MedicalResearch.com Interview with:
Rania Mekary, MS, Ph.D.
Harvard School of Public Health
Nutrition Department
Boston, Ma 02115
Medical Research: What is the background for this study? What are the main findings?
Dr. Mekar: Findings on weight training and waist circumference (WC) change have been controversial. Moreover, a lot of people focus on aerobic and only aerobic workout... They are not to be blamed because aerobic workout (e.g. jogging) relies mostly on fat as a source of energy while anaerobic workout (e.g. resistance) relies mostly on carbohydrates. Our study, however, showed that resistance training over the long-term was the most inversely associated with waistline change (aka abdominal fat), even more than aerobic exercise. We also justified physiologically why it is the case... It has to do with the greater Excess Post-exercise Oxygen Consumption (EPOC) as compared with aerobic training and also to the muscle adaptation and its increase in mitochondria which leads to more lipid oxidation upon engaging in anaerobic workout over the long-term.
MedicalResearch.com Interview with:
Elina Helander, PhD
Personal Health Informatics
Department of Signal Processing
Tampere University of Technology, Tampere, Finland
Medical Research: What is the background for this study? What are the main findings?
Dr. Helander: Frequent or at least regular self-weighing is a part of behavioral therapy in many weight programs. However, self-weighing frequency typically varies over time. We analyzed almost 3,000 weight observations from 40 overweight individuals that participated in a 1-year health promotion program. These individuals were instructed to weigh themselves daily but eventually had varying self-weighing frequencies. We examined how different self-weighing frequencies of the same individual were linked with weight changes.
We found that weight loss generally occurred during daily weighing. When there were longer breaks in self-weighing such as one month or more, there was a risk of weight gain. We also computed a theoretical minimum self-weighing frequency for having no weight gain that was 5.8 days in our study. That corresponds approximately weekly weighing.
MedicalResearch.com Interview with:
Mohammed Elfaramawi , MD PhD MPH MSc
Assistant Professor
Epidemiology Department
College of Public Health
University of Arkansas for Medical Sciences
Little rock, AR 72205
Medical Research: What is the background for this study? What are the main findings?
Dr. Elfaramawi: A substantial increase in prevalence of obesity has been documented globally. In the USA, overweight and obesity are the second leading cause of preventable death in the USA, affecting ∼97 million adults. Evidence has accumulated showing that visit-to-visit blood pressure variability is associated with adverse cardiovascular outcomes. This study is one of few studies which explored the relationship between obesity and visit-to-visit blood pressure variability.
MedicalResearch.com Interview with:
Dr. Richard Phipps PhD
Department of Environmental Medicine and Flaum Eye Institute,
School of Medicine and Dentistry, University of Rochester, Rochester, New York
Medical Research: What is the background for this study? What are the main findings?
Response: Obesity has risen dramatically over the past 30 years in the United States and throughout the world. Obesity increases morbidity and mortality by increasing health problems such as Type 2 diabetes, cardiovascular disease and cancer. Thus, obesity is one of our greatest challenges worldwide. Our laboratory has been studying a protein called Thy-1 for several decades. Until now its’ true function was unknown. The main finding from our research is that when cells express this protein on their surface, they are inhibited from becoming fat cells. We show in a mouse model system that mice, which lack Thy-1, and given a high fat diet, increase weight much faster than mice that express Thy-1. These mice that lack Thy-1, also have increased levels of many proinflammatory mediators in their blood. In human cells, those that express high levels of Thy-1 are blocked in their ability to become fat cells, unlike the human cells from different tissues that do not express Thy-1. Thus, the main finding is that learning how to manipulate Thy-1 expression could lead to reduced fat cells and reduced fat production. Not only is this an important finding for obesity, but there are many human diseases that are caused by excess fat production in organs, such as, the orbit of the eye, the liver, and the bone marrow.
MedicalResearch.com Interview with:
Susanne Mandrup
Professor, Department of Biochemistry and Molecular Biology
Odense M · Denmark
Medical Research: What is the background for this study? What are the main findings?
Prof. Mandrup: Obesity affects more than 1 billion adults globally and represents one of the greatest current threats to human health. Paradoxially, the fat tissues in the human body that stores excess calories might hold the key for a future obesity treatment.
Most human fat depots are white fat tissues that store energy as fat; however, humans also have small amounts of brown fat, which primarily acts as an effective fat burner for the production of heat. Recent studies have shown that it is possible to “brown” white fat tissues (e.g. by prolonged cold-exposure) leading to an increase in the energy consumption of the body. The challenge is to understand how energy storing white fat cells are reprogrammed into so-called "brite" (brown-in-white) fat cells in the white adipose tissue and thus make adipose tissue burn off excess energy as heat instead of storing it.
In this study we have for the first time investigated how the genome of white fat cells is reprogrammed during browning. We stimulated browning in human white adipocytes by a drug used to treat type II diabetes and compared white and "brite" fat cells. This showed that "brite" fat cells have distinct gene programs which, when active, make these cells particularly energy-consuming. Furthermore, we identified an important factor in the browning process - the gene regulatory protein KLF11 (Kruppel Like Factor-11).
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: Cardiovascular disease is the leading cause of premature mortality in the developed world, and hypertension is its most important risk factor. Controlling hypertension is a major focus of public health initiatives, and dietary approaches have historically focused on sodium.
A reduction in the intake of added sugars, particularly fructose, and specifically in the quantities and context of industrially-manufactured consumables, would help not only curb hypertension rates, but would also help address broader problems related to cardiometabolic disease.
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
consultant neonatologist
Stockholm, Sweden
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.
MedicalResearch.com Interview with:
Michele D. Levine Ph.D.
Associate Professor of Psychiatry and Psychology
Western 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:
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 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.
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:
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:
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.