Change in Brain Volume and Cortical Thickness after Behavioral and Surgical Weight Loss Intervention

Obesity is associated with reduced cortical thickness and brain volume, which may be related to poor nutrition. Given that brain atrophy in anorexia nervosa recovers with nutritional improvements and weight gain, it is worth examining how brain structure changes at the other end of the weight spectrum with weight loss. Thus, this study aimed to examine change in cortical thickness and brain volume in 47 patients with severe obesity who participated in no treatment, behavioral weight loss, or bariatric surgery. T1-weighted MRI scans were conducted pre-treatment and approximately four months later. Measures of cortical thickness, gray matter volume, and white matter volume were compared between time points. Despite overall reduction in BMI, there was no significant change in cortical thickness. There was a significant increase in left hemisphere gray matter and white matter volumes across the sample. At baseline and follow-up, there was no relationship between cortical thickness or brain volumes and BMI. This study is the first to examine changes in cortical thickness and brain volume with weight loss in adults with obesity and the findings show partial support for the hypotheses that weight loss results in increased cortical gray and white matter

Prevalence of COVID-19 in adolescents and youth compared with older adults in states experiencing surges

Purpose There has been considerable controversy regarding susceptibility of adolescents (10–19 years) and youth (15–24 years) to COVID-19. However, a number of studies have reported that adolescents are significantly less susceptible than older adults. Summer 2020 provided an opportunity to examine data on prevalence since after months of lockdowns, with the easing of restrictions, people were mingling, leading to surges in cases. Methods We examined data from Departments of Health websites in six U.S. states experiencing surges in cases to determine prevalence of COVID-19, and two prevalence-related measures, in adolescents and youth as compared to older adults. The two other measures related to prevalence were: (Percentage of cases observed in a given age group) ÷ (percentage of cases expected based on population demographics); and percentage deviation, or [(% observed—% expected)/ % expected] x 100. Results Prevalence of COVID-19 for adolescents and for youth was significantly greater than for older adults (p \u3c .00001), as was percentage observed ÷ percentage expected (p \u3c .005). The percentage deviation was significantly greater in adolescents/youth than in older adults (p \u3c 0.00001) when there was an excess of observed cases over what was expected, and significantly less when observed cases were fewer than expected (p\u3c 0.00001). Conclusions Our results are contrary to previous findings that adolescents are less susceptible than older adults. Possible reasons for the findings are suggested, and we note that public health messaging targeting adolescents and youth might be helpful in curbing the pandemic. Also, the findings of the potential for high transmission among adolescents and youth, should be factored into decisions regarding school reopening

How Does the Brain Implement Adaptive Decision Making to Eat?

Adaptive decision making to eat is crucial for survival, but in anorexia nervosa, the brain persistently supports reduced food intake despite a growing need for energy. How the brain persists in reducing food intake, sometimes even to the point of death and despite the evolution of multiple mechanisms to ensure survival by governing adaptive eating behaviors, remains mysterious. Neural substrates belong to the reward-habit system, which could differ among the eating disorders. The present review provides an overview of neural circuitry of restrictive food choice, binge eating, and the contribution of specific serotonin receptors. One possibility is that restrictive food intake critically engages goal-directed (decision making) systems and “habit,” supporting the view that persistent caloric restriction mimics some aspects of addiction to drugs of abuse

Predicting Changes in Negative Emotional Eating following Bariatric Weight-Loss Surgery

Background: Obesity has been associated with higher rates of social anxiety, and social anxiety has been linked to increased emotional eating. We hypothesized that reductions in BMI and social anxiety following bariatric surgery would predict decreases in negative emotional eating. Methods: Participants were 206 bariatric weight loss surgery patients who completed self-report questionnaires. Liebowitz Social Anxiety Scale (LSAS) scores measured social anxiety. Scores from the negative emotion subscale in the Emotional Appetite Questionnaire (EMAQ) reflected eating due to negative emotions. BMI was calculated from self-report data. All data were collected shortly preceding surgery and at 1-year post surgery. Results: Multiple regression was performed to examine whether changes in BMI and social anxiety predicted changes in negative emotional eating. BMI, social anxiety scores and negative emotional eating decreased significantly 1-year post surgery. Changes in BMI did not significantly predict changes in negative emotional eating. Decreases in social anxiety, however, did predict decreases in negative emotional eating following bariatric surgery, even when controlling for changes in BMI, p = .001. Conclusions: These research findings suggest that there may be behavioral benefits to bariatric surgery when psychosocial improvements occur, independent of weight loss. It would be worthwhile to test whether targeting social anxiety helps reduce negative emotional eating in obese participants

Physiological and Psychological Changes Following Liposuction of Large Volumes of Fat in Overweight and Obese Women

Background: Liposuction can remove a substantial amount of body fat. We investigated the effects of liposuction of large volumes of fat on anthropometrics, body composition (BIA), metabolic hormones, and psychological measures in overweight/obese women. To our knowledge, this is the first study to examine both physiological and psychological changes following liposuction of large volumes of fat in humans. Method: Nine premenopausal healthy overweight/obese women (age = 35.9 ± 7.1 SD, weight = 84.4 kg ± 13.6, BMI = 29.9 kg/m2 ± 2.9) underwent liposuction, removing 3.92 kg ± 1.04 SD of fat. Following an overnight fast, height, weight, waist, and hip circumferences were measured at baseline (one week pre-surgery) and post-surgery (wk 1,4,12). Blood samples were drawn for fasting concentrations of glucose, insulin, leptin, and ghrelin. The Body Shape Questionnaire (BSQ), Body Dysmorphic Disorder (BDD) Examination Self-Report (BDDE-SR), and Zung Self-Rating Depression Scale (ZDS) were administered. Results: Body weight, BMI, waist circumference, and body fat consistently decreased over time (p \u3c .05). Glucose did not change significantly, but insulin decreased from wk 1 to wk 12 (p \u3c .05). Leptin decreased from baseline to wk 1 (p = .01); ghrelin increased but not significantly. Changes in body fat and waist circumference (baseline to wk 1) correlated positively with changes in insulin during that period, and correlated inversely with changes in ghrelin (p \u3c .05). BSQ scores decreased significantly over time (p = .004), but scores for BDDE-SR (p = .10) and ZDS (p = .24) did not change significantly. Conclusion: Liposuction led to significant decreases in body weight and fat, waist circumference, and leptin levels. Changes in body fat and waist circumference correlated with concurrent changes in the adipose-related hormones, insulin and ghrelin (baseline to wk 1), and body shape perception improved. Thus, besides the obvious cosmetic effects, liposuction led to several positive body composition, hormonal, and psychological changes

Obesity-Related Hormones and Metabolic Risk Factors: A Randomized Trial of Diet Plus Either Strength or Aerobic Training versus Diet Alone in Overweight Participants

There is debate about the additive effects of exercise in conjunction with diet to treat obesity, and not much is known about the differential effects of strength versus aerobic training. This randomized controlled trial examined the effects of diet plus strength training, diet plus aerobic training, or diet only on metabolic risk factors associated with obesity. Eighty-one overweight and obese participants completed the 8-week intervention. All participants received an energy-restrictive formula diet with an energy content based on 70% of measured resting metabolic rate (RMR). Participants assigned to an exercise group trained 3 days/week under supervision. Anthropometrics and fasting hormones were assessed pre- and post-intervention. Mean weight loss (8.5 ± 4.3kg SD) did not differ between groups nor did reductions in BMI or body fat, although the diet plus strength training group showed marginally greater lean mass retention. There were significant improvements in the values and number of metabolic syndrome risk factors, and decreases in insulin concentrations and insulin resistance, which did not vary between groups. For men, testosterone increased significantly more in the diet plus aerobic training as compared to the other groups. As compared to diet alone, the addition of strength or aerobic training did not improve changes in BMI, body fat, or metabolic risk factors although the diet plus strength training group showed a trend toward preservation of lean mass, and the diet plus aerobic group in men resulted in increased testosterone

Skipping Breakfast Leads to Weight Loss but Also Elevated Cholesterol Compared with Consuming Daily Breakfasts of Oat Porridge or Frosted Cornflakes in Overweight Individuals: A Randomised Controlled Trial

Eating breakfast may reduce appetite, body weight and CVD risk factors, but the breakfast type that produces the greatest health benefits remains unclear. We compared the effects of consuming a high-fibre breakfast, a non-fibre breakfast, or no-breakfast control on body weight, CVD risk factors and appetite. A total of thirty-six overweight participants (eighteen men and eighteen women) (mean age 33·9 (SD 7·5) years, mean BMI 32·8 (SD 4·7) kg/m2) were randomly assigned to consume oat porridge (n = 12), frosted cornflakes (n = 12) or a water control (n = 12) breakfast daily for 4 weeks. Appetite ratings were collected on the first day and weekly thereafter. Before and after the intervention, body weight, composition, blood pressure and resting energy expenditure (REE) were measured and a fasting blood sample was collected. Across the 4 weeks, fullness was higher and hunger was lower in the oat porridge group compared with the control group (P \u3c 0·05). Mean weight change over the intervention was significantly different in the control group (−1·18 (SD 1·16) kg) compared with both the cornflakes (−0·12 (SD 1·34) kg) and oat porridge (+0·26 (SD 0·91) kg) groups (P \u3c 0·05). However, the control group also showed elevated total cholesterol concentrations relative to the cornflakes and oat porridge groups (P \u3c 0·05). There were no differences between groups in changes in body composition, blood pressure, REE or other CVD risk factors. In conclusion, although skipping breakfast led to weight loss, it also resulted in increased total cholesterol concentrations compared with eating either oat porridge or frosted cornflakes for breakfast

Ghrelin

Background: The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope of review: In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. Major conclusions: In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism

Association of Body Mass and Brain Activation during Gastric Distention: Implications for Obesity

BACKGROUND:Gastric distention (GD), as it occurs during meal ingestion, signals a full stomach and it is one of the key mechanisms controlling food intake. Previous studies on GD showed lower activation of the amygdala for subjects with higher body mass index (BMI). Since obese subjects have dopaminergic deficits that correlate negatively with BMI and the amygdala is innervated by dopamine neurons, we hypothesized that BMI would correlate negatively with activation not just in the amygdala but also in other dopaminergic brain regions (midbrain and hypothalamus). METHODOLOGY/PRINCIPAL FINDINGS:We used functional magnetic resonance imaging (fMRI) to evaluate brain activation during GD in 24 healthy subjects with BMI range of 20-39 kg/m(2). Using multiple regression and cross-correlation analyses based on a family-wise error corrected threshold P = 0.05, we show that during slow GD to maximum volumes of 500 ml and 700 ml subjects with increased BMI had increased activation in cerebellum and left posterior insula, and decreased activation of dopaminergic (amygdala, midbrain, hypothalamus, thalamus) and serotonergic (pons) brain regions and anterior insula, regions that were functionally interconnected with one another. CONCLUSIONS:The negative correlation between BMI and BOLD responses to gastric distention in dopaminergic (midbrain, hypothalamus, amygdala, thalamus) and serotonergic (pons) brain regions is consistent with disruption of dopaminergic and serotonergic signaling in obesity. In contrast the positive correlation between BMI and BOLD responses in posterior insula and cerebellum suggests an opposing mechanism that promotes food intake in obese subjects that may underlie their ability to consume at once large food volumes despite increasing gastric distention