MedicalResearch.com Interview with:
Peter Würtz, PhD, Docent
Head of Molecular Epidemiology, Computational Medicine,
Institute of Health Sciences, University of Oulu, Finland
Medical Research: What is the background for this study? What are the main findings?Dr. Würtz: Obesity is linked with unfavorable cholesterol and blood sugar levels, but the fine-grained metabolic consequences of excess body weight remain unclear. We used a novel profiling technology developed in our research group to examine the metabolic consequences of excess body weight. We profiled over 12,000 healthy young volunteers from the general population to determine the detailed metabolic effects of having higher BMI (body mass index). We found that higher BMI is causing adverse metabolic changes in the blood levels of many amino acids and lipids, as well as an altered balance of omega-fatty acids and sex hormones. These measures have been linked with higher risk for developing heart disease and type 2 diabetes. Importantly, the metabolic deviations were not limited to obese individuals, but were observed in a continuous manner including for those who are lean or overweight. In other words, the metabolic profile becomes more adverse for any increase in BMI, with no threshold below which an increase in BMI would not affect the cardiometabolic risk profile. Genetic information was used to demonstrate that the metabolic effects are actually caused by having higher BMI. On the positive side, even a modest weight loss helped to diminish the adverse metabolic influences of excess body fat.
MedicalResearch.com Interview with:
Marcus Munafò PhD
Professor of Biological Psychology
MRC Integrative Epidemiology Unit
UK Centre for Tobacco and Alcohol Studies
School of Experimental Psychology
University of Bristol United Kingdom
Medical Research: What is the background for this study? What are the main findings?Dr. Munafo: We were conducting an analysis of data on smoking behaviour and body mass index (BMI), in order to better understand the potential causal effects of smoking on different measures of adiposity. Mendelian randomisation uses genetic variants associated with the exposure of interest (in this case smoking) as proxies for the exposure, in order to reduce the risk of spurious associations arising from confounding or reverse causality. As expected, we found that, among current smokers, a genetic variant associated with heavier smoking was associated with lower BMI, providing good evidence that smoking reduces BMI. However, we also unexpectedly found that the same variant was associated with higher BMI in never smokers. This suggests that this variant might be influencing BMI via pathways other than smoking.
MedicalResearch.com Interview with:Stefan Johansson, MD PhD
Medical Research:What is the background for this study?Dr. Johansson: Maternal obesity (BMI ≥ 30) has previously been linked to increased infant mortality. However, research has not produced consistent results. For example, there are disagreements whether infants to overweight mothers (BMI 25-29) are at increased risk, and research on BMI-related specific causes of death is scarce.
MedicalResearch.com Interview with:
Nicolas Cherbuin PhD
ARC Future Fellow - Director of the NeuroImaging and Brain Lab
Centre for Research on Ageing, Health and Wellbeing
Research School of Population Health - College of Medicine Biology and Environment
Australian National University
Medical Research:What is the background for this study? What are the main findings?Dr. Cherbuin: A number of modifiable risk factors for cognitive aging dementia and Alzheimer’s disease have been identified with a high level of confidence by combining evidence from animal research and systematic reviews of the literature in humans that summarise the available findings without focusing on extreme findings that come about from time to time in research. One such risk factor is obesity for which we have previously conducted a systematic review (Anstey et al. 2011). This showed that obesity is associated with a two-fold increased risk of dementia and a 60% increased risk of Alzheimer’s disease. What was surprising is that this effect was only detectable for obesity in middle age but not old age. This might suggest that the obesity only has an adverse effects on brain health earlier in life and that this effect fades at older ages. This is unlikely because a number of animal studies have shown that the biological mechanisms linking obesity with brain pathology do not disappear with older age but in fact appear to increase. Moreover, human studies show that thinking abilities decline faster in obese individuals. An alternative explanation is that human epidemiological studies investigating this question in older individuals include participants who do not have clinical dementia but in whom the disease is developing. Since dementia and Alzheimer’s disease pathology is associated with weight loss it is possible that estimated effects in humans have been confounded by this issue. Another possible confounder is that older people tend to lose muscle mass (sarcopenia) this may lead to the paradoxical condition in aging where a person has a normal weight but has excessive fat mass. Since it is fat tissue that is linked to risk to cerebral health it may have led to the apparently contradictory findings that obesity may not be a risk in older age. It is therefore of great interest to clarify whether obesity in early old age in individuals free of dementia is associated with poorer cerebral health. The hippocampus is one of the structures most sensitive stressors. Because obesity is known to lead to a state of chronic inflammation which is deleterious to the hippocampus, it was a logical structure to investigate. Moreover, the hippocampus is needed for memory function and mood regulation and is directly implicated in the dementia disease process.
This study investigated 420 participants in their early 60s taking part in a larger longitudinal study of aging taking place in Canberra, Australia and who underwent up to three brain scans over an 8-year follow-up. These individuals were free of dementia and other neurological disorders. Associations between obesity and shrinkage of the hippocampus were investigated with longitudinal analyses which controlled for major confounders.
The main findings were that overweight and obese participants had smaller volume of the hippocampus at the start of the study. In addition, the hippocampus shrunk more in these individuals over the follow-up period.
MedicalResearch.com Interview with:James J. DiNicolantonio, PharmD
Associate Editor BMJ Open Heart
Cardiovascular Research Scientist
Saint Luke's Mid America Heart Institute
Medical Research:What is the background for this study? What are the main findings?Dr. DiNicolantonio: Focusing on calories misdirects eating away from healthy foods (that are higher in calories - such as nuts, salmon, and avocados) and towards harmful foods (e.g. rapidly absorbable carbohydrates - including added sugars such as table sugar and high fructose corn syrup).
Treating obesity should not focus on decreasing caloric intake, rather, it should focus on eating quality foods. Lower calorie foods - that are high in rapidly absorbable carbohydrates - drive increased hunger throughout the day, whereas higher calorie foods (such as full-fat milk and eggs) leads to satiety. Consuming rapidly absorbable carbohydrates leads to increased total caloric intake throughout the day (driven by insulin resistance and leptin resistance). These metabolic consequences derived from overconsuming these types of foods leads us to eat more and exercise less. In essence, eating more and exercising less doesn't cause obesity, overconsuming rapidly absorbable carbohydrates causes us to eat more and exercise less, which then causes obesity - a subtle but important distinction.
MedicalResearch.com Interview with:
Stephen D. Ginsberg, Ph.D., Associate Professor
Departments of Psychiatry and Physiology & Neuroscience
New York University Langone Medical Center
Center for Dementia Research
Nathan Kline Institute Orangeburg, NY 10962
Medical Research:What is the background for this study? What are the main findings?Dr. Ginsberg: We tested the hypothesis that long-term calorie restriction positively alters gene expression within the hippocampus, a critical learning and memory area vulnerable in aging and Alzheimer’s disease. To test this hypothesis, we conducted experiments on female mice that were given food pellets 30% lower in calories than what was fed to the control group. The mice ate fewer calories derived from carbohydrates. Analyses were performed on mice in middle and old age to assess any differences in gene expression over time. Our data analysis revealed that the mice that were fed a lower calorie diet had fewer changes in approximately 900 genes that are linked to aging and memory. (more…)
MedicalResearch.com Interview with:
Michele D. Levine Ph.D.
Associate Professor of Psychiatry and PsychologyWestern Psychiatric Institute and Clinic
Department of Statistics, University of Pittsburgh, Pittsburgh PA
Medical Research:What is the background for this study? What are the main findings?Dr. Levine: Many women quit smoking as a result of pregnancy. However, psychiatric disorders, which are prevalent among smokers can contribute to weight gain. Thus, we sought to examine the relationship between maternal psychiatric disorders and gestational weight gain in a sample of pregnant former smokers. Results from the present study demonstrate that the rates of psychiatric disorders were high among pregnant former smokers and that more than half of women gained more weight than recommended by the IOM. Although a history of having had any psychiatric disorder was not associated with gestational weight gain, a history of alcohol use disorder specifically was positively related to gestational weight gain.
MedicalResearch.com Interview with:
Hanna Konttinen, PhD, Docent
Department of Social Research
University of Helsinki
Medical Research:What is the background for this study?Dr. Konttinen: Bariatric surgery yields significant weight reduction for the majority
of severely obese individuals with accompanied improvements in health
status and health-related quality of life. Nonetheless, slow weight
regain over time is frequent and there is a need for a better
understanding on the factors that influence long-term post-surgical
weight outcomes. To our best knowledge, this was the first study to
examine whether psychological aspects of eating behavior predicted
weight changes 10 years after surgical and conventional treatment for
The participants were from the Swedish Obese Subjects intervention
study: 2010 obese subjects who underwent bariatric surgery and 1916
contemporaneously matched obese controls who received conventional
MedicalResearch.com Interview with:
Yvonne M. Terry-McElrath, MSA
Research Associate, Survey Research Center, Institute of Social Research
University of Michigan Tobacco Research Center
Medical Research: What is the background for this study? What are the main findings?Dr. Terry-McElrath: The United States Department of Agriculture (USDA) recently improved nutrition standards for federally-reimbursable school lunch and breakfast programs. Most lunch standards were implemented at the beginning of the 2012-13 school year and changes in breakfast began with the 2013-14 school year. Beginning in 2014, schools participating in federally-reimbursable meal programs were also required to improve nutrition standards for foods and beverages sold in vending machines, stores/snack bars/carts, and à la carte cafeteria lines. The new standards limit fats, sodium, sugar, and calories; and will eventually remove candy; regular-fat salty snacks/sugary treats; higher-fat milks; high-fat, high-calorie savory foods; and sugar-sweetened beverages, like regular soda, fruit drinks and high calorie sports drinks. They were developed in response to rising overweight/obesity among US children and adolescents.
This study uses five years of data from nationally-representative samples of middle and high school students—and their school administrators—to examine three research questions: What percentage of US secondary students attended schools in 2008-2012 where foods and beverages met at least some of the USDA standards that were to begin phased implementation starting in 2012-13? Is there evidence that those standards were associated with student overweight/obesity? Is there evidence of the effect of those standards on racial/ethnic minorities and students from lower income families? Using data from schools even before the new USDA standards went into effect can indicate potential effect of the standards once they have been in effect for several years. The research was conducted through two studies: The Monitoring the Future study, supported by a grant from the National Institute on Drug Abuse, and the Youth, Education and Society study, part of a larger research initiative funded by the Robert Wood Johnson Foundation, titled “Bridging the Gap: Research Informing Policy and Practice for Healthy Youth Behavior.”
Study findings show that from 2008-2012, few middle or high school students attended schools where food and beverage standards would be judged to meet at least some of the USDA school nutrition standards that began to be implemented in 2012-13. Significant increases in the number of standards over time were seen for middle but not high school students. Among high school students, having fruits and vegetables available wherever foods were sold, the absence of higher-fat milks, and increasing the number of positive nutrition standards were associated with significantly lower odds of overweight/obesity. Not having sugar-sweetened beverages was associated with lower overweight/obesity for middle and high school minority students.
MedicalResearch.com Interview with: Ian R. Macumber MD
Pediatric Nephrology, Seattle Children's Hospital
Medical Research: What are the main findings of the study?Dr. Macumber: The main finding is that there is a strong association between maternal obesity and odds of congenital anomalies of the kidney and urinary tract (CAKUT) in offspring. This relationship remains strong when looking at offspring with renal malformation (excluding non-renal congenital anomalies of the kidney and urinary tract), or in offspring with isolated congenital anomalies of the kidney and urinary tract (no congenital anomalies elsewhere in the body). There is a dose-response relationship to this association, with the offspring of extremely obese mothers have even higher odds of having congenital anomalies of the kidney and urinary tract.
MedicalResearch.com Interview with:Gang Hu, MD, MPH, PhD, FAHA
Assistant professor & Director
Chronic Disease Epidemiology Lab
Adjunct assistant professor, School of Public Health
LSU Health Sciences Center
Pennington Biomedical Research Center,
Baton Rouge, Louisiana
Medical Research: What is the background for this study? What are the main findings? Dr. Hu: Many previous studies had small samples, and thus lacked adequate statistical power when the analysis was focused on those who are extremely obese (BMI ≥40 kg/m2). In addition, most epidemiological studies only use a single measurement of BMI at baseline to predict risk of all-cause mortality, which may produce potential bias. The current study indicated a U-shaped association of BMI with all-cause mortality risk among African American and white patients with type 2 diabetes. A significantly increased risk of all-cause mortality was observed among African Americans with BMI<30 kg/m2 and BMI ≥35 kg/m2, and among whites with BMI<25 kg/m2 and BMI ≥40 kg/m2 compared with patients with BMI 30-34.9 kg/m2.
MedicalResearch.com Interview with: Venkatesh L. Murthy, MD, PhDDepartment of Medicine (Cardiovascular Medicine Division) and Department of Radiology (Nuclear Medicine and Cardiothoracic Imaging Divisions),
University of Michigan, Ann Arbor, Michigan andDr. Ravi Shah MD
Cardiology Division, Department of Medicine
Massachusetts General Hospital, Boston, MassachusettsMedical Research: What is the background for this study? What are the main findings?Response: Prior studies in Framingham, MESA and other cohorts have demonstrated that obesity is an important risk factor for the metabolic syndrome. However, the observations that many non-obese individuals develop metabolic syndrome and diabetes and, conversely, that not all obese individuals develop these complications has motivated the search for better markers of risk than BMI. More recently, it has been shown that the location of adipose tissue is an important factor. The amount of visceral fat, which is thought to be more harmful from a metabolic perspective, can be accurately quantified with CT imaging. In many prior studies, waist circumference has been used as an approximate measure of visceral adiposity.
For this study, we analyzed data from the Multi-Ethnic Study of Atherosclerosis (MESA). We found that the amount of visceral fat (as quantified by CT) was an important predictor of metabolic syndrome, even after adjusting for weight, waist circumference, gender, race, smoking, exercise, serum lipids and glucose. Each additional 100 cm2/m of height of visceral fat was associated with a 29% increase in the risk of developing metabolic syndrome. In contrast, subcutaneous fat burden (also quantified by CT) was a much weaker predictor.
One of the very novel findings of our study arises from an analysis of subjects who had multiple CTs longitudinally in MESA. Using these data, we found that change in visceral fat burden was associated with a corresponding 5% increase in the risk of metabolic syndrome. In part, this is because very small changes in weight could result in very large changes in visceral fat.
MedicalResearch.com Interview with:
Angela Alberga, PhD
Eyes High Postdoctoral Fellow
Werklund School of Education
University of CalgaryRonald J. Sigal, MD, MPH, FRCPC
Professor of Medicine, Kinesiology, Cardiac Sciences and Community Health Sciences
Division of Endocrinology and Metabolism, Cumming School of Medicine, University of Calgary
Health Senior Scholar, Alberta Innovates-Health Solutions
Member, O'Brien Institute of Public Health, Libin Cardiovascular Institute and Julia McFarlane Diabetes Research CentreMedical Research: What are the main findings of the study?Response: The Healthy Eating, Aerobic and Resistance Training in Youth study examined the effects of exercise on body composition and cardiometabolic risk markers in adolescents with obesity. A total of 304 overweight or obese adolescents were randomized to four groups. The first group performed resistance training involving weight machines and some free weights; the second performed only aerobic exercise on treadmills, elliptical machines and stationary bikes; the third underwent combined aerobic and resistance training; and the last group did no exercise training. All four groups received nutritional counseling. In analyses involving all participants regardless of adherence, each exercise program reduced percent body fat, waist circumference and body mass index to a similar extent, while the diet-only control group had no changes in these variables. In participants who exercised at least 2.8 times per week, we found that combined aerobic and resistance training produced greater decreases in percentage body fat, waist circumference, and body mass index than aerobic training alone. Waist circumference decreased close to seven centimeters in adherent participants randomized to combined aerobic plus resistance exercise, versus about four centimeters in those randomized to do just one type of exercise, with no change in those randomized to diet alone.
MedicalResearch.com Interview Invitation Dr Ken Ong, Programme Leader & Paediatric Endocrinologist
MRC Epidemiology Unit, University of Cambridge
Box 285 Institute of Metabolic Science
Cambridge Biomedical Campus, Cambridge
Medical Research: What are the main findings of this report?Dr. Ong: We found that genetic factors that predict adult obesity were associated with faster weight gain and growth during infancy – the findings indicate that the biological mechanisms that predispose to later obesity are already active from birth.
MedicalResearch.com Interview with Dr. Michelle Lent PhD
Geisinger Health System
Medical Research: What is the background for this study?Dr. Lent:Previous study findings indicate that weight bias relates to a number of adverse outcomes in overweight and obese populations, including binge eating, psychological disorders and body image issues. In this study, we measured the degree to which people undergoing weight-loss surgery translate “anti-fat” attitudes into negative beliefs about themselves before surgery (known as “internalized weight bias”) and if this influences weight loss outcomes after surgery. (more…)
MedicalResearch.com Interview with: Deborah Clegg, PhD
Research Scientist, Diabetes and Obesity Research Institute
Associate Professor, Department of Biomedical Science
Cedars-Sinai Medical Center
Los Angeles, CA 90048
Medical Research: What are the main findings of the study?Dr. Clegg:The main findings are that males and females differ with respect to how they process and respond to diets high in fat!!!! Males following consumption of a diet that is 42% of the calories coming from saturated fat (it would be analogous to eating a big mac and having a coke), gained the same amount of weight as did the females BUT the males had increased markers of inflammation in their brains and the females did not. With the elevated markers of inflammation, the males had dysregulation in glucose homeostasis and alteration in cardiovascular function – yet the females did not!!
MedicalResearch.com Interview with:
Donna Tepper, M.D.
Henry Ford Hospital
Medical Research: What are the main findings of the study?Dr. Tepper:We looked at 94 patients who underwent bariatric surgery at Henry Ford from 2003 through 2013. Of those, 47 subsequently had body recontouring procedures, such as body lift, abdominoplasty (tummy tuck), arm lift, thigh lift, face lift. We recorded the patients’ body mass index prior to bariatric surgery, and then again at 6 months, 1, 2.5, 4, and 5 years. Of the patients who underwent contouring surgery, the average decrease in BMI was 18.24 at 2.5 years, compared to a statistically significant 12.45 at 2.5 years for those who did not have further surgery. This is statistically significant. This 3 point change in BMI is an 18-21 pound difference depending on patient height. Furthermore, the BMI in the body contouring group continues to be lower at 4 and 5 years from bariatric surgery compared to the bariatric surgery alone group. (more…)
MedicalResearch.com Interview with: Anita P. Courcoulas M.D., M.P.H., F.A.C.S
Professor of Surgery
Director, Minimally Invasive Bariatric & General Surgery
University of Pittsburgh Medical Center
Medical Research: What are the main findings of the study?Dr. Courcoulas: This paper was not a study but a summary of findings from a multidisciplinary workshop (and not a consensus panel) convened in May 2013 by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Heart, Lung, and Blood Institute. The goal of the workshop was to summarize the current state of knowledge of bariatric surgery, review research findings on the long-term outcomes of bariatric surgery, and establish priorities for future research.
MedicalResearch.com Interview with:Professor Usha Menon, Evangelia-Ourania FourkalaPhD
and Matthew Burrell PhD
Gynaecological Cancer Research Centre, Women's Cancer, UCL EGA
Institute for Women's Health, University College London, UK
Medical Research: What are the main findings of the study?Response: Our study has shown that skirt size is a good proxy for central obesity. Each unit increase in UK skirt size every ten years between the age of 20 and 60 was associated with a 33% increase in postmenopausal breast cancer in our cohort.
MedicalResearch.com Interview with: Stewart Agras, M.D.
Professor of Psychiatry Emeritus
Stanford University School of Medicine
MedicalResearch: What was the study about?
Dr. Agras: Family-based treatment (FBT) has been shown to be more effective than individual psychotherapy for the treatment of adolescent anorexia nervosa. This treatment focuses on helping the family to re-feed their child. The question posed in this study was whether Family-based treatment would have any advantages over Systemic family therapy (SyFT) focusing on family interactions that may affect the maintenance of the disorder. The participants were 164 adolescents with anorexia nervosa and their families – one of the largest studies of its type.
MedicalResearch.com Interview with: Tuomo Tompuri, MD
Clinical Physiology and Nuclear Medicine
Kuopio University Hospital, Finland
Medical Research: What are the main findings of the study?Dr. Tompuri: Measures of the cardiorespiratory fitness should be scaled by lean mass instead of body weight, while aiming to enable comparison between the subjects. Our result is physiologically logical and confirms earlier observations of the topic. Scaling by body weight has been criticized, because body fat, per se, does not increase metabolism during exercise. We did observe that scaling by body weight introduces confounding by adiposity.
MedicalResearch.com Interview with:Dr. Holly R. Wyatt, MD
Endocrine Society spokeswoman
Associate Professor, University of Colorado Denver
Medical Director, Anschutz Health and Wellness Center
Medical Director, ABC’s TV series “Extreme Weight Loss”.
MedicalResearch.com Editor’s note: Dr. Wyatt is a nationally known expert on obesity and weight control. Dr. Wyatt is co-founder of ‘The State of Slim’ behavioral weight management program and has been the National Program Director for the Centers for Obesity Research and Education (C.O.R.E.) since 1999. Dr. Wyatt publishes extensively in the obesity and metabolism literature including publications in the NEJM, Obesity, Annals of Internal Medicine, Journal of Clinical Endocrinology & Metabolism and American Journal of Clinical Nutrition among others. Dr. Wyatt kindly answered questions regarding weight loss and maintenance for the MedicalResearch.com audience.
Medical Research: How did you become interested in weight control?Dr. Wyatt: Basically, because I struggled with my weight all my life. I was always planning on going to medical school and had been interested in learning more about the science of weight gain and metabolism, but at the time the subject was not well studied. When I came to the University of Colorado for my medical residency, I met researchers who were investigating the growing problem of obesity and were passionate about finding effective strategies for weight management. I have been active in clinical practice and obesity research since that time.
Medical Research: Why does weight loss or even weight maintenance become so much harder as we age?
Dr. Wyatt: We don’t know all the reasons for certain, but the problem is most likely multifactorial.
First, as we age we lose muscle mass. To a large degree, muscle mass determines our metabolic rate so even if our body weight stays stable, our metabolic engine slows down as we lose muscle and it becomes harder to maintain that weight.
Secondly, there is some role with for hormonal changes, but this role is incompletely understood. With menopause we tend to store weight centrally in our bodies, which may be a hormonal effect.
Perhaps most importantly, life changes as we get older and our lifestyle and environment evolves. We may not realize how much these changes affect the amount of energy we burn as our environment become more sedentary and obesogenic.
I should also point out that it is harder for everyone in our society to avoid gaining weight, even for children. Increasing numbers of children and adolescents are overweight and fighting obesity.
MedicalResearch.com Interview with: Aner Tal, PhD
Food and Brand Lab
Department of Applied Economics and Management
Cornell University, Ithaca, New York
Medical Research: What are the main findings of the study?Dr. Tal:Some TV programs might lead people to eat twice as much as other programs.
“We find that if you’re watching an action movie while snacking your mouth will see more action too!” says Aner Tal, Ph.D. lead author on the new article just published in the Journal of the American Medical Association: Internal Medicine. “In other words, the more distracting the program is the more you will eat.” In the study 94 undergraduates snacked on M&Ms, cookies, carrots and grapes while watching 20 minutes of television programming. A third of the participants watched a segment of the action movie The Island, a third watched a segment from the talk show, the Charlie Rose Show, and a third watched the same segment from The Island without sound. “People who were watching The Island ate almost twice as many snacks – 98% more than those watching the talk show!” says co-author Brian Wansink, author of Slim by Design (forthcoming) and Professor and Director of the Cornell Food and Brand Lab. “Even those watching “The Island” without sound ate 36% more.” People watching the more distracting content also consumed more calories, with 354 calories consumed by those watching The Island (314 calories with no sound) compared to 215 calories consumed by those watching the Charlie Rose Show. “More stimulating programs that are fast paced, include many camera cuts, really draw you in and distract you from what you are eating. They can make you eat more because you're paying less attention to how much you are putting in your mouth,” explains Tal. Because of this, programs that engage viewers more might wind up being worse for their diets.
MedicalResearch.com Interview with:Alison M Gallagher PhD FHEA RNutr (Public Health)
Senior Lecturer in Human Nutrition
Northern Ireland Centre for Food and Health (NICHE)
School of Biomedical Sciences
University of Ulster Northern Ireland, UK
Medical Research: What are the main findings of the study?Dr. Gallagher: The main findings of the study were that overweight and obese males appeared to be more aware of food related images as compared to their normal weight counterparts. Individuals, regardless of weight status also appeared to be more visually ‘tuned in’ to high energy dense food-related visual stimuli as compared to low energy dense food-related stimuli. As high energy dense foods are overtly represented within the visual environment through food advertising, it may be of particular concern if certain individuals, in particular those who are overweight/obese, are demonstrating increased attention (an attentional bias) towards high energy dense food stimuli.
MedicalResearch.com Interview with: Earl S. Ford, MD, MPH
Medical officer, U.S Public Health Service
Centers for Disease Control and Prevention
Atlanta, GA 30341
Medical Research: What are the main findings of the study?Dr. Ford: The main finding of the study is that mean waist circumference and the prevalence of abdominal obesity in US adults have increased since 1999-2000 and that these increases are being driven primarily by trends in women. Mean waist circumference and the percentage of abdominal obesity in men has been relatively stable since 2003-2004. (more…)
MedicalResearch.com Interview with:Dr. Sonja Yokum Ph.D.
Oregon Research Institute
Eugene Oregon, 97403
Medical Research: What are the main findings of the study?Dr. Yokum: We found that adolescents showing elevated responses in reward regions to food commercials gained more weight over 1-year follow-up compared to those with less activation in these brain regions. This suggests that there are individual differences in neural vulnerability to food commercials that appear to identify youth at risk for excess weight gain.
MedicalResearch.com Interview with: Bradley Johnston, PhD
Scientist | Child Health Evaluative Sciences
Hospital for Sick Children Research Institute
Assistant Professor | Department of Clinical Epidemiology & Biostatistics
McMaster University Toronto, Ontario, Canada
Medical Research: What are the main findings of the study?Dr. Johnston:
Our findings represent the first meta-analysis using advanced epidemiological methods to summarize popular branded diets for weight loss, trials having been investigated using randomized trial methodology.
Among the 48 original RCTs included in our NMA, low to moderate quality evidence showed that both low-carbohydrate and low-fat diets were associated with an approximate 8 kg weight loss at 6 months when compared to no diet. Approximately 1-2 kg of this effect was lost by 12-months.
Although statistical differences existed among several of the diet macronutrient classes, the differences were small and unlikely to be important to those seeking to lose weight.
Similarly, our results showed that although there are statistically significant differences between some of the brand named diets, these differences are small and not likely patient important.
In terms of potential effect modifiers, behavioural support was significant at 6-months (enhancing weight-loss by 3.23 kg) and exercise was significant at 12-months (enhancing weight loss by 2.13 kg)
Regarding our sensitivity analyses, Differences in weight loss were not clinically important based on risk of bias, missing data, baseline weight, gender, and those with and without specific health conditions
Overall, our findings suggest that patients may choose, among those associated with the largest weight loss, the diet that gives them the least challenges with adherence.
MedicalResearch.com Interview with:Tian Hu, MD, MS Research Fellow
Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine
New Orleans, LA 70112
Medical Research: What are the main findings of the study?Dr. Hu: Participants on the low-carbohydrate diet lost more weight than those on the low-fat diet at 3, 6, and 12 months. At 12 months, those in the low-carbohydrate group lost an average of almost 8 pounds more than those in the low-fat group.
Participants on the low-carbohydrate diet lost more fat mass and did not lose lean mass (muscle) compared to those on the low-fat diet.
Overall, bad cholesterol (low-density lipoprotein cholesterol) that is a predictor of risk for cardiovascular disease decreased on both diets, but good cholesterol (high-density lipoprotein cholesterol) increased more in the low-carbohydrate group.
Physical activity was similar in the groups throughout the study, suggesting that the greater weight loss among participants in the low-carbohydrate group was not because they exercised more.
When we evaluated the black and white participants separately, the results were similar.
MedicalResearch.com Interview with:
Cintia Cercato, MD, PhD and
Emerson Leonildo Marques
University of São Paulo in Brazil
Medical Research: What are the main findings of the study?Answer:The major findings are that the cerebral metabolism of the obese compared to normal weight people is increasing. The fact that it can be increased means a greater chance of Alzheimer's disease, but bariatric surgery can reduce cerebral metabolism of obese.
MedicalResearch.com Interview with:Dr Ellen Flint, BA MSc PhD, Research Fellow
Department of Social & Environmental Health Research
London School of Hygiene & Tropical Medicine
Tavistock Place, London
Medical Research: What are the main findings of the study?Dr. Flint: Men and women who commuted to work by cycling, walking or public transport had significantly lower BMI and percentage body fat than their car-using counterparts. This was the case despite adjustment for a range of factors which may affect both body weight and commuting mode preference (e.g. limiting illness, age, socioeconomic position, sports participation and diet). The differences were of a clinically meaningful magnitude. For example, compared to car users, men who commuted via active or public transportation modes were on average 1 BMI point lighter. For the average man in the sample this would equate to a difference in weight of almost half a stone (3kg).
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