Category: Diet and Weight Loss

Losing weight without a grumbling stomach or expensive liquid diet can be as simple as eating a lighter lunch, finds a new Cornell University study to be published in the October issue of the journal Appetite.

Participants who ate portion-controlled lunches did not compensate by eating more calories later in the day, leading researchers to believe the human body does not possess the mechanisms necessary to notice a small drop in energy intake.

"Making small reductions in energy intake to compensate for the increasing number of calories available in our food environment may help prevent further weight gain, and one way of doing this could be to consume portion-controlled lunches a few times a week," said doctoral student Carly Pacanowski, who co-authored the study with David Levitsky, Cornell professor of nutritional sciences and of psychology.

The study closely monitored the food intake of 17 volunteers who ate whatever they wanted from a buffet for one week. For the next two weeks, half the group selected their lunch by choosing from one of six commercially available, portion-controlled foods, such as Chef Boyardee Pasta or Campbell's Soup at Hand, but could eat as much as they wished at other meals or snacks. For the final two weeks, the other half of volunteers followed the same regimen.

While eating portion-controlled lunches, each participant consumed 250 fewer calories per day and lost, on average, 1.1 pounds.

"The results confirm that humans do not regulate energy intake with any precision. Over a year, such a regimen would result in losing at least 25 pounds," said Levitsky, who adds the study demonstrates one simple, low-cost way to consume fewer calories.

---

Journal Reference:

1. David A. Levitsky, Carly Pacanowski. Losing weight without dieting. Use of commercial foods as meal replacements for lunch produces an extended energy deficit. Appetite, 2011; 57 (2): 311 DOI: 10.1016/j.appet.2011.04.015

 Both marriage and divorce can act as "weight shocks," leading people to add a few extra pounds — especially among those over age 30 — according to a new study. But when it comes to large weight gains, the effects of marital transitions are quite different for men than they are for women.

For men, the risk of a large weight gain increased most prominently after a divorce. But for women, the risk of a large weight gain was most likely after marriage.

"Clearly, the effect of marital transitions on weight changes differs by gender," said Dmitry Tumin, lead author of the study and doctoral student in sociology at Ohio State University.

"Divorces for men and, to some extent, marriages for women promote weight gains that may be large enough to pose a health risk."

The probability of large weight gains following marital transitions increased the most for people past age 30.

"For someone in their mid-20s, there is not much of a difference in the probability of gaining weight between someone who just got married and someone who never married. But later in life, there is much more of a difference," he said.

Tumin conducted the study with Zhenchao Qian, professor of sociology at Ohio State University. They presented their research Aug. 22 in Las Vegas at the annual meeting of the American Sociological Association.

While there have been many studies about weight gain after marriage or divorce, most of them look at average changes in weight and find very small increases in weight after marriage and often small decreases in weight after divorce.

But these results may mask the fact that some people actually lose weight, while some stay the same and some have large weight increases, Qian said.

"We estimated the effects of marital transitions on the likelihood of weight gains or losses for different categories of people, allowing for the possibility that not everyone who goes through a marital transition has the same kind of experience," Qian said.

Tumin and Qian used data from the National Longitudinal Survey of Youth '79, a nationally representative sample of men and women aged 14 to 22 in 1979. The same people were surveyed every year up to 1994 and every other year since then.

In this study, the researchers used data on 10,071 people surveyed from 1986 to 2008 to determine weight gain in the two years following a marriage or divorce.

The NLSY included data on Body Mass Index (BMI), a common health measure of weight relative to height.

The researchers separated people into four groups: those who had a BMI decrease of at least 1 kg/m2 (about 7 pounds for a person 5'10" tall) in the two-year period after a marital transition; those who had a small BMI gain (7-20 pounds for the 5'10" person); a large BMI gain (more than about 21 pounds); or no weight gain or loss (net change of less than 7 pounds).

The researchers took into account a wide variety of other factors that may influence weight gain or loss, including pregnancy for women, poverty, socioeconomic status and education.

Both men and women who married or divorced were more likely than never-married people to have a small weight gain in the two years following their marital transition.

"For most people, the weight gain we see after a marital transition is relatively small, not something we would see as a serious health threat," Tumin said.

However, most other studies have suggested divorce actually leads to weight loss, at least in the first years after the marriage ends. Again, this may be because other studies have not separated people into age and gender groups, and only used average changes in weight, Tumin said.

The data in this study can't reveal why men are more likely to have large weight gains after divorce, while marriage is more likely to cause large weight gains for women.

However, these results fit with other research on how marriage affects men and women.

"Married women often have a larger role around the house than men do, and they may have less time to exercise and stay fit than similar unmarried women," Qian said.

"On the other hand, studies show that married men get a health benefit from marriage, and they lose that benefit once they get divorced, which may lead to their weight gain."

The probability of weight gain become more pronounced for men and women who marry or divorce after age 30 and the changes only grow larger as people get older, the study found.

"From age 22 to 30, the effect of marital transitions on weight is not very clear," Qian said.

"But both marriages and divorces increase the risk of weight changes from about age 30 to 50, and the effect is stronger at later ages."

Tumin said that it may be that people settle into certain patterns of physical activity and diet over time. "As you get older, having a sudden change in your life like a marriage or a divorce is a bigger shock than it would have been when you were younger, and that can really impact your weight."

The researchers noted that this study only looked at people for two years after a marital transition, and results may change over the years.

"This study really looks at the shock of a marital transition and how it affects weight,' Tumin said.

Roux-en-Y gastric bypass, the most common type of bariatric surgery in the United States, is currently considered the most effective therapy for morbid obesity. Patients who undergo this procedure, in which the stomach is reduced to a small pouch and connected to the middle of the small intestine, often lose massive amounts of weight. However, the reasons behind this surgery's success have been unclear. Shedding more light on why this procedure prompts such dramatic weight loss, a team of researchers has found, in a study using both humans and rats, that Roux-en-Y appears to lead patients to significantly reduce their intake of dietary fat. This effect, which was present for both solid and liquid dietary fat, lingered for up to 200 days after surgery in the animals. Further experiments suggest that this fat avoidance is triggered through digestive consequences, rather than just altered taste, and may be the result of an excess of hormones previously linked to food avoidance.

The study appears online in the American Journal of Physiology — Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society.

Methodology

The researchers used data from a study in obese people comparing gastric bypass to vertical-banded gastroplasty. At 1 and 6 years after surgery, these patients were asked to fill out questionnaires that included a series of questions to determine whether they avoided certain foods.

The researchers also performed either Roux-en-Y gastric bypass or sham operations on rats. At time points ranging from 10 to 200 days after surgery, these animals were subjected to various food preference experiments.

In one experiment, the rats were offered either high- or low-fat chow, with the researchers comparing the animals' intake of both foods before and after surgery. Similarly, the rats were presented with bottles containing either water or various concentrations of a fat emulsions, with the researchers recording intake of each liquid. To determine whether taste could be responsible for preference, the researchers recorded how many licks the animals took at each bottle when it was offered for only a brief amount of time.

To determine whether digestive effects instead might be responsible for aversions, rather than taste, the researchers offered the rats water flavored with saccharine, which they typically prefer to unflavored water. They then placed a feeding tube directly into the stomachs of the animals and infused some with corn oil and others with saline solution. Other animals received an injection that causes unpleasant sensations. Previous studies have shown that animals can be conditioned to avoid foods they associate with illness — for example, by avoiding saccharine-flavored water after becoming ill from lithium chloride. Consequently, the researchers reasoned that if corn oil caused unpleasant digestive effects, the rats fed this liquid might also avoid the saccharine-flavored water. Additionally, the researchers tested the levels of GLP-1 and PYY, hormones previously linked with food avoidance, in both the Roux-en-Y and sham-operated animals.

Results

Questionnaires from human patients revealed that those who had gastric bypass were significantly more likely to report a reduction in dietary fat intake compared to those who had gastroplasty instead.

The researchers found that rats who underwent Roux-en-Y surgery consumed significantly lower proportions of high-fat chow and higher proportions of low-fat chow compared to the sham-operated animals. Additionally, those animals who underwent the bypass surgery showed a lower preference for high concentrations of the fat emulsions compared to those who received the sham operation. The Roux-en-Y animals had about the same preference for all concentrations of the fat emulsion when exposed to these liquids for only brief amounts of time. However, those that had a small amount of corn oil infused into their stomach were more likely to avoid the saccharine-flavored water than those infused with saline, much like those given the lithium chloride injections. Levels of GLP-1 were significantly higher in the Roux-en-Y rats compared to the non-bypass animals.

Importance of the Findings

The results suggest that people and animals who undergo Roux-en-Y gastric bypass decrease their consumption of both solid and liquid dietary fat, possibly helping people stick to a healthier diet. This avoidance does not appear to be triggered by taste alone, but can be influenced by the effects after ingestion. The hormone GLP-1 might be partly responsible for these effects.

"These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass," the authors wrote. "By elucidating the mechanisms by which obesity surgery reduces the consumption of high fat foods, new surgical and non-surgical therapies could be developed that mimic these mechanisms to offer safe and effective weight loss."

Study Team

The study team was composed of Carel le Roux, Marco Bueter, Torsten Olbers, Hutan Ashrafian, Thanos Athanasious and Stephen Bloom, all of Imperial Weight Centre, Imperial College London, UK; Nadine Theis, Christian Löwenstein, and Thomas A. Lutz, the Institute of Veterinary Physiology Zurich, Switzerland; Malin Werling, Goteborg University, Goteborg, Sweden; Alan Spector, Department of Psychology, Florida State University, Tallahassee.

---

Journal Reference:

1. Carel W. Le Roux, Marco Bueter, Nadine Theis, Malin Werling, Hutan Ashrafian, Christian Löwenstein, Thanos Athanasiou, Stephen R. Bloom, Alan C. Spector, Torsten Olbers, Thomas Alexander Lutz. Gastric bypass reduces fat intake and preference. American Journal of Physiology — Regulatory, Integrative, and Comparative Physiology, 2011; DOI: 10.%u200B1152/%u200Bajpregu.%u200B00139.%u200B2011

Gastric bypass surgery alters people's food preferences so that they eat less high fat food, according to a new study led by scientists at Imperial College London. The findings, published in the American Journal of Physiology — Regulatory, Integrative, and Comparative Physiology, suggest a new mechanism by which some types of bariatric surgery lead to long-term weight loss.

A growing number of obese patients are choosing to undergo bariatric surgery in order to lose weight, with over 7,000 such procedures being carried out on the NHS in 2009-10. The most common and the most effective procedure is the 'Roux-en-Y' gastric bypass, which involves stapling the stomach to create a small pouch at the top, which is then connected directly to the small intestine, bypassing most of the stomach and the duodenum (the first part of the small intestine). This means that patients feel full sooner.

The new study involved data from human trials as well as experiments using rats. The researchers used data from 16 participants in a study in which obese people were randomly assigned either gastric bypass surgery or another type of operation, vertical-banded gastroplasty, in which the stomach volume is reduced but no part of the intestine is bypassed. The participants who had had gastric bypass had a significantly smaller proportion of fat in their diet six years after surgery, based on questionnaire responses.

In the rat experiments, rats given gastric bypass surgery were compared with rats that were given a sham operation. Rats that had gastric bypass surgery ate less food in total, but they specifically ate less high fat food and more low fat food. When given a choice between two bottles with different concentrations of fat emulsions, the rats that had gastric bypass surgery showed a lower preference for high fat concentrations compared with rats that had a sham operation.

"It seems that people who've undergone gastric bypass surgery are eating the right food without even trying," said Mr Torsten Olbers from Imperial College London, who performed the operations on patients in the study at Sahlgrenska University Hospital in Göteborg, Sweden.

Dr Carel le Roux, from the Imperial Weight Centre at Imperial College London, who led the research, said: "It appears that after bypass surgery, patients become hungry for good food and avoid junk food not because they have to, but because they just don't like it any more. If we can find out why this happens, we might be able to help people to eat more healthily without much effort."

The rat experiments suggested that the reduced preference for high fat food was partly due to the effects of digesting the food. There was no difference in preferences between gastric bypass rats and sham-operated rats when the rats were only given access to the bottles for a few seconds, suggesting that bypass rats did not dislike the taste of high fat emulsions when they were only allowed small volumes at a time.

Rats can learn to avoid foods that they associate with illness, so the researchers tested whether high fat foods would condition them to avoid certain tastes. They gave the rats saccharine-flavoured water while infusing corn oil into their stomachs. The gastric bypass rats learned to avoid saccharine, but the sham-operated rats did not, suggesting that the effect of digesting corn oil was unpleasant to the rats that had had gastric bypass surgery.

Levels of the satiety-promoting hormones GLP-1 and PYY were higher after feeding in the gastric bypass rats compared with sham-operated rats, suggesting a possible mechanism for the changes in food preferences. The team at Imperial plan to study the role of these hormones further to see if it might be possible to mimic the effects of gastric bypass without using surgery.

---

Journal Reference:

1. C. W. Le Roux, M. Bueter, N. Theis, M. Werling, H. Ashrafian, C. Lowenstein, T. Athanasiou, S. R. Bloom, A. C. Spector, T. Olbers, T. A. Lutz. Gastric bypass reduces fat intake and preference. AJP: Regulatory, Integrative and Comparative Physiology, 2011; DOI: 10.1152/ajpregu.00139.2011

Children who are overweight or obese are more likely to be victimised by bullying when compared to children who are not overweight.

The findings, to be presented July 6 at the Annual Scientific Meeting of the Society for Academic Primary Care held at the University of Bristol, explore the prevalence of overweight and obesity in nine-year-olds and its associations with chronic illness and bullying.

Childhood obesity is a major personal, family and public health challenge. Weight problems and obesity in children has increased dramatically throughout Europe in the past two decades. In addition to the increased likelihood of adult obesity with its associated health risks, serious short-term physical and psychosocial consequences endanger the wellbeing of an affected child.

The researchers used a sample of 8,568 nine-year-old children and their families from the first wave of data collection from Growing Up in Ireland — the National Longitudinal Study of Children.

The study found obesity to be more prevalent in girls. In addition children, particularly boys with an abnormal body weight had a significantly higher rate of an ongoing chronic illness.

Children who were overweight or obese were a lot more likely to be victimised by bullying when compared to children who were not overweight.

Dr Udo Reulbach, Clinical Research Fellow in the Department of Public Health and Primary Care & HRB Centre for Primary Care Research, Trinity College Dublin, said: "Previous research has indicated that girls may be more susceptible to overweight and obesity than boys.

"Obesity and overweight are of major concern in Irish children with girls being more affected. It is associated with a higher likelihood of having chronic conditions and being bullied."

Data collection consisted of self-completion surveys with children in school and at home and interviewer administered questionnaires with parents and children in their home. International cut-off points for nine-year-olds for overweight and obesity were used defined to pass through body mass index (BMI) through BMI 25 and 30kg/m2 at age 18 to classify weight categories. Analysis was based on statistically reweighted data to ensure that it is representative of all nine-year-olds in Ireland.

Further research is needed to explore the impact General Practitioners may have in communicating concerns about the weight of a child to parents.

Clinicians may also need to discover the effect of negative weight stereotyping on bullying in children. The much higher rates of overweight and obesity in Irish girls require further investigation and attention.

Obesity has been well established as a leading risk factor for cardiovascular disease, metabolic disease, musculoskeletal disorders, other chronic diseases, some cancers and an overall higher chance of premature death and disability.

In addition to the physical consequences, childhood overweight and obesity is associated with a range of other negative outcomes including poor psychological and educational outcomes and social inequalities.

Synthetic fat substitutes used in low-calorie potato chips and other foods could backfire and contribute to weight gain and obesity, according to a study published by the American Psychological Association.

The study, by researchers at Purdue University, challenges the conventional wisdom that foods made with fat substitutes help with weight loss. "Our research showed that fat substitutes can interfere with the body's ability to regulate food intake, which can lead to inefficient use of calories and weight gain," said Susan E. Swithers, PhD, the lead researcher and a Purdue psychology professor. The study was published online in the APA journal Behavioral Neuroscience.

The study used laboratory rats that were fed either a high-fat or low-fat diet of chow. Half of the rats in each group also were fed potato chips that are high in fat and calories. The remaining rats in each group were fed high-calorie chips on some days and low-calorie chips on other days. The low-calorie chips are made with olestra, a synthetic fat substitute that has zero calories and passes through the body undigested.

For rats on the high-fat diet, the group that ate both types of potato chips consumed more food, gained more weight and developed more fatty tissue than the rats that ate only the high-calorie chips. The fat rats also didn't lose the extra weight even after the potato chips were removed from their diet. "Based on this data, a diet that is low in fat and calories might be a better strategy for weight loss than using fat substitutes," Swithers said. However, she warned that it can be difficult to extrapolate laboratory findings about rats to people, even though their biological responses to food are similar. The study was conducted by Swithers along with Purdue psychology professor Terry L. Davidson, PhD, and former Purdue undergraduate student Sean Ogden.

Why would a fat substitute confuse the body? Food with a sweet or fatty taste usually indicates a large number of calories, and the taste triggers various responses by the body, including salivation, hormonal secretions and metabolic reactions. Fat substitutes can interfere with that relationship when the body expects to receive a large burst of calories but is fooled by a fat substitute.

There is some good news if a diet is naturally low in fat. The rats that were fed a low-fat diet didn't experience significant weight gain from either type of potato chips. However, when those same rats were switched to a high-fat diet, the rats that had eaten both types of potato chips ate more food and gained more weight and body fat than the rats that had eaten only the high-calorie chips.

Swithers and Davidson have reported similar findings in previous rat studies that showed saccharin and other artificial sweeteners also can promote weight gain and increased body fat. The use of artificial sweeteners and fat substitutes has increased dramatically over the past 30 years, mirroring the increase in obesity in America. Dieters have turned to these artificial means to lower calories while still eating foods that taste sweet or fatty. So what is a dieter supposed to do to drop a size?

"Unfortunately, there is no silver bullet," Swithers said. "Eating food which is naturally low in fat and calories may be a better route than relying on fat substitutes or artificial sweeteners."

---

Journal Reference:

1. Susan E. Swithers, Sean B. Ogden and Terry L. Davidson. Fat Substitutes Promote Weight Gain in Rats Consuming High-Fat Diets. Behavioral Neuroscience, 2011; 125 (4)

People generally worry about who their neighbors are, especially neighbors of our children. If high-fat food and soda are nearby, people will imbibe, and consequently gain weight. Or will they? With students' health at risk, a study in the July/August 2011 issue of the Journal of Nutrition Education and Behaviorexplores the influence food store locations near schools has on the student risk of being overweight and student fast-food and sweetened beverage consumption.

Investigators from the University of Southern Maine surveyed 552 students at 11 Maine high schools to determine height, weight, and calorie-dense food consumption of ninth through twelfth grade students. Findings from the study reveal that half of the students consumed soda at least once a week and just over 10% consumed it daily, with a slightly smaller number consuming sports drinks in these time periods. In addition, nearly two thirds had visited a burger and fries fast food restaurant in the previous month, whereas over half had visited a pizza parlor during that period. Of the 552 students surveyed, one quarter of students were overweight (12.7%) or obese (12.5%), whereas 73% were of normal weight and 1.8% were underweight.

Surprisingly, this study found no correlation between students' overweight risk and the presence of stores with unhealthful food choices near their schools. Dr. David E. Harris, Professor at University of Southern Maine, states, "This study reports that the consumption of sweetened drinks and fast food among Maine high school students is high. One-half consumed sweetened soda weekly, and over two-thirds consumed fast food monthly, and students access these food items at a myriad of different locations. However, the proximity or density of stores with unhealthful food near Maine high schools does not predict the risk of overweight for students at these schools. This finding suggests that high school nutrition programs that focus on student behavior may be more effective than programs that focus on the built food environment near the school, at least in a predominantly nonurban setting such as Maine."

This study documents the importance of identifying determinants that influence adolescents' risk of being overweight. The researchers emphasize that "until unhealthful food choices are reduced overall, it is not surprising that the presence of food stores near their schools has little impact on students' risk of being overweight."

---

Journal Reference:

1. David E. Harris, Janet Whatley Blum, Matthew Bampton, Liam M. O'Brien, Christina M. Beaudoin, Michele Polacsek, Karen A. O'Rourke. Location of Food Stores Near Schools Does Not Predict the Weight Status of Maine High School Students. Journal of Nutrition Education and Behavior, Volume 43, Issue 4 (July/August 2011)

Following a low-saturated fat and low-glycemic index diet appears to modulate the risk of developing dementia that proceeds to Alzheimer's disease (AD), and making a switch to this dietary pattern may provide some benefit to those who are experiencing cognitive difficulty, according to a report in the June issue of Archives of Neurology, one of the JAMA/Archives journals.

Previous research has suggested multiple links between diet and cognitive ability, the authors note as background information. Health conditions in which insulin resistance (the body's inability to use insulin effectively) is a factor — obesity, type 2 diabetes, cardiovascular disease and high cholesterol levels — have also been associated with "pathological brain aging." However, studies of specific foods have not found conclusive evidence of an influence on Alzheimer's risk. "Thus," the authors write, "a more promising approach to the study of dietary factors in AD might entail the use of whole-diet interventions, which have greater ecologic validity and preserve the nutritional milieu in which fat and carbohydrate consumption occurs."

Jennifer L. Bayer-Carter, M.S., from Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues sought to compare a high-saturated fat/high-simple carbohydrate diet (a macronutrient pattern associated with type 2 diabetes and insulin resistance) with a low-saturated fat/low-simple carbohydrate diet; the interventions were named HIGH and LOW, respectively. The authors evaluated the effects of these diets in 20 older adults who were healthy and 29 older adults who had amnestic mild cognitive impairment (aMCI), meaning they experienced some memory problems; the latter condition is often considered a precursor to AD. In a four-week randomized, controlled trial, 24 participants followed the HIGH diet and 25 followed the LOW diet. The researchers studied participants' performance on memory tests as well as their levels of biomarkers (biological substances indicative of AD), such as insulin, cholesterol, blood glucose levels, blood lipid levels and components of cerebrospinal fluid (CSF).

Results of the study were different for the group that had aMCI and the group of healthy participants. In the latter group, the LOW diet decreased some CSF biomarkers of AD as well as total cholesterol levels. However, among individuals with aMCI, the LOW diet increased levels of these biomarkers. Some changes to biomarkers, such as CSF insulin levels, were observed in both groups. Additionally, the LOW diet improved performance on delayed visual recall tests for both healthy and memory-impaired participants, but did not affect scores on other cognitive measures.

The findings indicate that "for healthy adults, the HIGH diet moved CSF biomarkers in a direction that may characterize a presymptomatic stage of AD," explain the authors. They believe that the different results of the unhealthy diet in participants with aMCI may be due to the diet's short duration. "The therapeutic effects of longer-term dietary intervention may be a promising avenue of exploration," the authors conclude. "In addition, identification of the pathophysiologic changes underlying dietary effects may reveal important therapeutic targets that can be modulated through targeted dietary or pharmacologic intervention."

---

Journal Reference:

1. Jennifer L. Bayer-Carter; Pattie S. Green; Thomas J. Montine; Brian VanFossen; Laura D. Baker; G. Stennis Watson; Laura M. Bonner; Maureen Callaghan; James B. Leverenz; Brooke K. Walter; Elaine Tsai; Stephen R. Plymate; Nadia Postupna; Charles W. Wilkinson; Jing Zhang; Johanna Lampe; Steven E. Kahn; Suzanne Craft. Diet Intervention and Cerebrospinal Fluid Biomarkers in Amnestic Mild Cognitive Impairment. Archives of Neurology, 2011; 68 (6): 743-752 DOI: 10.1001/archneurol.2011.125

 Adolescent girls whose diet resembles one recommended for adults with hypertension appear to have smaller gains in overall body mass index (BMI) over 10 years, according to a report in the June issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals.

"Excess weight during childhood leads to numerous health problems and is even associated with premature death as an adult," the authors write as background information in the article. However, the authors note that examinations of food-based dietary patterns acknowledge that consuming various nutrients together can have positive influences on health. One such diet pattern, the Dietary Approach to Stop Hypertension (DASH), was originally studied as a treatment for adults with hypertension, according to background in the article.

Jonathan P. B. Berz, M.D., M.Sc., of Boston University Medical Center, and colleagues evaluated the effects of a DASH-style eating plan on BMI (calculated as weight in kilograms divided by height in meters squared) in a racially diverse sample of adolescent girls. The authors examined data from 2,237 girls 9 years of age who participated in the National Growth and Health Study from 1987-1988 and were followed up for 10 years. Data were gathered annually and each participant was given a DASH food group score based on individual adherence to dietary requirements.

Higher DASH scores were associated with higher total energy intake, as well as higher average intake from each food group (whole grains, vegetables, fruits, lean meats, low-fat dairy and nuts/seeds/legumes). Girls in the highest quintile of DASH scores had the smallest gains in BMI during the study, and had the lowest BMIs at the end of follow-up. Conversely, at age 19 years, girls in the lowest DASH score quintile had an average BMI that was greater than the threshold for overweight as defined by the 85th percentile for age.

"In particular, higher consumption of fruits, whole grains and low-fat dairy products led to less weight gain," the authors noted. Participants who consumed two or more servings of fruit per day had the smallest gains in BMI during the study years and had the lowest BMI at the end of follow-up. Compared with participants consuming the least amount of whole grains, those who consumed the most had lower BMI scores over time and a lower BMI at the end of follow-up. The same results were seen for girls consuming higher amounts of low-fat dairy products.

"We found that higher adherence to a DASH-style diet resulted in a consistently lower BMI between the ages of 9 and 19 years," the authors conclude. "Such an eating pattern may help prevent excess weight gain during adolescence."

Editorial: The DASH Diet Predicts Weight Gain

In an accompanying editorial, Robert C. Klesges, Ph.D. and Marion Hare, M.D., of the University of Tennessee Health Science Center, Memphis, Tenn., comment on the findings of this study. "As Berz et al point out, the DASH diet has been well validated in adults, and there is absolutely no reason for it to not work in children," they write. "The DASH diet is flexible and should meet the food preferences of most children. However, interventions for children need to be simplified; therefore, it make sense to specifically recommend increased consumption of fruits and low-fat dairy products."

"In summary, Berz et al add to a growing body of literature that will eventually help us to understand and hopefully treat pediatric obesity. A logical step in this literature is to test the DASH diet in children along with other efficacious adult obesity interventions."

---

Journal References:

1. J. P. B. Berz, M. R. Singer, X. Guo, S. R. Daniels, L. L. Moore. Use of a DASH Food Group Score to Predict Excess Weight Gain in Adolescent Girls in the National Growth and Health Study. Archives of Pediatrics and Adolescent Medicine, 2011; 165 (6): 540 DOI: 10.1001/archpediatrics.2011.71
2. R. C. Klesges, M. Hare. The DASH Diet Predicts Weight Gain: What Does This Mean for My Pediatric Practice?Archives of Pediatrics and Adolescent Medicine, 2011; 165 (6): 567 DOI: 10.1001/archpediatrics.2011.62

 A new study presented at SNM's 58th Annual Meeting could throw open the door to a recently established area of obesity research. Investigators have developed a novel molecular imaging agent that targets estrogenic mechanisms in the brain to find out what effect an enzyme called aromatase has on body mass index (BMI), a measurement of body fat based on height and weight. Aromatase is crucial for the production of estrogen in tissues throughout the body, including the brain.

According to the World Health Organization, worldwide obesity has more than doubled since 1980. As of 2008, an estimated 1.5 billion adults were overweight, and in 2010 nearly 43 million children under the age of five were overweight.

"We used this imaging agent to evaluate the amount of aromatase activity in the brain regions related to eating behaviors, such as the hypothalamus and amygdala, in both overweight and normal weight subjects. We were really surprised to see the highest correlation between aromatase availability and BMI happening in the amygdala, which controls emotional memory," says Gene-Jack Wang, MD, senior scientist and chair of the medical department at Brookhaven National Laboratory, Upton, N.Y. "Our eating is not only controlled by the hunger centers in the brain. It is also related to memory, and that could have a big impact on a person's eating behavior. This agent could potentially translate into a number of new studies evaluating estrogen and obesity, food intake and appetite suppression."

For this study, five healthy overweight subjects and 13 normal-weight subjects of the same age were chosen to undergo positron emission tomography, a molecular imaging technique that provides digital representations of physiological functions of the body. Subjects were injected before imaging with the novel imaging agent (C-11)vorozole, which is composed of a medical isotope bound with an aromatase inhibitor that binds strongly with the active sites of the enzyme in the brain. This allowed investigators to track and quantify the availability of this enzyme to selected areas of the brain associated with hunger and feeding behavior.

A significant correlation was found between high BMI of subjects and decreased uptake of the aromatase inhibitor. Imaging agent uptake was decreased in the hypothalamus (25 percent less), thalamus (27 percent less) and amygdala (30 percent less) in subjects with high BMI. This means that there was less availability of the enzyme in these selected brain regions. There was also a strong inverse correlation between low BMI and imaging agent uptake in the amygdala, meaning BMI was less in subjects showing higher aromatase availability. These findings suggest that there is decreased availability of aromatase in the brains of overweight subjects, conceivably leading to reduced availability of estrogen and potentially less control over appetite and food intake, resulting in weight gain; however, further studies need to be conducted to validate the relationship between estrogen synthesis and high BMI.

Future studies could be introduced to screen eating behaviors of obese subjects in order to further validate the correlation between BMI and estrogen availability in the brain. Based on the current research, theoretically the less estrogen available to the brain, the less control patients may have over their appetite. Studies moderating estrogen and feeding behavior could result in novel drugs for appetite suppression and perhaps even reduction of BMI. This is just the first step toward discovering the mechanisms behind appetite, BMI and estrogen availability.