital in Cleveland, Ohio. Eighteen percent of participants were obese, defined as being at or above the 95th percentile of BMI for age or having a BMI of 30 or higher.

Sleep was evaluated at home by wrist actigraphy, and average sleep duration was calculated using at least three weeknights of data. The mean weeknight sleep duration was 7.55 hours, and only 34 percent of participants slept for an average of eight hours or more. The American Academy of Sleep Medicine recommends that teens get at least nine hours of sleep each night to feel alert and well rested during the day.

Macronutrient intake was measured using two 24-hour, multipass recall interviews conducted by trained staff. Details were collected about food items and portion sizes, as well as the timing, location, type, and preparation of each meal or snack. Nutrition data were analyzed using the Nutrition Data System for Research, a comprehensive nutrient database.

The authors noted that it is unclear why the association between shorter sleep durations and unhealthy dietary habits may be stronger in girls than boys. However, one explanation may be the increased propensity for female teens to engage in emotional eating.

"Further research is needed to understand how gender may modify the relationship between sleep, stress, metabolism and eating behaviors," Redline said.

The cross-sectional analysis did not allow for an examination of causality. However, Redline states that physiologic studies have identified numerous pathways by which sleep loss may promote weight gain. Reductions in sleep duration may alter metabolic rate and affect the production of leptin and ghrelin, two hormones that regulate appetite. Sleep restriction also may provide increased opportunities to eat, initiate stress responses that promote reward-seeking behaviors such as eating and reduce the physical and motivational drive to exercise.

A CDC study published last January in JAMA reports that the rate of obesity in U.S. adolescents between the ages of 12 and 19 years was 18.1 percent in 2007-2008. The authors concluded that the prevalence of high BMI in childhood has remained steady for 10 years and has not declined despite coordinated prevention efforts.

Redline believes that sleep may be the missing link in obesity interventions that focus only on diet and exercise. She suggests that improving sleep duration should be an essential component of obesity prevention and weight management programs.

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Journal Reference:

1. Weiss A; Xu F; Storfer-Isser A; Thomas A; Ievers-Landis CE; Redline S. The association of sleep duration with adolescents’ fat and carbohydrate consumption. Sleep, 2010; 33 (9): 1201-1209 

There is now another good reason to exercise. Besides burning calories, exercise restores the sensitivity of neurons involved in the control of satiety (feeling full), which in turn contributes to reduced food intake and consequently weight loss. This is the conclusion of a study led by Brazilian researchers at the University of Campinas, and the findings will be published next week in the online, open access journal PLoS Biology. This disclosure may bring hope to over 40% of the population that suffers from weight problems and obesity around the world.

The increase in obesity has become one of the most important clinical-epidemiological phenomena. Factors such as changing eating habits and a sedentary lifestyle both have a role in the pathogenesis of this disease. It is postulated that excessive consumption of fat creates failures in the signal transmitted by neurons controlling satiety in a region of the brain called the hypothalamus. These failures can lead to uncontrollable food intake and, consequently, obesity.

The group led by José Barreto C. Carvalheira demonstrated that exercising obese rodents showed signals of restored satiety in hypothalamic neurons and decreased food intake. "In obese animals, exercise increased IL-6 and IL-10 protein levels in the hypothalamus, and these molecules were crucial for increasing the sensitivity of the most important hormones, insulin and leptin, which control appetite," Carvalheira explained. Physical activity contributes to the prevention and treatment of obesity, not only by increasing energy expenditure but also by modulating the signals of satiety and reducing food intake.

Physical activity has always been considered a cornerstone in the treatment of obesity, however, only now have the effects of exercise on the control of body weight been understood. Thus, these findings, besides reinforcing the necessity for regular exercise also change the current paradigm established between physical activity and weight loss.

Funding: This study was supported by grants from Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) and Conselho Nacional de desenvolvimento científico e tecnológico (CNPq).

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Journal Reference:

1. Ropelle ER, Flores MB, Cintra DE, Rocha GZ, Pauli JR, et al. IL-6 and IL-10 Anti-Inflammatory Activity Links Exercise to Hypothalamic Insulin and Leptin Sensitivity through IKKb and ER Stress Inhibition. PLoS Biol, 8(8): e1000465 DOI: 10.1371/journal.pbio.1000465