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Showing papers in "Obesity in 2011"


Journal ArticleDOI
01 May 2011-Obesity
TL;DR: A new parameter, the body adiposity index (BAI), which can be calculated from hip circumference and height only, can be used in the clinical setting even in remote locations with very limited access to reliable scales and estimates %adiposity directly.
Abstract: Obesity is a growing problem in the United States and throughout the world. It is a risk factor for many chronic diseases. The BMI has been used to assess body fat for almost 200 years. BMI is known to be of limited accuracy, and is different for males and females with similar %body adiposity. Here, we define an alternative parameter, the body adiposity index (BAI = ((hip circumference)/((height)1.5) − 18)). The BAI can be used to reflect %body fat for adult men and women of differing ethnicities without numerical correction. We used a population study, the “BetaGene” study, to develop the new index of body adiposity. %Body fat, as measured by the dual-energy X-ray absorptiometry (DXA), was used as a “gold standard” for validation. Hip circumference (R = 0.602) and height (R = −0.524) are strongly correlated with %body fat and therefore chosen as principal anthropometric measures on which we base BAI. The BAI measure was validated in the “Triglyceride and Cardiovascular Risk in African-Americans (TARA)” study of African Americans. Correlation between DXA-derived %adiposity and the BAI was R = 0.85 for TARA with a concordance of C_b = 0.95. BAI can be measured without weighing, which may render it useful in settings where measuring accurate body weight is problematic. In summary, we have defined a new parameter, the BAI, which can be calculated from hip circumference and height only. It can be used in the clinical setting even in remote locations with very limited access to reliable scales. The BAI estimates %adiposity directly.

779 citations


Journal ArticleDOI
01 Jun 2011-Obesity
TL;DR: The CAF provided a robust model of human metabolic syndrome compared to traditional lard‐based HFD, creating a phenotype of exaggerated obesity with glucose intolerance and inflammation, and displayed remarkable inflammation in white fat, brown fat and liver compared to HFD and controls.
Abstract: Obesity has reached epidemic proportions worldwide and reports estimate that American children consume up to 25% of calories from snacks. Several animal models of obesity exist, but studies are lacking that compare high-fat diets (HFD) traditionally used in rodent models of diet-induced obesity (DIO) to diets consisting of food regularly consumed by humans, including high-salt, high-fat, low-fiber, energy dense foods such as cookies, chips, and processed meats. To investigate the obesogenic and inflammatory consequences of a cafeteria diet (CAF) compared to a lard-based 45% HFD in rodent models, male Wistar rats were fed HFD, CAF or chow control diets for 15 weeks. Body weight increased dramatically and remained significantly elevated in CAF-fed rats compared to all other diets. Glucose- and insulin-tolerance tests revealed that hyperinsulinemia, hyperglycemia, and glucose intolerance were exaggerated in the CAF-fed rats compared to controls and HFD-fed rats. It is well-established that macrophages infiltrate metabolic tissues at the onset of weight gain and directly contribute to inflammation, insulin resistance, and obesity. Although both high fat diets resulted in increased adiposity and hepatosteatosis, CAF-fed rats displayed remarkable inflammation in white fat, brown fat and liver compared to HFD and controls. In sum, the CAF provided a robust model of human metabolic syndrome compared to traditional lard-based HFD, creating a phenotype of exaggerated obesity with glucose intolerance and inflammation. This model provides a unique platform to study the biochemical, genomic and physiological mechanisms of obesity and obesity-related disease states that are pandemic in western civilization today.

503 citations


Journal ArticleDOI
01 Feb 2011-Obesity
TL;DR: Sex differences, and in some instances race differences, in the relationships between anthropometry and fat‐specific depots demonstrate that these characteristics need to be considered when predicting adiposity from WC or BMI.
Abstract: The purpose of this study was to examine sex and race differences in the relationship between anthropometric measurements and adiposity in white and African-American (AA) adults Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas were measured with computed tomography (CT) Fat mass (FM) was measured with dual-energy-X-ray absorptiometry (DXA) Correlation coefficients were used to assess the relationship of waist circumference (WC) and BMI to VAT, SAT, and FM within sex-by-race groups General linear models were used to compare relationships between WC or BMI, and adiposity across sex and race, within age groups (18–39 and 40–64 years) The sample included 1,667 adults (men: 489 white; 120 AA; women: 666 white, 392 AA) WC and BMI correlations were highest for FM and SAT compared to VAT Women had higher FM levels than men regardless of WC, but the sex difference in FM was attenuated in younger AA adults with a high BMI For a given level of WC or BMI, women had higher levels of SAT than men; however, significant interactions indicated that the relationship was not consistent across all levels of BMI and WC Sex and race differences in VAT varied significantly with WC and BMI In general, white adults had higher levels of VAT than AA adults at higher levels of BMI and WC Sex differences, and in some instances race differences, in the relationships between anthropometry and fat-specific depots demonstrate that these characteristics need to be considered when predicting adiposity from WC or BMI

461 citations


Journal ArticleDOI
01 Jul 2011-Obesity
TL;DR: It is indicated that caloric intake after 8:00 pm may increase the risk of obesity, independent of sleep timing and duration, and future studies should investigate the biological and social mechanisms linking timing of sleep and feeding in order to develop novel time‐based interventions for weight management.
Abstract: Sleep duration has been linked to obesity and there is also an emerging literature in animals demonstrating a relationship between the timing of feeding and weight regulation. However, there is a paucity of research evaluating timing of sleep and feeding on weight regulation in humans. The goal of this study was to evaluate the role of sleep timing in dietary patterns and BMI. Participants included 52 (25 females) volunteers who completed 7 days of wrist actigraphy and food logs. Fifty-six percent were "normal sleepers" (midpoint of <5:30 AM) and 44% were "late sleepers" (midpoint of sleep ≥5:30 AM). Late sleepers had shorter sleep duration, later sleep onset and sleep offset and meal times. Late sleepers consumed more calories at dinner and after 8:00 PM, had higher fast food, full-calorie soda and lower fruit and vegetable consumption. Higher BMI was associated with shorter sleep duration, later sleep timing, caloric consumption after 8:00 PM, and fast food meals. In multivariate models, sleep timing was independently associated with calories consumed after 8:00 PM and fruit and vegetable consumption but did not predict BMI after controlling for sleep duration. Calories consumed after 8:00 PM predicted BMI after controlling for sleep timing and duration. These findings indicate that caloric intake after 8:00 PM may increase the risk of obesity, independent of sleep timing and duration. Future studies should investigate the biological and social mechanisms linking timing of sleep and feeding in order to develop novel time-based interventions for weight management.

459 citations


Journal ArticleDOI
01 Jan 2011-Obesity
TL;DR: The present findings support the efficacy of combined naltrexone/bupropion therapy as an adjunct to intensive BMOD for obesity, and the former had significantly greater improvements in markers of cardiometabolic disease risk.
Abstract: This 56-week, randomized, placebo-controlled trial examined the efficacy and safety of naltrexone plus bupropion as an adjunct to intensive behavior modification (BMOD). A total of 793 participants (BMI = 36.5 ± 4.2 kg/m2) was randomly assigned in a 1:3 ratio to: (i) placebo + BMOD (N = 202); or (ii) naltrexone sustained-release (SR, 32 mg/day), combined with bupropion SR (360 mg/day) plus BMOD (i.e., NB32 + BMOD; N = 591). Both groups were prescribed an energy-reduced diet and 28 group BMOD sessions. Co-primary end points were percentage change in weight and the proportion of participants who lost ≥5% weight at week 56. Efficacy analyses were performed on a modified intent-to-treat population (ITT; i.e., participants with ≥1 postbaseline weight while taking study drug (placebo + BMOD, N = 193; NB32 + BMOD, N = 482)). Missing data were replaced with the last observation obtained on study drug. At week 56, weight loss was 5.1 ± 0.6% with placebo + BMOD vs. 9.3 ± 0.4% with NB32 + BMOD (P < 0.001). A completers analysis revealed weight losses of 7.3 ± 0.9% (N = 106) vs. 11.5 ± 0.6% (N = 301), respectively (P < 0.001). A third analysis, which included all randomized participants, yielded losses of 4.9 ± 0.6 vs. 7.8 ± 0.4%, respectively (P < 0.001). Significantly more NB32 + BMOD- vs. placebo + BMOD-treated participants lost ≥5 and ≥10% of initial weight, and the former had significantly greater improvements in markers of cardiometabolic disease risk. NB32 + BMOD was generally well tolerated, although associated with more reports of nausea than placebo + BMOD. The present findings support the efficacy of combined naltrexone/bupropion therapy as an adjunct to intensive BMOD for obesity.

424 citations


Journal ArticleDOI
01 Jul 2011-Obesity
TL;DR: Assessing BF% may help to diagnose disturbed glucose tolerance beyond information provided by BMI and waist circumference in particular in male subjects with BMI <25 kg/m2 and over the age of 40, and in the overweight or obese‐classified individuals.
Abstract: Obesity is the major risk factor for the development of prediabetes and type 2 diabetes. BMI is widely used as a surrogate measure of obesity, but underestimates the prevalence of obesity, defined as an excess of body fat. We assessed the presence of impaired glucose tolerance or impaired fasting glucose (both considered together as prediabetes) or type 2 diabetes in relation to the criteria used for the diagnosis of obesity using BMI as compared to body fat percentage (BF%). We performed a cross-sectional study including 4,828 (587 lean, 1,320 overweight, and 2,921 obese classified according to BMI) white subjects (66% females), aged 18-80 years. BMI, BF% determined by air-displacement plethysmography (ADP) and conventional blood markers of glucose metabolism and lipid profile were measured. We found a higher than expected number of subjects with prediabetes or type 2 diabetes in the obese category according to BF% when the sample was globally analyzed (P < 0.0001) and in the lean BMI-classified subjects (P < 0.0001), but not in the overweight or obese-classified individuals. Importantly, BF% was significantly higher in lean (by BMI) women with prediabetes or type 2 diabetes as compared to those with normoglycemia (NG) (35.5 ± 7.0 vs. 30.3 ± 7.7%, P < 0.0001), whereas no differences were observed for BMI. Similarly, increased BF% was found in lean BMI-classified men with prediabetes or type 2 diabetes (25.2 ± 9.0 vs. 19.9 ± 8.0%, P = 0.008), exhibiting no differences in BMI or waist circumference. In conclusion, assessing BF% may help to diagnose disturbed glucose tolerance beyond information provided by BMI and waist circumference in particular in male subjects with BMI <25 kg/m(2) and over the age of 40.

404 citations


Journal ArticleDOI
01 Sep 2011-Obesity
TL;DR: The results suggest that decreased BAT activity may be associated with accumulation of body fat with age, and the adiposity‐related parameters showed some sex differences, but increased with age in the BAT‐negative group, in both sexes.
Abstract: Brown adipose tissue (BAT) can be identified by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) combined with X-ray computed tomography (CT) in adult humans. The objective of this study was to clarify the relationship between BAT and adiposity in healthy adult humans, particularly to test the idea that decreased BAT activity may be associated with body fat accumulation with age. One hundred and sixty-two healthy volunteers aged 20–73 years (103 males and 59 females) underwent FDG-PET/CT after 2-h cold exposure at 19 °C with light clothing. Cold-activated BAT was detected in 41% of the subjects (BAT-positive). Compared with the BAT-negative group, the BAT-positive group was younger (P < 0.01) and showed a lower BMI (P < 0.01), body fat content (P < 0.01), and abdominal fat (P < 0.01). The incidence of cold-activated BAT decreased with age (P < 0.01), being more than 50% in the twenties, but less than 10% in the fifties and sixties. The adiposity-related parameters showed some sex differences, but increased with age in the BAT-negative group (P < 0.01), while they remained unchanged from the twenties to forties in the BAT-positive group, in both sexes. These results suggest that decreased BAT activity may be associated with accumulation of body fat with age.

398 citations


Journal ArticleDOI
01 Oct 2011-Obesity
TL;DR: Results provide critical evidence that a comprehensive lifestyle intervention can induce clinically significant weight loss (i.e., ≥5%) in overweight/obese participants with type 2 diabetes and maintain this loss in more than 45% of patients at 4 years.
Abstract: This report provides a further analysis of the year 4 weight losses in the Look AHEAD (Action for Health in Diabetes) study and identifies factors associated with long-term success. A total of 5,145 overweight/obese men and women with type 2 diabetes were randomly assigned to an intensive lifestyle intervention (ILI) or a usual care group, referred to as Diabetes Support and Education (DSE). ILI participants were provided approximately weekly group or individual treatment in year 1; continued but less frequent contact was provided in years 2-4. DSE participants received three group educational sessions in all years. As reported previously, at year 4, ILI participants lost an average of 4.7% of initial weight, compared with 1.1% for DSE (P < 0.0001). More ILI than DSE participants lost ≥ 5% (46% vs. 25%, P < 0.0001) and ≥ 10% (23% vs. 10%, P < 0.0001) of initial weight. Within the ILI, achievement of both the 5% and 10% categorical weight losses at year 4 was strongly related to meeting these goals at year 1. A total of 887 participants in ILI lost ≥ 10% at year 1, of whom 374 (42.2%) achieved this loss at year 4. Participants who maintained the loss, compared with those who did not, attended more treatment sessions and reported more favorable physical activity and food intake at year 4. These results provide critical evidence that a comprehensive lifestyle intervention can induce clinically significant weight loss (i.e., ≥ 5%) in overweight/obese participants with type 2 diabetes and maintain this loss in more than 45% of patients at 4 years.

393 citations


Journal ArticleDOI
01 Jan 2011-Obesity
TL;DR: The results suggest that BAT is involved in cold‐induced increases in whole‐body energy expenditure, and, thereby, the control of body temperature and adiposity in adult humans.
Abstract: Brown adipose tissue (BAT) can be identified by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in adult humans. Thirteen healthy male volunteers aged 20–28 years underwent FDG-PET after 2-h cold exposure at 19 °C with light-clothing and intermittently putting their legs on an ice block. When exposed to cold, 6 out of the 13 subjects showed marked FDG uptake into adipose tissue of the supraclavicular and paraspinal regions (BAT-positive group), whereas the remaining seven showed no detectable uptake (BAT-negative group). The BMI and body fat content were similar in the two groups. Under warm conditions at 27 °C, the energy expenditure of the BAT-positive group estimated by indirect calorimetry was 1,446 ± 97 kcal/day, being comparable with that of the BAT-negative group (1,434 ± 246 kcal/day). After cold exposure, the energy expenditure increased markedly by 410 ± 293 (P < 0.05) and slightly by 42 ± 114 kcal/day (P = 0.37) in the BAT-positive and -negative groups, respectively. A positive correlation (P < 0.05) was found between the cold-induced rise in energy expenditure and the BAT activity quantified from FDG uptake. After cold exposure, the skin temperature in the supraclavicular region close to BAT deposits dropped by 0.14 °C in the BAT-positive group, whereas it dropped more markedly (P < 0.01) by 0.60 °C in the BAT-negative group. The skin temperature drop in other regions apart from BAT deposits was similar in the two groups. These results suggest that BAT is involved in cold-induced increases in whole-body energy expenditure, and, thereby, the control of body temperature and adiposity in adult humans.

373 citations


Journal ArticleDOI
01 Sep 2011-Obesity
TL;DR: Results indicate that overweight is related to greater attentional bias to food cues and that youth who show elevated reward circuitry responsivity during food cue exposure are at increased risk for weight gain.
Abstract: Behavioral studies reveal that obese vs. lean individuals show attentional bias to food stimuli. Yet research has not investigated this relation using objective brain imaging or tested whether attentional bias to food stimuli predicts future weight gain, which are important aims given the prominence of food cues in the environment. We used functional magnetic resonance imaging (fMRI) to examine attentional bias in 35 adolescent girls ranging from lean to obese using an attention network task involving food and neutral stimuli. BMI correlated positively with speed of behavioral response to both appetizing food stimuli and unappetizing food stimuli, but not to neutral stimuli. BMI correlated positively with activation in brain regions related to attention and food reward, including the anterior insula/frontal operculum, lateral orbitofrontal cortex (OFC), ventrolateral prefrontal cortex (vlPFC), and superior parietal lobe, during initial orientation to food cues. BMI also correlated with greater activation in the anterior insula/frontal operculum during reallocation of attention to appetizing food images and with weaker activation in the medial OFC and ventral pallidum during reallocation of attention to unappetizing food images. Greater lateral OFC activation during initial orientation to appetizing food cues predicted future increases in BMI. Results indicate that overweight is related to greater attentional bias to food cues and that youth who show elevated reward circuitry responsivity during food cue exposure are at increased risk for weight gain.

367 citations


Journal ArticleDOI
01 Jul 2011-Obesity
TL;DR: This is the first report of these associations in adolescents between obesity, executive function, disinhibition, and brain volumes in relatively healthy youth and point to the importance of better understanding the associations between neurostructural deficits and obesity.
Abstract: In adults, obesity has been associated with disinhibited eating, decreased cortical gray matter (GM) volume, and lower performance on cognitive assessments. Much less is known about these relationships in adolescence and there are no studies assessing behavioral, cognitive, and neurostructural measures in the same group of study participants. This study examined the relationship between obesity, executive function, disinhibition, and brain volumes in relatively healthy youth. Participants included 54 obese and 37 lean adolescents. Participants received a cognitive battery, questionnaires of eating behaviors, and magnetic resonance imaging (MRI). Neuropsychological assessments included tasks targeting frontal lobe function. Eating behaviors were determined using the Three Factor Eating Questionnaire (TFEQ), and structural MRIs were performed on a 1.5 T Siemens Avanto MRI System (Siemens, Erlangen, Germany) to determine brain GM volumes. Lean and obese adolescents were matched on age, years of education, gender, and socioeconomic status. Relative to lean adolescents, obese participants had significantly higher ratings of disinhibition on the TFEQ, lower performance on the cognitive tests, and lower orbitofrontal cortex (OFC) volume. Disinhibition significantly correlated with BMI, Stroop color-word score, and OFC volume. This is the first report of these associations in adolescents and point to the importance of better understanding the associations between neurostructural deficits and obesity.

Journal ArticleDOI
01 Apr 2011-Obesity
TL;DR: In this paper, the authors examined whether internalized societal attitudes about weight moderated the impact of weight stigma and found that weight stigma was positively correlated with body dissatisfaction, drive for thinness, and bulimic symptoms, and negatively correlated with state and trait self-esteem.
Abstract: Experiences with weight stigma negatively impact both psychological outcomes (e.g., body dissatisfaction, depression) and behavioral outcomes (e.g., dieting, exercise). However, not everyone is equally affected by experiences with weight stigma. This study examined whether internalized societal attitudes about weight moderated the impact of weight stigma. Adult participants (n = 111) completed measures of experiences with weight stigma, as well as two indexes of internalized societal attitudes (the moderators): Internalized anti-fat attitudes and internalization of societal standards of attractiveness. Psychological outcomes included self-esteem, body dissatisfaction, drive for thinness, and bulimic symptoms; behavioral outcomes included avoidance of exercise and self-reported exercise behavior. Weight stigma was positively correlated with body dissatisfaction, drive for thinness, and bulimic symptoms, and was negatively correlated with state and trait self-esteem. Both indexes of internalized attitudes moderated the association between weight stigma and avoidance of exercise: Individuals high in anti-fat attitudes and high in internalization of societal standards of attractiveness were more motivated to avoid exercise if they also experienced a high degree of weight stigma; individuals low in anti-fat attitudes and low in internalization were relatively unaffected. Avoidance of exercise was negatively correlated with self-reported strenuous exercise. These findings suggest that weight stigma can negatively influence motivation to exercise, particularly among individuals who have internalized societal attitudes about weight. Reducing internalization might be a means of minimizing the negative impact of weight stigma and of facilitating healthy weight management efforts.

Journal ArticleDOI
01 Feb 2011-Obesity
TL;DR: Using a personal digital assistant with dietary and exercise software, with and without a feedback message, compared to using a paper diary/record, results in greater weight loss and improved self‐monitoring adherence.
Abstract: Technology may improve self-monitoring adherence and dietary changes in weight loss treatment. Our study aimed to investigate whether using a personal digital assistant (PDA) with dietary and exercise software, with and without a feedback message, compared to using a paper diary/record (PR), results in greater weight loss and improved self-monitoring adherence. Healthy adults (N = 210) with a mean BMI of 34.01 kg/m(2) were randomized to one of three self-monitoring approaches: PR (n = 72), PDA with self-monitoring software (n = 68), or PDA with self-monitoring software and daily feedback messages (PDA+FB, n = 70). All participants received standard behavioral treatment. Self-monitoring adherence and change in body weight, waist circumference, and diet were assessed at 6 months; retention was 91%. All participants had a significant weight loss (P < 0.01) but weight loss did not differ among groups. A higher proportion of PDA+FB participants (63%) achieved ≥ 5% weight loss in comparison to the PR group (46%) (P < 0.05) and PDA group (49%) (P = 0.09). Median percent self-monitoring adherence over the 6 months was higher in the PDA groups (PDA 80%; PDA+FB 90%) than in the PR group (55%) (P < 0.01). Waist circumference decreased more in the PDA groups than the PR group (P = 0.02). Similarly, the PDA groups reduced energy and saturated fat intake more than the PR group (P < 0.05). Self-monitoring adherence was greater in the PDA groups with the greatest weight change observed in the PDA+FB group.

Journal ArticleDOI
01 Aug 2011-Obesity
TL;DR: Dopamine neurotransmission in the caudate is identified as being of relevance to the neurobiology of BED, suggesting that dopamine release per se does not predict BMI within a group of obese individuals but that it predicts binge eating.
Abstract: Subjects with binge eating disorder (BED) regularly consume large amounts of food in short time periods. The neurobiology of BED is poorly understood. Brain dopamine, which regulates motivation for food intake, is likely to be involved. We assessed the involvement of brain dopamine in the motivation for food consumption in binge eaters. Positron emission tomography (PET) scans with [11C]raclopride were done in 10 obese BED and 8 obese subjects without BED. Changes in extracellular dopamine in the striatum in response to food stimulation in food-deprived subjects were evaluated after placebo and after oral methylphenidate (MPH), a drug that blocks the dopamine reuptake transporter and thus amplifies dopamine signals. Neither the neutral stimuli (with or without MPH) nor the food stimuli when given with placebo increased extracellular dopamine. The food stimuli when given with MPH significantly increased dopamine in the caudate and putamen in the binge eaters but not in the nonbinge eaters. Dopamine increases in the caudate were significantly correlated with the binge eating scores but not with BMI. These results identify dopamine neurotransmission in the caudate as being of relevance to the neurobiology of BED. The lack of correlation between BMI and dopamine changes suggests that dopamine release per se does not predict BMI within a group of obese individuals but that it predicts binge eating.

Journal ArticleDOI
01 Jan 2011-Obesity
TL;DR: The study showed that vertebral bone marrow fat is positively associated with visceral fat and inversely associated with IGF‐1 and BMD, which suggests that the detrimental effect of visceral fat on bone health may be mediated in part by IGF-1 as an important regulator of the fat and bone lineage.
Abstract: Recent studies have demonstrated an important physiologic link between bone and fat. Bone and fat cells arise from the same mesenchymal precursor cell within bone marrow, capable of differentiation into adipocytes or osteoblasts. Increased BMI appears to protect against osteoporosis. However, recent studies have suggested detrimental effects of visceral fat on bone health. Increased visceral fat may also be associated with decreased growth hormone (GH) and insulin-like growth factor 1 (IGF-1) levels which are important for maintenance of bone homeostasis. The purpose of our study was to assess the relationship between vertebral bone marrow fat and trabecular bone mineral density (BMD), abdominal fat depots, GH and IGF-1 in premenopausal women with obesity. We studied 47 premenopausal women of various BMI (range: 18–41 kg/m2, mean 30 ± 7 kg/m2) who underwent vertebral bone marrow fat measurement with proton magnetic resonance spectroscopy (1H-MRS), body composition, and trabecular BMD measurement with computed tomography (CT), and GH and IGF-1 levels. Women with high visceral fat had higher bone marrow fat than women with low visceral fat. There was a positive correlation between bone marrow fat and visceral fat, independent of BMD. There was an inverse association between vertebral bone marrow fat and trabecular BMD. Vertebral bone marrow fat was also inversely associated with IGF-1, independent of visceral fat. Our study showed that vertebral bone marrow fat is positively associated with visceral fat and inversely associated with IGF-1 and BMD. This suggests that the detrimental effect of visceral fat on bone health may be mediated in part by IGF-1 as an important regulator of the fat and bone lineage.

Journal Article
01 Jun 2011-Obesity
TL;DR: It is concluded that psychosocial stress is a risk factor for weight gain but effects are very small, and variation across studies indicates there are moderating variables to be elucidated.
Abstract: Psychosocial stress has been strongly implicated in the biology of adiposity but epidemiological studies have produced inconsistent results. The aim of this analysis was to bring together results from published, longitudinal, prospective studies examining associations between psychosocial stress and objectively measured adiposity in a meta‐analysis. Searches were conducted on Medline, PsycINFO, Web of Science, and PubMed (to January 2009) and reference lists from relevant articles were examined. Prospective studies relating psychosocial stress (general life stress (including caregiver stress), work stress) to BMI, body fat, body weight, waist circumference, or waist‐to‐hip ratio were included. Analyses from 14 cohorts were collated and evaluated. There was no significant heterogeneity, no evidence of publication bias, and no association between study quality and outcomes. The majority of analyses found no significant relationship between stress and adiposity (69%), but among those with significant effects, more found positive than negative associations (25 vs. 6%). Combining results in a meta‐analysis showed that stress was associated with increasing adiposity (r = 0.014; confidence interval (CI) = 0.002–0.025, P < 0.05). Effects were stronger for men than women, in analyses with longer rather than shorter follow‐ups, and in better quality studies. We conclude that psychosocial stress is a risk factor for weight gain but effects are very small. Variability across studies indicates there are moderating variables to be elucidated.

Journal ArticleDOI
01 Apr 2011-Obesity
TL;DR: In this article, the authors brought together results from published, longitudinal, prospective studies examining associations between psychosocial stress and objectively measured adiposity in a meta-analysis and concluded that stress was associated with increasing adiposity.
Abstract: Psychosocial stress has been strongly implicated in the biology of adiposity but epidemiological studies have produced inconsistent results. The aim of this analysis was to bring together results from published, longitudinal, prospective studies examining associations between psychosocial stress and objectively measured adiposity in a meta-analysis. Searches were conducted on Medline, PsycINFO, Web of Science, and PubMed (to January 2009) and reference lists from relevant articles were examined. Prospective studies relating psychosocial stress (general life stress (including caregiver stress), work stress) to BMI, body fat, body weight, waist circumference, or waist-to-hip ratio were included. Analyses from 14 cohorts were collated and evaluated. There was no significant heterogeneity, no evidence of publication bias, and no association between study quality and outcomes. The majority of analyses found no significant relationship between stress and adiposity (69%), but among those with significant effects, more found positive than negative associations (25 vs. 6%). Combining results in a meta-analysis showed that stress was associated with increasing adiposity (r = 0.014; confidence interval (CI) = 0.002-0.025, P < 0.05). Effects were stronger for men than women, in analyses with longer rather than shorter follow-ups, and in better quality studies. We conclude that psychosocial stress is a risk factor for weight gain but effects are very small. Variability across studies indicates there are moderating variables to be elucidated.

Journal ArticleDOI
01 Nov 2011-Obesity
TL;DR: The interaction between food reward sensitivity and inhibitory control was a significant predictor of palatable food intake in regression analyses controlling for BMI and the amount of preload consumed, but no associations were found in a similar regression analysis predicting intake of bland foods.
Abstract: Overeating is believed to result when the appetitive motivation to consume palatable food exceeds an individual's capacity for inhibitory control of eating This hypothesis was supported in recent studies involving predominantly normal weight women, but has not been tested in obese populations The current study tested the interaction between food reward sensitivity and inhibitory control in predicting palatable food intake among energy-replete overweight and obese women (N = 62) Sensitivity to palatable food reward was measured with the Power of Food Scale Inhibitory control was assessed with a computerized choice task that captures the tendency to discount large delayed rewards relative to smaller immediate rewards Participants completed an eating in the absence of hunger protocol in which homeostatic energy needs were eliminated with a bland preload of plain oatmeal, followed by a bogus laboratory taste test of palatable and bland snacks The interaction between food reward sensitivity and inhibitory control was a significant predictor of palatable food intake in regression analyses controlling for BMI and the amount of preload consumed Probing this interaction indicated that higher food reward sensitivity predicted greater palatable food intake at low levels of inhibitory control, but was not associated with intake at high levels of inhibitory control As expected, no associations were found in a similar regression analysis predicting intake of bland foods Findings support a neurobehavioral model of eating behavior in which sensitivity to palatable food reward drives overeating only when accompanied by insufficient inhibitory control Strengthening inhibitory control could enhance weight management programs

Journal ArticleDOI
01 Oct 2011-Obesity
TL;DR: It is suggested that among overweight women, exposure to weight stigmatizing material may lead to increased caloric consumption, which directly challenges the notion that pressure to lose weight in the form of weight stigma will have a positive, motivating effect on overweight individuals.
Abstract: The present study assessed the influence of exposure to weight stigma on energy intake in both overweight and normal-weight adult women. Seventy-three women (mean age: 31.71 ± 12.72 years), both overweight (n = 34) and normal weight (n = 39), were randomly assigned to view one of two videos depicting either weight stigmatizing material or neutral material, after which they consumed snacks ad libitum. Pre- and post-video measures included blood pressure, attitudes toward overweight individuals, and positive and negative affect. Participants' body weight was measured, as was the number of kilocalories consumed following video exposure. Overweight women who watched the stigmatizing video ate more than three times as many kilocalories as overweight women who watched the neutral video (302.82 vs. 89.00 kcal), and significantly more calories than the normal-weight individuals who watched either the stigmatizing or the neutral video. A two-by-two analysis of covariance revealed that even after adjusting for relevant covariates, there was a significant interaction between video type and weight status in that when overweight, individuals consumed significantly more calories if they were in the stigmatizing condition vs. the neutral condition (F(1,65) = 4.37, P = 0.04, η(2) = 0.03). These findings suggest that among overweight women, exposure to weight stigmatizing material may lead to increased caloric consumption. This directly challenges the notion that pressure to lose weight in the form of weight stigma will have a positive, motivating effect on overweight individuals.

Journal ArticleDOI
01 Apr 2011-Obesity
TL;DR: The sugar profile analyses detected forms of sugar that were inconsistent with what was listed on the food labels and the tendency for use of HFCS that is higher in fructose could be contributing to higher fructose consumption than would otherwise be assumed.
Abstract: The consumption of fructose, largely in the form of high fructose corn syrup (HFCS), has risen over the past several decades and is thought to contribute negatively to metabolic health. However, the fructose content of foods and beverages produced with HFCS is not disclosed and estimates of fructose content are based on the common assumption that the HFCS used contains 55% fructose. The objective of this study was to conduct an objective laboratory analysis of the sugar content and composition in popular sugar-sweetened beverages with a particular focus on fructose content. Twenty-three sugar-sweetened beverages along with four standard solutions were analyzed for sugar profiles using high-performance liquid chromatography (HPLC) in an independent, certified laboratory. Total sugar content was calculated as well as percent fructose in the beverages that use HFCS as the sole source of fructose. Results showed that the total sugar content of the beverages ranged from 85 to 128% of what was listed on the food label. The mean fructose content in the HFCS used was 59% (range 47–65%) and several major brands appear to be produced with HFCS that is 65% fructose. Finally, the sugar profile analyses detected forms of sugar that were inconsistent with what was listed on the food labels. This analysis revealed significant deviations in sugar amount and composition relative to disclosures from producers. In addition, the tendency for use of HFCS that is higher in fructose could be contributing to higher fructose consumption than would otherwise be assumed.

Journal ArticleDOI
01 Feb 2011-Obesity
TL;DR: Testing the independent and combined effects of two behavioral interventions delivered to parents, designed to promote healthy infant growth in the first year, suggests that multicomponent behavioral interventions may have potential for long‐term obesity prevention.
Abstract: More than 20% of US children between ages 2 and 5 years are overweight suggesting efforts to prevent obesity must begin earlier. This study tested the independent and combined effects of two behavioral interventions delivered to parents, designed to promote healthy infant growth in the first year. Mother-newborn dyads intending to breastfeed were recruited from a maternity ward. With a 2 × 2 design, 160 dyads were randomized into one of four treatment cells to receive both, one, or no interventions delivered at two nurse home visits. The first intervention ("Soothe/Sleep") instructed parents on discriminating between hunger and other sources of infant distress. Soothing strategies were taught to minimize feeding for non-hunger-related fussiness and to prolong sleep duration, particularly at night. The second intervention ("Introduction of Solids") taught parents about hunger and satiety cues, the timing for the introduction of solid foods, and how to overcome infants' initial rejection of healthy foods through repeated exposure. A total of 110 mother-infant dyads completed the year-long study. At 1 year, infants who received both interventions had lower weight-for-length percentiles (P = 0.009). Participants receiving both interventions had a mean weight-for-length in the 33rd percentile; in contrast, those in other study groups were higher first intervention only--50th percentile; second intervention only--56th percentile; control group--50th percentile).This suggests that multicomponent behavioral interventions may have potential for long-term obesity prevention (ClinicalTrials.gov number, NCT00359242).

Journal ArticleDOI
01 Mar 2011-Obesity
TL;DR: It is demonstrated that subclinical endotoxemia is associated with systemic and AT inflammation in obese pregnant women and recognition of bacterial pathogens may contribute to the combined dysfunction of innate immunity and the metabolic systems in AT.
Abstract: Obese pregnant women develop severe insulin resistance and enhanced systemic and placental inflammation, suggesting associated modifications of endocrine and immune functions. Activation of innate immunity by endotoxins/lipopolysaccharides (LPS) has been proposed as a mechanism for enhancing metabolic alterations in disorders with insulin resistance. The aim of this study was to characterize the immune responses developed by the adipose tissue (AT) and their potential links to maternal endotoxemia in pregnancy with obesity. Blood and subcutaneous abdominal AT were obtained from 120 lean and obese women (term pregnancy) recruited at delivery. Gene expression was assessed in AT and stromal vascular cells isolated from a subset of 24 subjects from the same cohort. Doubling of plasma endotoxin concentrations indicated subclinical endotoxemia in obese compared with lean women. This was associated with significant increase in systemic C-reactive protein and interleukin-6 (IL-6) but not tumor necrosis factor-α (TNF-α) concentrations. AT inflammation was characterized by accumulation of CD68(+) macrophages with a threefold increased gene expression of the macrophage markers CD68, EMR1, and CD14. Gene expression for cytokines IL-6, TNF-α, IL-8, and monocyte chemotactic protein-1 (MCP1) and for LPS-sensing CD14, toll-like receptor 4 (TLR4), translocating chain-associated membrane protein 2 was 2.5-5-fold higher in stromal cells of obese compared to lean. LPS-treated cultured stromal cells of obese women expressed a 5-16-fold stimulation of the same cytokines upregulated in vivo. Our data demonstrate that subclinical endotoxemia is associated with systemic and AT inflammation in obese pregnant women. Recognition of bacterial pathogens may contribute to the combined dysfunction of innate immunity and the metabolic systems in AT.

Journal ArticleDOI
01 Mar 2011-Obesity
TL;DR: Findings suggest a possible role for adiposity in WM dysfunction and associated cognitive deficits, and an interaction between obesity and aging processes on certain WM tracts in otherwise healthy adults.
Abstract: Existing work demonstrates that obesity is independently associated with cognitive dysfunction and macrostructural brain changes; however, little is known about the association between obesity and white matter (WM) integrity. We explore this relationship in a large cohort of otherwise healthy subjects. The present study classified 103 adult participants from the Brain Resource International Database between 21 and 86 years of age without history of neurological, medical, or psychiatric illness according to BMI (normal weight, overweight, obese) and subjected them to diffusion tensor imaging (DTI). Resulting fractional anisotropy (FA) indexes for the corpus callosum and fornix were examined in relation to BMI and age in a multiple regression framework. Results indicated that increasing BMI was independently associated with lower FA in the genu, splenium, and fornix, and a BMI × age interaction emerged for FA in the splenium and body of the corpus callosum. When categorized, obese persons demonstrated lower FA than normal and overweight persons for all WM indexes, but no FA differences emerged between overweight and normal persons. Results indicate both a direct association between obesity and reduced WM tract integrity and an interaction between obesity and aging processes on certain WM tracts in otherwise healthy adults. While such findings suggest a possible role for adiposity in WM dysfunction and associated cognitive deficits, prospective studies are needed to clarify the nature of these relationships and elucidate underlying mechanisms.

Journal ArticleDOI
01 Apr 2011-Obesity
TL;DR: The diabetogenic effect of low‐dose exposure to POPs might be more complicated than a simple obesogenic effect, according to a cohort of obese and lean adult men and women.
Abstract: Persistent organic pollutants (POPs) are endocrine-disrupting chemicals associated with the development of the metabolic syndrome and type 2 diabetes. In humans, little is known about their role in the potential origin of obesity. This study aims to assess the associations between serum levels of POPs and the prevalence of obesity in a cohort of obese and lean adult men and women. POP serum samples were investigated cross-sectionally in 98 obese and 47 lean participants, aged ≥18 years. Serum samples were analyzed for the presence of polychlorinated biphenyl (PCB) congeners 153, 138, 180, and 170 and for the organochlorine pesticides, dichloro-diphenyl-dichloroethylene (pp-DDE), and β-hexachlorocyclohexane (βHCH). We established a significant negative correlation between BMI, waist, fat mass percentage, total and subcutaneous abdominal adipose tissue, and serum levels of PCB 153, 180, 170, and the sumPCBs. For βHCH, we demonstrated a positive correlation with BMI, waist, fat mass percentage, and total and subcutaneous abdominal adipose tissue. PCBs 180, 170, and the sum of PCBs correlated significantly negative with homeostasis model assessment for insulin resistance (HOMA(IR)). βHCH correlated significantly positively with HOMA(IR). A strong correlation was established between all POP serum levels and age. We established a positive relationship between high serum levels of βHCH and BMI and HOMA(IR), whereas serum PCB levels were inversely correlated with BMI and HOMA(IR). Combined, these results suggest that the diabetogenic effect of low-dose exposure to POPs might be more complicated than a simple obesogenic effect.

Journal ArticleDOI
01 May 2011-Obesity
TL;DR: The intervention showed positive influences on physical activity and screen time, but not on diet, and it is feasible to adapt an obesity prevention program to be taught by classroom teachers.
Abstract: The preschool years offer an opportunity to interrupt the trajectory toward obesity in black children. The Hip-Hop to Health Jr. Obesity Prevention Effectiveness Trial was a group-randomized controlled trial assessing the feasibility and effectiveness of a teacher-delivered weight control intervention for black preschool children. The 618 participating children were enrolled in 18 schools administered by the Chicago Public Schools. Children enrolled in the nine schools randomized to the intervention group received a 14-week weight control intervention delivered by their classroom teachers. Children in the nine control schools received a general health intervention. Height and weight, physical activity, screen time, and diet data were collected at baseline and postintervention. At postintervention, children in the intervention schools engaged in more moderate-to-vigorous physical activity (MVPA) than children in the control schools (difference between adjusted group means = 7.46 min/day, P = 0.02). Also, children in the intervention group had less total screen time (-27.8 min/day, P = 0.05). There were no significant differences in BMI, BMI Z score, or dietary intake. It is feasible to adapt an obesity prevention program to be taught by classroom teachers. The intervention showed positive influences on physical activity and screen time, but not on diet. Measuring diet and physical activity in preschool children remains a challenge, and interventions delivered by classroom teachers require both intensive initial training and ongoing individualized supervision.

Journal ArticleDOI
01 Nov 2011-Obesity
TL;DR: In conclusion, CIH exacerbates IR and induces steatohepatitis in DIO mice, suggesting that CIH may account for metabolic dysfunction in obesity.
Abstract: Obesity causes insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD), but the relative contribution of sleep apnea is debatable. The main aim of this study is to evaluate the effects of chronic intermittent hypoxia (CIH), a hallmark of sleep apnea, on IR and NAFLD in lean mice and mice with diet-induced obesity (DIO). Mice (C57BL/6J), 6–8 weeks of age were fed a high fat (n = 18) or regular (n = 16) diet for 12 weeks and then exposed to CIH or control conditions (room air) for 4 weeks. At the end of the exposure, fasting (5 h) blood glucose, insulin, homeostasis model assessment (HOMA) index, liver enzymes, and intraperitoneal glucose tolerance test (1 g/kg) were measured. In DIO mice, body weight remained stable during CIH and did not differ from control conditions. Lean mice under CIH were significantly lighter than control mice by day 28 (P = 0.002). Compared to lean mice, DIO mice had higher fasting levels of blood glucose, plasma insulin, the HOMA index, and had glucose intolerance and hepatic steatosis at baseline. In lean mice, CIH slightly increased HOMA index (from 1.79 ± 0.13 in control to 2.41 ± 0.26 in CIH; P = 0.05), whereas glucose tolerance was not affected. In contrast, in DIO mice, CIH doubled HOMA index (from 10.1 ± 2.1 in control to 22.5 ± 3.6 in CIH; P < 0.01), and induced severe glucose intolerance. In DIO mice, CIH induced NAFLD, inflammation, and oxidative stress, which was not observed in lean mice. In conclusion, CIH exacerbates IR and induces steatohepatitis in DIO mice, suggesting that CIH may account for metabolic dysfunction in obesity.

Journal ArticleDOI
01 Mar 2011-Obesity
TL;DR: Free‐fatty acids can activate endoplasmic reticulum (ER) stress pathway by examination of ER stress sensor activation and marker gene expression and results indicate that ER stress pathway is a key mediator for FFA‐induced inflammation and insulin resistance in adipocytes with PERK and IKKβ as the critical signaling components.
Abstract: Free-fatty acids (FFAs) are well-characterized factor for causing production of inflammatory factors and insulin resistance in adipocytes. Using cultured adipocytes, we demonstrate that FFAs can activate endoplasmic reticulum (ER) stress pathway by examination of ER stress sensor activation and marker gene expression. Chemical chaperone tauroursodeoxycholic acid (TUDCA) can reduce FFA-induced adipocyte inflammation and improve insulin signaling whereas overexpression of spliced X-box protein 1 (XBP-1s) only attenuates FFA-induced inflammation. PKR-like eukaryotic initiation factor 2α kinase (PERK) is one of the three major ER stress sensor proteins and deficiency of PERK alleviates FFA-induced inflammation and insulin resistance. The key downstream target of FFA-induced ER stress is IκB kinase β (IKKβ), a master kinase for regulating expression of inflammatory genes. Deficiency of PERK attenuates FFA-induced activation of IKKβ and deficiency of IKKβ alleviates FFA-induced inflammation and insulin resistance. Consistently, overexpression of IKKβ in 3T3-L1 CAR adipocytes causes inflammation and insulin resistance. In addition, IKKβ overexpression has profound effect on adipocyte lipid metabolism, including inhibition of lipogenesis and promotion of lipolysis. Furthermore, increased endogenous IKKβ expression and activation is also observed in isolated primary adipocytes from mice injected with lipids or fed on high-fat diet (HFD) acutely. These results indicate that ER stress pathway is a key mediator for FFA-induced inflammation and insulin resistance in adipocytes with PERK and IKKβ as the critical signaling components.

Journal ArticleDOI
01 May 2011-Obesity
TL;DR: It is found that an elevated BMI is associated with decreased rCBF in the prefrontal cortex of a healthy cohort, indicating that elevated BMI may be a risk factor for decreased prefrontal cortex function and potentially impaired executive function.
Abstract: Obesity is a risk factor for stroke and neurodegenerative disease. Excess body fat has been linked to impaired glucose metabolism, insulin resistance, and impulsivity and may be a precursor to decline in attention and executive cognitive function. Here, we investigated the effects of high BMI on regional cerebral blood flow (rCBF) using single photon emission computed tomography (SPECT) imaging in healthy subjects. A total of 16 adult men and 20 adult women were recruited from the community between January 2003 and July 2009 as part of a healthy brain study (HBS) conducted at the Amen Clinics, a private medical facility. Participants in the study were screened to exclude medical, neurological, and psychiatric conditions, including substance abuse. Subjects were categorized as normal or overweight according to BMI. Using a two sample t-test, we determined the effects of BMI on rCBF in normal vs. overweight subjects. Subjects were matched for age and gender. Statistical parametric mapping (SPM) revealed a higher BMI in healthy individuals that is associated with decreased rCBF in Broadmann areas 8, 9, 10, 11, 32, and 44, brain regions involved in attention, reasoning, and executive function (P < 0.05, corrected for multiple comparisons). We found that an elevated BMI is associated with decreased rCBF in the prefrontal cortex of a healthy cohort. These results indicate that elevated BMI may be a risk factor for decreased prefrontal cortex function and potentially impaired executive function.

Journal ArticleDOI
01 Jul 2011-Obesity
TL;DR: It is shown that hepatic glycogen accumulates H2 after oral administration of H2‐water, explaining why consumption of even a small amount of H1N1 over a short span time efficiently improves various disease models.
Abstract: Recent extensive studies have revealed that molecular hydrogen (H 2 ) has great potential for improving oxidative stress-related diseases by inhaling H 2 gas, injecting saline with dissolved H 2 , or drinking water with dissolved H 2 (H 2 -water); however, little is known about the dynamic movement of H 2 in a body. First, we show that hepatic glycogen accumulates H 2 after oral administration of H 2 -water, explaining why consumption of even a small amount of H 2 over a short span time efficiently improves various disease models. This finding was supported by an in vitro experiment in which glycogen solution maintained H 2 . Next, we examined the benefit of ad libitum drinking H 2 -water to type 2 diabetes using db/db obesity model mice lacking the functional leptin receptor. Drinking H 2 -water reduced hepatic oxidative stress, and significantly alleviated fatty liver in db/db mice as well as high fat-diet-induced fatty liver in wild-type mice. Long-term drinking H 2 -water significantly controlled fat and body weights, despite no increase in consumption of diet and water. Moreover, drinking H 2 -water decreased levels of plasma glucose, insulin, and triglyceride, the effect of which on hyperglycemia was similar to diet restriction. To examine how drinking H 2 -water improves obesity and metabolic parameters at the molecular level, we examined gene-expression profiles, and found enhanced expression of a hepatic hormone, fibroblast growth factor 21 (FGF21), which functions to enhance fatty acid and glucose expenditure. Indeed, H 2 stimulated energy metabolism as measured by oxygen consumption. The present results suggest the potential benefit of H 2 in improving obesity, diabetes, and metabolic syndrome.

Journal ArticleDOI
01 Jan 2011-Obesity
TL;DR: An intensive intervention that includes child behavior management strategies to improve healthy eating and activity appears more promising in reducing preschool obesity than a low intensity intervention that is typical of treatment that could be delivered in primary care.
Abstract: We evaluated the efficacy of a 6-month clinic and home-based behavioral intervention (Learning about Activity and Understanding Nutrition for Child Health; LAUNCH) to reduce obesity in preschool children ≥95th BMI percentile compared to enhanced standard of care (Pediatrician Counseling; PC). LAUNCH was a family-based behavioral intervention that taught parents to use child behavior management strategies to increase healthy eating and activity for their children and themselves. PC presented the same diet and activity recommendations, but was delivered in a one-time PC session. Eighteen children aged 2–5 years (mean 4.71 ± 1.01) with an average BMI percentile of 98 (±1.60) and an overweight parent were randomized to LAUNCH or PC. Assessments were conducted at baseline, 6 months (end of LAUNCH treatment) and 12 months (6 months following LAUNCH treatment). LAUNCH showed a significantly greater decrease on the primary outcomes of child at month 6 (post-treatment) BMI z (−0.59 ± 0.17), BMI percentile (−2.4 ± 1.0), and weight gain (−2.7 kg ± 1.2) than PC and this difference was maintained at follow-up (month 12). LAUNCH parents also had a significantly greater weight loss (−5.5 kg ± 0.9) at month 6 and 12 (−8.0 kg ± 3.5) than PC parents. Based on the data from this small sample, an intensive intervention that includes child behavior management strategies to improve healthy eating and activity appears more promising in reducing preschool obesity than a low intensity intervention that is typical of treatment that could be delivered in primary care.