The obesity epidemic

Weight related health status of patients treated by dietitians in primary care practice: first results of a cohort study

Background

Overweight and obesity are common in the Netherlands: in 2006 51% of adult men and 42% of adult women were overweight; 10% of men and 12% of women were obese. Patients with overweight or obesity in the Netherlands are often referred to dietitians in primary care for weight loss treatment. We followed a prospective observational cohort to study the effectiveness of this treatment and present the baseline results in this article.

Methods

We invited dietitians throughout the country, who completed at baseline a questionnaire for each patient including weight, stature, waist circumference, age, gender, morbidities, medication, education level, ethnicity, referral, treatment expectations, history of previous weight loss attempts, and exercise.

Results

At baseline data from 1546 patients were obtained from 158 dietitians working in 26 practices. The majority (73%) of patients were obese (BMI ≥ 30 kg/m²); and 10% had a BMI of 40 kg/m² or more. The majority of patients (94%) had a high to extremely high weight related health risk (WRHR): (BMI 25–30 kg/m² with comorbidities, or BMI 30–35 kg/m² without comorbidities, up to BMI ≥35 with comorbidities and BMI ≥40 with or without comorbidities). More than half (57%) had comorbidities and a long history of weight loss attempts. An extremely high WRHR was seen in 24.5% of the sample. Patients with very high to extremely high WRHR often had type 2 diabetes mellitus; hypertension; dyslipidaemia; osteo arthritis; and sleep apnoea. Patients of middle and old age had a higher risk for very high and extremely high WRHR. Those with other comorbidities and those who asked for referral themselves had a lower risk.

Conclusion

The study was effective in recruiting dietitians to participate. The sample is representative for dietitians working in primary care. The majority of patients (94%) had a high to extremely high weight related health risk (WRHR).

Analysis of fall injuries by body mass index

OBJECTIVE

To examine the association of body mass index (BMI) and fall injuries.

METHODS

Data were derived from the 2010 Behavioral Risk Factor Surveillance System and included subjects aged 45 years and older from Texas. The outcome was self-reported falls that resulted in injury to the respondents. Analysis of fall injuries by BMI was conducted and standard errors, 95% confidence intervals (CIs), and coefficients of variation were reported. Complex sample multivariate Poisson regression was used to examine the association of BMI and fall injuries.

RESULTS

A total of 18,077 subjects were surveyed in 2010, and 13,235 subjects were aged 45 years old and older. The mean BMI was higher (29.94 vs 28.32 kg/m(2)) among those who reported fall injuries compared with those who did not. The fall injuries reported by obese respondents (relative risk [RR] 1.67) were found to be significantly (P = 0.031) higher compared with normal-weight respondents in the multivariate regression. Other risk factors that had significant association with fall injuries (when adjusted for BMI) were activity limitations (RR 5.00, 95% CI 3.36-7.46) compared with no limitations, and not having formal employment (homemaker: RR 2.68, 95% CI 1.33-5.37; unable to work: RR 5.01, 95% CI 1.87-13.29; out of work and students: RR 3.21, 95% CI 1.41-7.29) compared with the employed population.

CONCLUSIONS

There is a significant association between obesity and fall injuries in adults aged 45 years old and older in Texas. Interventions in fall prevention, although generally targeted at present to older adults, also should take into account the weight status of the subjects.

Effects of acute resistance exercise on muscle damage and perceptual measures between men who are lean and obese

The purpose of this investigation was to assess indices of muscle damage and psychological stress between young, untrained, lean, and obese men. Using a between-subject design, 19 young men (9 lean men [age, 20.1 ± 2.1 years; body mass, 71.7 ± 5.8 kg; height, 177.8 ± 8.7 cm; body fat (BF), 14.7 ± 3.5%], 5 World Health Organization [WHO] class 1 obese men [age, 21.6 ± 2.5 years; body mass, 97.8 ± 8.6 kg; height, 176.3 ± 3.7 cm; BF, 34.7 ± 3.0%], and 5 WHO class 2 or 3 men [age, 20.0 ± 1.4 years; body mass, 120.8 ± 10.5 kg; height, 177.7 ± 5.2 cm; BF, 40.5 ± 5.8%]) volunteered and completed an acute resistance exercise (RE) protocol (6 exercises performed for 3 sets of 10 repetitions at an intensity of 85-95% of a 10 repetition maximum). Plasma myoglobin and serum creatine kinase were obtained before and immediately after exercise, and in recovery (at +110 minutes and +24 hours). Perceptual measures including rating of perceived exertion, pain and soreness, fatigue, and general soreness were assessed at different time points (during exercise for rating of perceived exertion, and for the fatigue and soreness measures before, immediately after, and at 24 hours of recovery from exercise). The primary findings of this investigation were that lean and obese, sedentary, young men do not significantly differ from each other in terms of indirect, humoral measures of muscle damage, or perceptual scales in response to a moderate-intensity acute RE bout, despite using significantly more exercise volume relative to fat mass (FM). We conclude that excess FM during daily activities of life provides a protective effect for muscle damage. When strength training individuals who are obese, practitioners should be aware of how excess FM affects muscle damage and total volume. But these considerations do not preclude individuals who are obese from using well-designed RE workouts which use free-weight, multijoint movements that stimulate all of the major muscle groups.

Diet and diet combined with chronic aerobic exercise decreases body fat mass and alters plasma and adipose tissue inflammatory markers in obese women

The purpose of this study was to investigate the effect of 6 months aerobic exercise and diet alone or in combination on markers of inflammation (MOI) in circulation and in adipose abdominal tissue (AT) in obese women. Thirty obese subjects were randomized into a 24-week intervention: (1) exercise (EX), (2) diet (DI), and (3) exercise and diet (EXD). Blood samples were collected at baseline, after 12 and 24 weeks. AT biopsies were obtained only at baseline and after 24 weeks. In the EXD and DI groups, the fat loss was after 12 weeks was -13.74 and -7.8 % (P < 0.01) and after 24 weeks was -21.82 and -17 % (P < 0.01) with no changes in the EX group. After 12 and 24 weeks, maximal oxygen consumption (VO2max) was increased by 21.81-39.54 % (P < 0.05) in the EXD group and 18.09-40.95 % in the EX group with no changes in the DI group. In the EXD and DI groups, circulating levels of tumor necrosis factor α and interleukin 6 were decreased after 24 weeks for both groups (P < 0.01). No changes in the EX group. Homeostatic model assessment for insulin resistance decreased (P < 0.05) only after 24 weeks in the EXD group. In AT biopsies, subjects in the EXD and DI groups exhibited a significant decrease in MO (P < 0.01 for all). No changes in AT biopsies were found in the EX group. In conclusion, chronic aerobic exercise was found to have no effects on circulating and AT MOI despite an increased VO2max. Rather important body composition modifications were found to have beneficial effects on circulating and AT MOI in these obese women.

Meal pattern of male rats maintained on amino acid supplemented diets: the effect of tryptophan, lysine, arginine, proline and threonine

The macronutrient composition of the diet has been shown to affect food intake, with proteins having distinct effects. The present study investigated the effect of diet supplementation with individual amino acids (tryptophan, lysine, arginine, proline and threonine) on meal pattern among male rats. Meal pattern and body weight were monitored for two weeks. Proline and threonine had minimal effects on meal pattern, while the most pronounced changes were observed in the tryptophan group. Both tryptophan and lysine decreased overall food intake, which was translated into a reduction in body weight. The reduced food intake of the tryptophan group was associated with an increase in meal size, intermeal intervals (IMI) and meal time and a decrease in meal number. The decrease in the food intake of the lysine group was associated with a reduction in both IMI and meal number, and this was accompanied by an increase in meal time. Arginine increased meal number, while decreasing IMI. Proline and threonine had a minimal effect on meal pattern. Lysine seems to increase satiety, and arginine seems to decrease it, while tryptophan seems to increase satiety and decrease satiation. Accordingly, changes in meal patterns are associated with the type of amino acid added to the diet.

Pseudomonas aeruginosa biofilms: mechanisms of immune evasion

The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.

Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge

Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (body mass index difference >3 kg/m(2)). Nine concordant monozygotic pairs were examined as control pairs. Fecal samples were analyzed to assess diversity of the major bacterial groups by using 5 different validated bacterial group specific denaturing gradient gel electrophoresis methods. No differences in fecal bacterial diversity were detected when comparing co-twins discordant for weight (ANOVA, P<0.05). We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity. Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially (paired t tests, FDR q<0.05). We also found that specific bacterial groups were associated with postprandial changes of specific metabolites. Our findings underline important roles of genetic and early life factors in the regulation of postprandial metabolite levels.

DNA methylation of the LY86 gene is associated with obesity, insulin resistance, and inflammation

BACKGROUND

Previous genome-wide association studies (GWAS) have identified a large number of genetic variants for obesity and its related traits, representing a group of potential key genes in the etiology of obesity. Emerging evidence suggests that epigenetics may play an important role in obesity. It has not been explored whether the GWAS-identified loci contribute to obesity through epigenetics (e.g., DNA (deoxyribonucleic acid) methylation) in addition to genetics.

METHOD

A multi-stage cross-sectional study was designed. We did a literature search and identified 117 genes discovered by GWAS for obesity and its related traits. Then we analyzed whether the methylation levels of these genes were also associated with obesity in two genome-wide methylation panels. We examined an initial panel of seven adolescent obese cases and seven age-matched lean controls, followed by a second panel of 48 adolescent obese cases and 48 age- and gender-matched lean controls. The validated CpG sites were further replicated in two independent replication panels of youth (46 vs. 46 and 230 cases vs. 413 controls, respectively) and a general population of youth, including 703 healthy subjects.

RESULTS

One CpG site in the lymphocyte antigen 86 (LY86) gene, which showed higher methylation in the obese in both the initial (p = .009) and second genome-wide DNA methylation panel (p = .008), was further validated in both replication panels (meta p = .00016). Moreover, in the general population of youth, the methylation levels of this region were significantly correlated with adiposity indices (p ≤ .02), insulin resistance (p = .001), and inflammatory markers (p < .001).

CONCLUSION

By focusing on recent GWAS findings in genome-wide methylation profiles, we identified a solid association between LY86 gene DNA methylation and obesity.

Impact of biofeedback on self-efficacy and stress reduction in obesity: a randomized controlled pilot study

Biofeedback application is an evidence-based technique to induce relaxation. A primary mechanism of action is the improvement of self-efficacy, which is needed to facilitate the translation of health behavioral intentions into action. Obesity is often associated with low self-efficacy and dysfunctional eating patterns, including comfort eating as an inexpedient relaxation technique. This is the first study investigating the effects of biofeedback on self-efficacy and relaxation in obesity. In the present experiment, 31 women, mean body mass index 35.5 kg/m², were randomized to a food-specific biofeedback paradigm, a non-specific relaxation biofeedback paradigm, or a waiting list control. Eight sessions of biofeedback of the electrodermal activity were performed while presenting either a challenging food stimulus or a non-specific landscape stimulus. Self-efficacy, stress, ability to relax, eating behavior, and electrodermal activity were assessed before, directly after, and 3 months after the intervention. The food-specific biofeedback predominantly showed effects on food-related self-efficacy and perceived stress. The non-specific relaxation biofeedback showed effects on the ability to relax. Self-reported improvements were confirmed by corresponding decrease in the electrodermal reaction to food stimuli. Biofeedback treatment is effective in improving self-efficacy in individuals with obesity and might therefore be a valuable additional intervention in obesity treatment.

MicroRNAs in bovine adipogenesis: genomic context, expression and function

Background

MicroRNAs (miRNAs) are small non-coding RNAs found to regulate several biological processes including adipogenesis. Understanding adipose tissue regulation is critical for beef cattle as fat is an important determinant of beef quality and nutrient value. This study analyzed the association between genomic context characteristics of miRNAs with their expression and function in bovine adipose tissue. Twenty-four subcutaneous adipose tissue biopsies were obtained from eight British-continental crossbred steers at 3 different time points. Total RNA was extracted and miRNAs were profiled using a miRNA microarray with expression further validated by qRT-PCR.

Results

A total of 224 miRNAs were detected of which 155 were expressed in all steers (n = 8), and defined as the core miRNAs of bovine subcutaneous adipose tissue. Core adipose miRNAs varied in terms of genomic location (59.5% intergenic, 38.7% intronic, 1.2% exonic, and 0.6% mirtron), organization (55.5% non-clustered and 44.5% clustered), and conservation (49% highly conserved, 14% conserved and 37% poorly conserved). Clustered miRNAs and highly conserved miRNAs were more highly expressed (p < 0.05) and had more predicted targets than non-clustered or less conserved miRNAs (p < 0.001). A total of 34 miRNAs were coordinately expressed, being part of six identified relevant networks. Two intronic miRNAs (miR-33a and miR-1281) were confirmed to have coordinated expression with their host genes, transcriptional factor SREBF2 and EP300 (a transcriptional co-activator of transcriptional factor C/EBPα), respectively which are involved in lipid metabolism, suggesting these miRNAs may also play a role in regulation of bovine lipid metabolism/adipogenesis. Furthermore, a total of 17 bovine specific miRNAs were predicted to be involved in the regulation of energy balance in adipose tissue.

Conclusions

These findings improve our understanding on the behavior of miRNAs in the regulation of bovine adipogenesis and fat metabolism as it reveals that miRNA expression patterns and functions are associated with miRNA genomic location, organization and conservation.

Improved metabolic phenotype of hypothalamic PTP1B-deficiency is dependent upon the leptin receptor

Protein tyrosine phosphatase 1B (PTP1B) is a known regulator of central metabolic signaling, and mice with whole brain-, leptin receptor (LepRb) expressing cell-, or proopiomelanocortin neuron-specific PTP1B-deficiency are lean, leptin hypersensitive, and display improved glucose homeostasis. However, whether the metabolic effects of central PTP1B-deficiency are due to action within the hypothalamus remains unclear. Moreover, whether or not these effects are exclusively due to enhanced leptin signaling is unknown. Here we report that mice with hypothalamic PTP1B-deficiency (Nkx2.1-PTP1B(-/-)) display decreased body weight and adiposity on high-fat diet with no associated improvements in glucose tolerance. Consistent with previous reports, we find that hypothalamic deletion of the LepRb in mice (Nkx2.1-LepRb(-/-)) results in extreme hyperphagia and obesity. Interestingly, deletion of hypothalamic PTP1B and LepRb (Nkx2.1-PTP1B(-/-):LepRb(-/-)) does not rescue the hyperphagia or obesity of Nkx2.1-LepRb(-/-) mice, suggesting that hypothalamic PTP1B contributes to the central control of energy balance through a leptin receptor-dependent pathway.

Patient perception of ideal body weight and the effect of body mass index

OBJECTIVE

Despite much effort, obesity remains a significant public health problem. One of the main contributing factors is patients' perception of their target ideal body weight. This study aimed to assess this perception.

METHODS

The study took place in an urban area, with the majority of participants in the study being Hispanic (65.7%) or African-American (28.0%). Patients presented to an outpatient clinic were surveyed regarding their ideal body weight and their ideal BMI calculated. Subsequently they were classified into different categories based on their actual measured BMI. Their responses for ideal BMI were compared.

RESULTS

In 254 surveys, mean measured BMI was 31.71 ± 8.01. Responses to ideal BMI had a range of 18.89-38.15 with a mean of 25.96 ± 3.25. Mean (±SD) ideal BMI for patients with a measured BMI of <18.5, 18.5-24.9, 25-29.9, and ≥30 was 20.14 ± 1.46, 23.11 ± 1.68, 25.69 ± 2.19, and 27.22 ± 3.31, respectively. These differences were highly significant (P < 0.001, ANOVA).

CONCLUSIONS

Most patients had an inflated sense of their target ideal body weight. Patients with higher measured BMI had higher target numbers for their ideal BMI. Better education of patients is critical for obesity prevention programs.

Elucidation of molecular mechanisms of physiological variations between bovine subcutaneous and visceral fat depots under different nutritional regimes

Adipose tissue plays a critical role in energy homeostasis and metabolism. There is sparse understanding of the molecular regulation at the protein level of bovine adipose tissues, especially within different fat depots under different nutritional regimes. The objective of this study was to analyze the differences in protein expression between bovine subcutaneous and visceral fat depots in steers fed different diets and to identify the potential regulatory molecular mechanisms of protein expression. Subcutaneous and visceral fat tissues were collected from 16 British-continental steers (15.5 month old) fed a high-fat diet (7.1% fat, n=8) or a control diet (2.7% fat, n=8). Protein expression was profiled using label free quantification LC-MS/MS and expression of selected transcripts was evaluated using qRT-PCR. A total of 682 proteins were characterized and quantified with fat depot having more impact on protein expression, altering the level of 51.0% of the detected proteins, whereas diet affected only 5.3%. Functional analysis revealed that energy production and lipid metabolism were among the main functions associated with differentially expressed proteins between fat depots, with visceral fat being more metabolically active than subcutaneous fat as proteins associated with lipid and energy metabolism were upregulated. The expression of several proteins was significantly correlated to subcutaneous fat thickness and adipocyte size, indicating their potential as adiposity markers. A poor correlation (r=0.245) was observed between mRNA and protein levels for 9 genes, indicating that many proteins may be subjected to post-transcriptional regulation. A total of 8 miRNAs were predicted to regulate more than 20% of lipid metabolism proteins differentially expressed between fat depots, suggesting that miRNAs play a role in adipose tissue regulation. Our results show that proteomic changes support the distinct metabolic and physiological characteristics observed between subcutaneous and visceral adipose tissue depots in cattle.

Relationship between overweight and health-related quality of life in secondary school children in Fiji: results from a cross-sectional population-based study

OBJECTIVE

To investigate the relationship between excess weight (overweight and obesity) and health-related quality of life (HRQoL) in a sample of secondary school children in Fiji, by gender, age and ethnicity.

METHODS

The study comprised 8947 children from forms 3-6 (age 12-18 years) in 18 secondary schools on Viti Levu, the main island of Fiji. Body mass index (BMI) was calculated from measured height and weight, and weight status was classified according to the International Obesity Task Force recommendations. HRQoL was measured by the self-report version of the Pediatric Quality of Life Inventory 4.0.

RESULTS

HRQoL was similar in children with obesity and normal weight. Generally, this was replicated when analyzed separately by gender and ethnicity, but age stratification revealed disparities. In 12-14-year-old children, obesity was associated with better HRQoL, owing to better social and school functioning and well-being, and in 15-18-year olds with poorer HRQoL, owing to worse physical, emotional and social functioning and well-being (Cohen's d 0.2-0.3). Children with a BMI in the overweight range also reported a slightly lower HRQoL than children with a BMI in the normal weight range, but although statistically significant, the size of this difference was trivial (Cohen's d <0.2).

DISCUSSION

The results suggest that, overall there is no meaningful negative association between excess weight and HRQoL in secondary school children in Fiji. This is in contradiction to the negative relationship between excess weight and HRQoL shown in studies from other countries and cultures. The assumption that a large body size is associated with a lower quality of life cannot be held universally. Although a generally low HRQoL among children in Fiji may be masking or overriding the potential effect of excess weight on HRQoL, socio-economic and/or socio-cultural factors, may help to explain these relationships.

Influence of physical activity and nutrition on obesity-related immune function

Research examining immune function during obesity suggests that excessive adiposity is linked to impaired immune responses leading to pathology. The deleterious effects of obesity on immunity have been associated with the systemic proinflammatory profile generated by the secretory molecules derived from adipose cells. These include inflammatory peptides, such as TNF- α , CRP, and IL-6. Consequently, obesity is now characterized as a state of chronic low-grade systemic inflammation, a condition considerably linked to the development of comorbidity. Given the critical role of adipose tissue in the inflammatory process, especially in obese individuals, it becomes an important clinical objective to identify lifestyle factors that may affect the obesity-immune system relationship. For instance, stress, physical activity, and nutrition have each shown to be a significant lifestyle factor influencing the inflammatory profile associated with the state of obesity. Therefore, the purpose of this review is to comprehensively evaluate the impact of lifestyle factors, in particular psychological stress, physical activity, and nutrition, on obesity-related immune function with specific focus on inflammation.

Patients with chronic pulmonary disease

Chronic pulmonary disease is common among the surgical population and the importance of a thorough and detailed preoperative assessment is monumental for minimizing morbidity and mortality and reducing the risk of perioperative pulmonary complications. These comorbidities contribute to pulmonary postoperative complications, including atelectasis, pneumonia, and respiratory failure, and can predict long-term mortality. The important aspects of the preoperative assessment for patients with chronic pulmonary disease, and the value of preoperative testing and smoking cessation, are discussed. Specifically discussed are preoperative pulmonary assessment and management of patients with chronic obstructive pulmonary disease, asthma, restrictive lung disease, obstructive sleep apnea, and obesity.

QTL-based association analyses reveal novel genes influencing pleiotropy of metabolic syndrome (MetS)

OBJECTIVE

Metabolic Syndrome (MetS) is a phenotype cluster predisposing to type 2 diabetes and cardiovascular disease. We conducted a study to elucidate the genetic basis underlying linkage signals for multiple representative traits of MetS that we had previously identified at two significant QTLs on chromosomes 3q27 and 17p12.

DESIGN AND METHODS

We performed QTL-specific genomic and transcriptomic analyses in 1,137 individuals from 85 extended families that contributed to the original linkage. We tested in SOLAR association of MetS phenotypes with QTL-specific haplotype-tagging SNPs as well as transcriptional profiles of peripheral blood mononuclear cells (PBMCs).

RESULTS

SNPs significantly associated with MetS phenotypes under the prior hypothesis of linkage mapped to seven genes at 3q27 and seven at 17p12. Prioritization based on biologic relevance, SNP association, and expression analyses identified two genes: insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) at 3q27 and tumor necrosis factor receptor 13B (TNFRSF13B) at 17p12. Prioritized genes could influence cell-cell adhesion and adipocyte differentiation, insulin/glucose responsiveness, cytokine effectiveness, plasma lipid levels, and lipoprotein densities.

CONCLUSIONS

Using an approach combining genomic, transcriptomic, and bioinformatic data we identified novel candidate genes for MetS.

Weight loss-induced reduction in physical activity recovers during weight maintenance

BACKGROUND

Weight loss due to a negative energy balance is considered to be accompanied by a decrease in physical activity.

OBJECTIVE

The aim of this study was to investigate whether a decrease in physical activity is sustained during weight maintenance.

DESIGN

Subjects were 20 men and 31 women [mean (±SD) age: 42 ± 8 y; BMI (in kg/m(2)): 31.4 ± 2.8]. Weight loss was achieved by an 8-wk very-low-energy diet period, followed by 44 wk of weight maintenance. Physical activity measures were total energy expenditure expressed as a multiple of sleeping metabolic rate (PALSMR) and resting metabolic rate (PALRMR), activity-induced energy expenditure divided by body weight (AEE/kg), and activity counts measured by a triaxial accelerometer. Measurements took place at 0, 8, and 52 wk.

RESULTS

Body mass decreased significantly during the diet period (10.5 ± 3.8%, P < 0.001), and this reduction was sustained after 52 wk (6.0 ± 5.1%, P < 0.001). PALSMR and PALRMR decreased from 1.81 ± 0.23 and 1.70 ± 0.22, respectively, before the diet to 1.69 ± 0.20 and 1.55 ± 0.19 after the diet (P < 0.001) and increased again after weight maintenance to 1.85 ± 0.27 and 1.71 ± 0.23, respectively, compared with 8-wk measurements (P < 0.001). AEE/kg decreased from 0.043 ± 0.015 MJ/kg at baseline to 0.037 ± 0.014 MJ/kg after the diet (P < 0.001) and was higher after 52 wk (0.044 ± 0.17 MJ/kg) compared with after 8 wk (P < 0.001). Activity counts decreased from 1.64 ± 0.37 megacounts/d at baseline to 1.54 ± 0.35 megacounts/d after the diet (P < 0.05) and were higher after 52 wk (1.73 ± 0.49 megacounts/d) compared with 8 wk (P < 0.01).

CONCLUSION

A weight loss-induced reduction in physical activity returns to baseline values when weight loss is maintained. This trial was registered at clinicaltrials.gov as NCT01015508.

Obese patients undergoing total knee arthroplasty have distinct preoperative characteristics: an institutional study of 4718 patients

Obesity affects a disproportionate proportion of total knee arthroplasty (TKA) patients. Our study explores pre-operative characteristics between obese and non-obese patients undergoing TKA surgery. A cohort of 4718 osteoarthritic patients, undergoing primary TKA, was studied. Patients were stratified according to BMI classes. Each class was compared in terms of age, race, gender, level of education, insurance status, pre-operative WOMAC, SF-36, and Elixhauser comorbidities. There was a positive relationship between BMI and female gender, non-white race, Medicaid, private insurance, and self-pay. A negative relationship was observed between BMI and age, Medicare, WOMAC and SF-36. Obese TKA candidates differ from their non-obese counterparts in a number of demographic, socioeconomic, and clinical characteristics.

Dynamic regulation of hepatic lipid droplet properties by diet

Cytoplasmic lipid droplets (CLD) are organelle-like structures that function in neutral lipid storage, transport and metabolism through the actions of specific surface-associated proteins. Although diet and metabolism influence hepatic CLD levels, how they affect CLD protein composition is largely unknown. We used non-biased, shotgun, proteomics in combination with metabolic analysis, quantitative immunoblotting, electron microscopy and confocal imaging to define the effects of low- and high-fat diets on CLD properties in fasted-refed mice. We found that the hepatic CLD proteome is distinct from that of CLD from other mammalian tissues, containing enzymes from multiple metabolic pathways. The hepatic CLD proteome is also differentially affected by dietary fat content and hepatic metabolic status. High fat feeding markedly increased the CLD surface density of perilipin-2, a critical regulator of hepatic neutral lipid storage, whereas it reduced CLD levels of betaine-homocysteine S-methyltransferase, an enzyme regulator of homocysteine levels linked to fatty liver disease and hepatocellular carcinoma. Collectively our data demonstrate that the hepatic CLD proteome is enriched in metabolic enzymes, and that it is qualitatively and quantitatively regulated by diet and metabolism. These findings implicate CLD in the regulation of hepatic metabolic processes, and suggest that their properties undergo reorganization in response to hepatic metabolic demands.

The effect of parental socioeconomic class on children's body mass indices

OBJECTIVE

To assess the effect of education and economic status of parents on obesity in children.

METHODS

A cross-sectional survey was conducted in 2006 among school children in Riyadh, Saudi Arabia. A representative sample of 1243 (542 male and 701 female) children aged 6-16 years were contacted using multistage cluster sampling strategy. Social and demographic variables were collected using questionnaires completed by parents. Height and weight of the children were recorded by a trained team.

RESULTS

The mean body mass index for all children was 19.8±5.4. The prevalence rates of overweight and obesity were 21.1% and 12.7%, respectively. Overweight and obesity were more prevalent in males than in females. By multivariate analysis, children were more likely to be overweight if they were male (OR=0.6, p<0.01), 12 years of age (OR=3.79, p<0.01, compared to age 6 years), and if their families had higher income (OR=3.12, p<0.01, compared to families with low income). Being male (OR=0.545, p<0.01), aged 12 years (OR=3.9, p=0.005, compared to the age of 6), and having a mother who is more educated were determined to be significant risk factors for obesity in children. Mothers educated at university level were found to have a three-fold higher risk of having obese children(OR=3.4, p<0.01, compared to mothers with lower education levels).

CONCLUSIONS

Overweight and obesity among Saudi children is associated with educated mothers and higher family income. This finding calls for introducing interventions in health education for both children and parents.

Weight loss, weight maintenance, and adaptive thermogenesis

BACKGROUND

Diet-induced weight loss is accompanied by adaptive thermogenesis, ie, a disproportional or greater than expected reduction of resting metabolic rate (RMR).

OBJECTIVE

The aim of this study was to investigate whether adaptive thermogenesis is sustained during weight maintenance after weight loss.

DESIGN

Subjects were 22 men and 69 women [mean ± SD age: 40 ± 9 y; body mass index (BMI; in kg/m(2)): 31.9 ± 3.0]. They followed a very-low-energy diet for 8 wk, followed by a 44-wk period of weight maintenance. Body composition was assessed with a 3-compartment model based on body weight, total body water (deuterium dilution), and body volume. RMR was measured (RMRm) with a ventilated hood. In addition, RMR was predicted (RMRp) on the basis of the measured body composition: RMRp (MJ/d) = 0.024 × fat mass (kg) + 0.102 × fat-free mass (kg) + 0.85. Measurements took place before the diet and 8, 20, and 52 wk after the start of the diet.

RESULTS

The ratio of RMRm to RMRp decreased from 1.004 ± 0.077 before the diet to 0.963 ± 0.073 after the diet (P < 0.001), and the decrease was sustained after 20 wk (0.983 ± 0.063; P < 0.01) and 52 wk (0.984 ± 0.068; P < 0.01). RMRm/RMRp was correlated with the weight loss after 8 wk (P < 0.01), 20 wk (P < 0.05), and 52 wk (P < 0.05).

CONCLUSION

Weight loss results in adaptive thermogenesis, and there is no indication for a change in adaptive thermogenesis up to 1 y, when weight loss is maintained. This trial was registered at clinicaltrials.gov as NCT01015508.

Obesity in anesthesia and intensive care

Obesity is a global epidemic increasingly affecting management of anesthesia as well as intensive care medicine. Possible improvements in therapy require consideration of the specific pathophysiology of the obese, their concomitant diseases, and the complications associated with morbid obesity. Systematic assessment of perioperative risk factors is essential for an appropriate management. Paradoxically, overweight and moderately obese patients undergoing surgery have a lower risk when compared to patients with normal weight. The highest mortality and morbidity rates in this setting are reported for underweight and morbidly obese patients. The better chance of survival when compared to normal-weight individuals in the perioperative setting has been described the obesity paradox. In particular, the commitment of all involved physicians to improve all aspects of care will reduce the perioperative risk in obese patients. Physiological and pharmacological characteristics of the obese should also be considered. Furthermore, adequate technical equipment and practical skills of all members of the anesthesia team significantly contribute to risk reduction and therapeutic success in obese patients.

Perilipin-2-null mice are protected against diet-induced obesity, adipose inflammation, and fatty liver disease

The cytoplasmic lipid droplet (CLD) protein perilipin-2 (Plin2) is expressed in multiple nonadipose tissues, where it is thought to play a role in regulating their lipid storage properties. However, the extent to which Plin2 functions in nutrient utilization and metabolism, or how it influences the consequences of over-feeding, remains unclear. In this study, we demonstrate that the absence of Plin2 prevents high-fat diet(HFD)-induced obesity in male and female mice. This response is associated with increased formation of subcutaneous beige adipocyte cells with uncoupling protein 1 expression, and amelioration of inflammatory foci formation in white adipose tissue and steatosis in the liver. Experiments demonstrate that Plin2 loss results in reduced energy intake and increased physical activity in response to HFD feeding. Our study provides the first evidence that Plin2 contributes to HFD-induced obesity by modulating food intake, and that its absence prevents obesity-associated adipose tissue inflammatory foci and liver steatosis.

Obesity and psychotic disorders: uncovering common mechanisms through metabolomics

Primary obesity and psychotic disorders are similar with respect to the associated changes in energy balance and co-morbidities, including metabolic syndrome. Such similarities do not necessarily demonstrate causal links, but instead suggest that specific causes of and metabolic disturbances associated with obesity play a pathogenic role in the development of co-morbid disorders, potentially even before obesity develops. Metabolomics – the systematic study of metabolites, which are small molecules generated by the process of metabolism – has been important in elucidating the pathways underlying obesity-associated co-morbidities. This review covers how recent metabolomic studies have advanced biomarker discovery and the elucidation of mechanisms underlying obesity and its co-morbidities, with a specific focus on metabolic syndrome and psychotic disorders. The importance of identifying metabolic markers of disease-associated intermediate phenotypes – traits modulated but not encoded by the DNA sequence – is emphasized. Such markers would be applicable as diagnostic tools in a personalized healthcare setting and might also open up novel therapeutic avenues.

The oral microflora in obesity and type-2 diabetes

Background

Type 2 diabetes mellitus (T2DM) is prevalent in people with obesity. It has been proposed that these conditions are related to specific features of the microflora of the mouth and lower gastrointestinal (GI) tract. Hyperglycemia often resolves quickly after Roux-en-Y gastric bypass (RYGB) but the role of the GI microflora cannot be examined easily because of reduced intestinal mobility. We propose that the study of microorganisms present in the mouth of patients undergoing RYGB will contribute to our understanding of the role of bacteria in the pathogenesis of T2DM.

Objective

To conduct a feasibility study to examine differences in oral microbes in obese patients with and without T2DM and to determine whether it is feasible to measure changes after gastric bypass surgery.

Methods

Individuals with morbid obesity (n=29), of whom 13 had T2DM, were studied. Oral rinses, stool samples, and blood samples were obtained before RYGB, and oral rinses and blood samples were obtained at 2 and 12 weeks postsurgery.

Results

Prior to surgery, participants with T2DM had slightly higher total levels of oral bacteria than those without diabetes. Those with HbA1c > 6.5% had rather lower levels of Bifidobacteria in the mouth and stool. At 2 weeks post-RYGB, patients with T2DM were able to reduce or discontinue their hypoglycemic medications. Stool samples could not be obtained but oral rinses were readily available. The levels of oral Bifidobacteria had increased tenfold and levels of circulating endotoxin and tumor necrosis factor-alpha had decreased.

Conclusions

The study of oral bacteria before and after RYGB is feasible and should be tested in larger patient populations to increase our understanding of the role of microorganisms in the pathogenesis of obesity and T2DM.

Principles and results of bariatric surgery

Bariatric surgery is followed by substantial and durable weight loss and associated with it favorable metabolic effects far beyond those achieved by lifestyle modifications and pharmacological treatments. The perioperative and postoperative morbidity and mortality have decreased significantly over the years to the level that bariatric surgery now can compare with other frequently recommended and well-accepted procedures such as cholecystectomy and hysterectomy. In fact, the postoperative mortality risk of bariatric surgery is far lower than that of coronary artery bypass surgery but with significantly greater improvement in long-term mortality. Much of the improvement in perioperative morbidity and mortality can be attributed to advances in many components of the care chain such as the introduction of laparoscopic surgery, as well as establishment of a nationwide center of excellence network and required outcome reporting. Extensive evidence on safety and efficacy supports bariatric surgery as the standard of care for treatment of severe obesity. Bariatric surgery reduces the risk of global mortality, all-cause mortality and cardiovascular mortality when compared to obese control patients. Both gastric banding and gastric bypass seem to reduce mortality risk.

Protein v. carbohydrate intake differentially affects liking- and wanting-related brain signalling

Extreme macronutrient intakes possibly lead to different brain signalling. The aim of the present study was to determine the effects of ingesting high-protein v. high-carbohydrate food on liking and wanting task-related brain signalling (TRS) and subsequent macronutrient intake. A total of thirty female subjects (21·6 (sd 2·2) years, BMI 25·0 (sd 3·7) kg/m2) completed four functional MRI scans: two fasted and two satiated on two different days. During the scans, subjects rated all food items for liking and wanting, thereby choosing the subsequent meal. The results show that high-protein (PROT) v. high-carbohydrate (CARB) conditions were generated using protein or carbohydrate drinks at the first meal. Energy intake and hunger were recorded. PROT (protein: 53·7 (sd 2·1) percentage of energy (En%); carbohydrate: 6·4 (sd 1·3) En%) and CARB conditions (protein: 11·8 (sd 0·6) En%; carbohydrate: 70·0 (sd 2·4) En%) were achieved during the first meal, while the second meals were not different between the conditions. Hunger, energy intake, and behavioural liking and wanting ratings were decreased after the first meal (P< 0·001). Comparing the first with the second meal, the macronutrient content changed: carbohydrate − 26·9 En% in the CARB condition, protein − 37·8 En% in the PROT condition. After the first meal in the CARB condition, wanting TRS was increased in the hypothalamus. After the first meal in the PROT condition, liking TRS was decreased in the putamen (P< 0·05). The change in energy intake from the first to the second meal was inversely related to the change in liking TRS in the striatum and hypothalamus in the CARB condition and positively related in the PROT condition (P< 0·05). In conclusion, wanting and liking TRS were affected differentially with a change in carbohydrate or protein intake, underscoring subsequent energy intake and shift in macronutrient composition.

Efficacy of Olibra: a 12-week randomized controlled trial and a review of earlier studies

BACKGROUND

Intervention strategies that harness the body's appetite and satiety regulating signals provide a means of countering excessive energy intake.

METHODS

Eighty-two subjects were enrolled (18-60 years, body mass index: 25-40 kg/m(2)) in a randomized, placebo-controlled, double-blind, parallel trial. During a 12-week period, the effects of Olibra™ fat emulsion (2.1 g twice daily) on food intake, appetite, satiety, weight, and body composition were compared with those of a twice daily administered placebo (1.95 g milk fat). On days -7, 0, and 28, Olibra or the placebo added to 200 g of yogurt was served at breakfast and lunch. Food intake, appetite, and satiety were assessed after lunch and dinner. Body weight was measured on days -7, 0, 14, 28, 56, and 84. Body fat, waist circumference, and waist-hip ratio were determined on days 0 and 84. The Eating Inventory was administered at screening and on day 28. Data relating to 71 subjects were analyzed using analysis of covariance.

RESULTS

At 12 weeks, body weight was reduced in the test group (2.17 ± 0.46 kg standard error of the mean, p < .0001) and the control group (1.68 ± 0.42 kg, p < .0001). Waist circumference decreased by 2.93 ± 0.85 cm in the test group (p = .001) and by 1.78 ± 0.74 cm in the control group (p = .02). Differential weight and waist circumference reductions were not significant. Hunger scores (Eating Inventory) decreased more in the test group (p = .0082). Differential group effects were not significant for body fat, waist-hip ratio, food intake, appetite, and satiety.

CONCLUSIONS

At this dose, Olibra did not exert a consistent effect on food intake, appetite regulation, body weight, or body composition.

N-glycan based biomarker distinguishing non-alcoholic steatohepatitis from steatosis independently of fibrosis

BACKGROUND

Non-alcoholic fatty liver disease is a spectrum of disorders ranging from steatosis to non-alcoholic steatohepatitis (NASH). Steatosis of the liver is benign, whereas NASH can progress to cirrhosis or even hepatocellular carcinoma. Currently, a liver biopsy is the only validated method to distinct NASH from steatosis.

AIM

The objective of this study was to identify a biomarker specific for NASH based on the N-glycosylation of serum proteins.

METHODS

N-glycosylation patterns were assessed using DNA sequencer-assisted fluorophore-assisted capillary electrophoresis and compared with histology.

RESULTS

Initially, a glycomarker (log[NGA2F]/[NA2]) was developed based on the results obtained in 51 obese non-alcoholic patients scheduled for bariatric surgery. Multivariate analysis showed that our glycomarker had the lowest P-value of all biomarkers in distinguishing NASH from steatosis (P=0.069). The glycomarker was validated in a cohort of 224 non-alcoholic fatty liver disease patients. In both pilot and validation study, glycomarker score increased in ascending amount of lobular inflammation (single-factor ANOVA, P ≤ 0.001 and P=0.012, respectively). The N-glycan profile of immunoglobulin G in the NASH population confirmed the significantly increased undergalactosylation present in these patients.

CONCLUSION

Our glycomarker specifically recognises liver inflammation in obese individuals which is the main trigger for the development of steatohepatitis and can differentiate between steatosis and NASH.

The Impact of Maternal High-Fat Diet Consumption on Neural Development and Behavior of Offspring

Maternal diet and metabolic state are important factors in determining the environment experienced during perinatal development. Epidemiological studies and evidence from animal models provide evidence that a mother's diet and metabolic condition are important in programming the neural circuitry that regulates behavior, resulting in a persistent impact on the offspring's behavior. Potential mechanisms by which maternal diet and metabolic profile influence the perinatal environment include placental dysfunction and increases in circulating factors such as inflammatory cytokines, nutrients (glucose and fatty acids) and hormones (insulin and leptin). Maternal obesity and high-fat diet (HFD) consumption exposure during development have been observed to increase the risk of developing serious mental health and behavioral disorders including anxiety, depression, attention deficit hyperactivity disorder and autism spectrum disorder. The increased risk of developing these behavioral disorders is postulated to be due to perturbations in the development of neural pathways that regulate behavior, including the serotonergic, dopaminergic and melanocortinergic systems. It is critical to examine the influence that a mother's nutrition and metabolic profile have on the developing offspring considering the current and alarmingly high prevalence of obesity and HFD consumption in pregnant women.

Exercise intervention for management of obesity

Obesity touches the lives of most Americans regardless of age. In adults, accrual of co-morbidities, including frank disability, impacts health in ways that mandate aggressive public health action. In children, the rising prevalence of overweight and obesity raises serious prospective concerns for life as these children enter adulthood. Action is imperative to provide medical interventions and preventive strategies to reduce the threat this condition poses to future generations. Obesity primarily results from an energy regulation imbalance within the body; understanding its origin and effects requires considering both the intake (via eating) and output (via moving) of energy. This article focuses on how exercise and physical activity (i.e., energy output) can influence the primary condition of obesity and its health sequelae. Components, strategies, and expected outcomes of exercise and lifestyle activity are addressed. Successful long-term participation in daily movement requires matching exercise regimens and physical activity outlets to individual preferences and environmental conditions. Activity habits of Americans must change at home and in the workplace, schools and the community to positively influence health. Although the goals of Healthy People 2010 to reduce sedentary behavior have not been met, success of other public health interventions (e.g., immunizations, use of bicycle helmets) suggests that social change to alter activity habits can be achieved. Failure to reach our public health goals should serve as a catalyst for broad-based action to help children, adolescents, and adults attain and maintain behaviors that reduce the risk of obesity and its health insults.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Vitamin D and the vascular sensitivity to angiotensin II in obese Caucasians with hypertension

Obesity and vitamin D deficiency have both been linked to augmented activity of the tissue renin-angiotensin system (RAS). We investigated whether obesity status influenced the relationship between 25-hydroxyvitamin D (25(OH)D) and vascular RAS activity. The levels of 25(OH)D were measured in hypertensive obese (n=39) and non-obese (n=58) Caucasian individuals. RAS activity was assessed by plasma renin activity, and evaluation of the vascular sensitivity to angiotensin II (AngII) using the mean arterial pressure (MAP) response to an infusion of AngII. Among obese subjects, 25(OH)D was an independent positive predictor of the MAP response to AngII (β=0.70, r=0.41, P<0.01); lower 25(OH)D concentrations were associated with a blunted MAP response to AngII. In contrast, 25(OH)D did not significantly predict the vascular sensitivity to AngII in non-obese subjects (β=0.10, r=0.07, P=0.62). A multivariable-adjusted interaction model confirmed that the positive relationship between 25(OH)D and the vascular sensitivity to AngII strengthened with obesity (P-interaction=0.03). These findings demonstrate a positive association between 25(OH)D and the vascular sensitivity to AngII in obese hypertensives, and further suggest that vascular RAS activity may progressively increase when 25(OH)D deficiency occurs in obesity. Future studies to evaluate the effect of vitamin D supplementation on vascular RAS activity in obesity are needed.

Obesity is associated with impaired immune response to influenza vaccination in humans

Background:

Obesity is an independent risk factor for morbidity and mortality from pandemic influenza H1N1. Influenza is a significant public health threat, killing an estimated 250 000–500 000 people worldwide each year. More than one in ten of the world's adult population is obese and more than two-thirds of the US adult population is overweight or obese. No studies have compared humoral or cellular immune responses to influenza vaccination in healthy weight, overweight and obese populations despite clear public health importance.

Objective:

The study employed a convenience sample to determine the antibody response to the 2009–2010 inactivated trivalent influenza vaccine (TIV) in healthy weight, overweight and obese participants at 1 and 12 months post vaccination. In addition, activation of CD8⁺ T cells and expression of interferon-γ and granzyme B were measured in influenza-stimulated peripheral blood mononuclear cell (PBMC) cultures.

Results:

Body mass index (BMI) correlated positively with higher initial fold increase in IgG antibodies detected by enzyme-linked immunosorbent assay to TIV, confirmed by HAI antibody in a subset study. However, 12 months post vaccination, higher BMI was associated with a greater decline in influenza antibody titers. PBMCs challenged ex vivo with vaccine strain virus, demonstrated that obese individuals had decreased CD8⁺ T-cell activation and decreased expression of functional proteins compared with healthy weight individuals.

Conclusion:

These results suggest obesity may impair the ability to mount a protective immune response to influenza virus.

Castration-induced changes in mouse epididymal white adipose tissue

We analyzed the effects of castration on epididymal white adipose tissue (WAT) in C57BL/6J mice which were fed a regular or high-fat diet. Fourteen days following surgical castration profound effects on WAT tissue such as reductions in WAT wet weight and WAT/body weight ratio, induction of lipolysis and morphologic changes characterized by smaller adipocytes, and increased stromal cell compartment were documented in both dietary groups. Castrated animals had decreased serum leptin levels independent of diet but diet-dependent decreases in serum adiponectin and resistin. The castrated high-fat group had dramatically lower serum triglyceride levels. Immunohistochemical analysis revealed higher staining for smooth muscle actin, macrophage marker Mac-3, and Cxcl5 in the castrated than in the control mice in both dietary groups. We also detected increased fatty-acid synthase expression in the stromal compartment of WAT in the regular-diet group. Castration also reduces the expression of androgen receptor in WAT in the regular-diet group. We conclude that castration reduces tissue mass and affects biologic function of WAT in mice.

Biology's response to dieting: the impetus for weight regain

Dieting is the most common approach to losing weight for the majority of obese and overweight individuals. Restricting intake leads to weight loss in the short term, but, by itself, dieting has a relatively poor success rate for long-term weight reduction. Most obese people eventually regain the weight they have worked so hard to lose. Weight regain has emerged as one of the most significant obstacles for obesity therapeutics, undoubtedly perpetuating the epidemic of excess weight that now affects more than 60% of U.S. adults. In this review, we summarize the evidence of biology's role in the problem of weight regain. Biology's impact is first placed in context with other pressures known to affect body weight. Then, the biological adaptations to an energy-restricted, low-fat diet that are known to occur in the overweight and obese are reviewed, and an integrative picture of energy homeostasis after long-term weight reduction and during weight regain is presented. Finally, a novel model is proposed to explain the persistence of the "energy depletion" signal during the dynamic metabolic state of weight regain, when traditional adiposity signals no longer reflect stored energy in the periphery. The preponderance of evidence would suggest that the biological response to weight loss involves comprehensive, persistent, and redundant adaptations in energy homeostasis and that these adaptations underlie the high recidivism rate in obesity therapeutics. To be successful in the long term, our strategies for preventing weight regain may need to be just as comprehensive, persistent, and redundant, as the biological adaptations they are attempting to counter.

Differences between liking and wanting signals in the human brain and relations with cognitive dietary restraint and body mass index

BACKGROUND

Eating behavior is determined, to a significant extent, by the rewarding value of food (ie, liking and wanting).

OBJECTIVE

We determined brain regions involved in liking and wanting and related brain signaling to body mass index (BMI; in kg/m(2)) and dietary restraint.

DESIGN

Fifteen normal-weight female subjects [mean ± SEM age: 21.5 ± 0.4 y; BMI: 22.2 ± 0.2] completed a food-choice paradigm by using visually displayed food items during functional magnetic resonance imaging scans. Two scans were made as follows: one scan was made in a fasted condition, and one scan was made in a satiated condition. The paradigm discriminated between liking and wanting, and subjects were offered items rated highly for wanting immediately after each scan. Imaging contrasts for high and low liking and wanting were made, and data for regions of interest were extracted. Activation related to liking and wanting, respectively, was determined. Outcomes were correlated to cognitive dietary restraint and BMI.

RESULTS

Dietary restraint predicted liking task-related signaling (TRS) in the amygdala, striatum, thalamus, and cingulate cortex (r = -0.5 ± 0.03, P < 0.00001). In the nucleus accumbens, the premeal liking and wanting TRS and premeal to postmeal liking TRS changes correlated positively with dietary restraint [bilateral average r = 0.6 ± 0.02, P < 0.04 (Bonferroni corrected)]. BMI and hunger predicted wanting TRS in the hypothalamus and striatum (P < 0.05). Postmeal liking TRS in the striatum, anterior insula, and cingulate cortex and wanting TRS in the striatum predicted the energy intake (liking: r = -0.3 ± 0.05, P < 0.0001; wanting: r = -0.3 ± 0.03, P < 0.00001).

CONCLUSIONS

Successful dietary restraint was supported by liking TRS from premeal to postmeal in the nucleus accumbens. Reward-related signaling was inversely related to BMI and energy intake, indicating reward deficiency.