Body image changes associated with participation in an intensive lifestyle weight loss intervention

The primary aim of this study was to test for changes in body image in men and women enrolled in the Look AHEAD trial. Look AHEAD (Action for Health in Diabetes) is a multicenter, randomized controlled trial designed to test whether intentional weight loss reduces cardiovascular morbidity and mortality in overweight individuals with type 2 diabetes. Participants included 157 adults at one site (Pennington Biomedical Research Center (PBRC), Baton Rouge, LA) of the Look AHEAD study. At baseline, the mean BMI of the female participants was 36.4, and the mean BMI for males was 33.5. Following baseline assessment, participants were randomly assigned to the intensive lifestyle intervention (ILI, n = 81) or diabetes support and education (DSE, n = 76). The body morph assessment version 2.0 (BMA 2.0) was used to assess estimates of perceived current body size, ideal body size, acceptable body size, and body image dissatisfaction at baseline and 1 year. Over the 1 year, participants in the ILI group had significantly greater reductions in weight (10.1% for men and 8.9% for women) than those in the DSE group (+ 0.8% for men and -0.2%, for women). Perceived current body size was reduced significantly more in both men and women in the ILI group, relative to DSE. There were also significantly greater reductions in body image dissatisfaction in the ILI group, relative to the DSE group for men and women. The results of this study indicate that body image dissatisfaction improved following participation in an intensive behavioral weight loss program.

Ethnic-specific BMI and waist circumference thresholds

BMI and waist circumference (WC) are used to identify individuals with elevated obesity-related health risks. The current thresholds were derived largely in populations of European origin. This study determined optimal BMI and WC thresholds for the identification of cardiometabolic risk among white and African-American (AA) adults. The sample included 2096 white women, 1789 AA women, 1948 white men, and 643 AA men aged 18-64 years. Elevated cardiometabolic risk was defined as ≥2 risk factors (blood pressure ≥ 130/85 mm Hg; glucose ≥100 mg/dl; triglycerides ≥150 mg/dl; high-density lipoprotein-cholesterol <40 mg/dl (men) or <50 mg/dl (women)). Receiver Operating Characteristic (ROC) curves were used to identify optimal BMI and WC thresholds in each sex-by-ethnicity group. The optimal BMI thresholds were 30 kg/m2 in white women, 32.9 kg/m2 in AA women, 29.1 kg/m2 white men, and 30.4 kg/m2 in AA men, whereas optimal WC thresholds were 91.9 cm in white women, 96.8 cm in AA women, 99.4 in white men, and 99.1 cm in AA men. The sensitivities at the optimal thresholds ranged from 63.5 to 68.5% for BMI and 68.4 to 71.0% for WC and the specificities ranged from 64.2 to 68.8% for BMI and from 68.5 to 71.0% for WC, respectively. In general, the optimal BMI and WC thresholds approximated currently used thresholds in men and in white women. There are no apparent ethnic differences in men; however, in AA women the optimal BMI and WC values are ~3 kg/m2 and 5 cm higher than in white women.

Trunk versus extremity adiposity and cardiometabolic risk factors in white and African American adults

OBJECTIVE

To determine contributions of trunk and extremity adiposity to cardiometabolic risk factors (blood pressure, fasting blood glucose, HDL cholesterol, and triglycerides) among white and African American adults.

RESEARCH DESIGN AND METHODS

The sample consisted of 1,129 white women, 779 African American women, 1,012 white men, and 300 African American men.

RESULTS

Higher trunk adiposity was significantly associated with an increased risk of having two or more cardiometabolic risk factors among African American and white men and women. After adjustment for trunk and arm adiposity, higher leg adiposity was significantly associated with a decreased risk of having two or more cardiometabolic risk factors among white men and women and African American women.

CONCLUSIONS

In contrast with adverse risk with high trunk adiposity, high leg adiposity is associated with a decreased risk of having two or more cardiometabolic risk factors in both African American and white adults.

Pioglitazone for diabetes prevention in impaired glucose tolerance

BACKGROUND

Impaired glucose tolerance is associated with increased rates of cardiovascular disease and conversion to type 2 diabetes mellitus. Interventions that may prevent or delay such occurrences are of great clinical importance.

METHODS

We conducted a randomized, double-blind, placebo-controlled study to examine whether pioglitazone can reduce the risk of type 2 diabetes mellitus in adults with impaired glucose tolerance. A total of 602 patients were randomly assigned to receive pioglitazone or placebo. The median follow-up period was 2.4 years. Fasting glucose was measured quarterly, and oral glucose tolerance tests were performed annually. Conversion to diabetes was confirmed on the basis of the results of repeat testing.

RESULTS

Annual incidence rates for type 2 diabetes mellitus were 2.1% in the pioglitazone group and 7.6% in the placebo group, and the hazard ratio for conversion to diabetes in the pioglitazone group was 0.28 (95% confidence interval, 0.16 to 0.49; P<0.001). Conversion to normal glucose tolerance occurred in 48% of the patients in the pioglitazone group and 28% of those in the placebo group (P<0.001). Treatment with pioglitazone as compared with placebo was associated with significantly reduced levels of fasting glucose (a decrease of 11.7 mg per deciliter vs. 8.1 mg per deciliter [0.7 mmol per liter vs. 0.5 mmol per liter], P<0.001), 2-hour glucose (a decrease of 30.5 mg per deciliter vs. 15.6 mg per deciliter [1.6 mmol per liter vs. 0.9 mmol per liter], P<0.001), and HbA(1c) (a decrease of 0.04 percentage points vs. an increase of 0.20 percentage points, P<0.001). Pioglitazone therapy was also associated with a decrease in diastolic blood pressure (by 2.0 mm Hg vs. 0.0 mm Hg, P=0.03), a reduced rate of carotid intima-media thickening (31.5%, P=0.047), and a greater increase in the level of high-density lipoprotein cholesterol (by 7.35 mg per deciliter vs. 4.5 mg per deciliter [0.4 mmol per liter vs. 0.3 mmol per liter], P=0.008). Weight gain was greater with pioglitazone than with placebo (3.9 kg vs. 0.77 kg, P<0.001), and edema was more frequent (12.9% vs. 6.4%, P=0.007).

CONCLUSIONS

As compared with placebo, pioglitazone reduced the risk of conversion of impaired glucose tolerance to type 2 diabetes mellitus by 72% but was associated with significant weight gain and edema. (Funded by Takeda Pharmaceuticals and others; ClinicalTrials.gov number, NCT00220961.).

The relationship of waist circumference and BMI to visceral, subcutaneous, and total body fat: sex and race differences

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.

Olfactory bulbectomy impairs the feeding response to 2-deoxy-D-glucose in rats

An early study reported that, unlike sham-operated rats, rats made anosmic by olfactory bulbectomy (OBX) failed to compensate for the dilution of their diet with nonnutritive bulk by increasing their food intake. In the present study, the effects of a glucoprivic challenge, intraperitoneal-administered 350 mg/kg 2-deoxy-D-glucose (2-DG), on food intake were measured in OBX and sham-operated female rats. Sham-operated rats significantly increased their food intake, but in two separate experiments OBX rats displayed no increase in food intake during the first 2 h following administration. Blood glucose levels were nearly identical in both groups. Body weights and daily food intakes of OBX rats did not differ from the sham-operated controls throughout the studies. Bulbectomized rats also displayed a normal drinking response after an intraperitoneal injection of 1M hypertonic saline. Hypothalamic nuclei and the neural pathways mediating taste have been implicated in the feeding response to 2-DG. The present results suggest that olfactory input and olfactory neural pathways also mediate, at least in part, the feeding response to a glucoprivic challenge induced by intraperitoneal injection of 2-DG.

Reversal of small, dense LDL subclass phenotype by weight loss is associated with impaired fat oxidation

Adiposity is more prevalent among individuals with a predominance of small, dense low-density lipoprotein (LDL) (pattern B) particles than among those with larger LDL (pattern A). We tested for differences in resting energy expenditure (REE) and respiratory quotient (RQ) in overweight men with pattern A (n = 36) or pattern B (n = 60). Men consumed a standardized isoenergetic diet for 3 weeks after which a ~9 kg weight loss was induced by caloric deficit for 9 weeks, followed by 4 weeks of weight stabilization. REE and RQ were measured by indirect calorimetry before and after weight loss. Results were analyzed separately in pattern B men who converted to pattern A (B→A; n = 35) and those who did not (B→B; n = 25). At baseline, B→B men had higher trunk fat, triacylglycerol (TG) and insulin concentrations, homeostasis model assessment of insulin resistance (HOMA(IR)), and smaller LDL particles compared to B→A men and baseline pattern A men who remained pattern A (A→A; n = 35). REE normalized to fat-free mass did not change after weight loss. RQ decreased in A→A men, increased in B→A men, and did not change significantly in B→B men after weight loss. Calculated fat oxidation rates paralleled the RQ results. Baseline plasma TG concentrations were positively correlated with RQ and inversely correlated with the magnitude of weight loss achieved for a given prescribed energy reduction in the entire study population. Pattern B men who converted to pattern A with weight loss may have an underlying impairment in fat oxidation that predisposes to both dyslipidemia and an impaired ability to achieve weight loss by energy restriction.

Sugar-sweetened beverages and risk of metabolic syndrome and type 2 diabetes: a meta-analysis

OBJECTIVE

Consumption of sugar-sweetened beverages (SSBs), which include soft drinks, fruit drinks, iced tea, and energy and vitamin water drinks has risen across the globe. Regular consumption of SSBs has been associated with weight gain and risk of overweight and obesity, but the role of SSBs in the development of related chronic metabolic diseases, such as metabolic syndrome and type 2 diabetes, has not been quantitatively reviewed.

RESEARCH DESIGN AND METHODS

We searched the MEDLINE database up to May 2010 for prospective cohort studies of SSB intake and risk of metabolic syndrome and type 2 diabetes. We identified 11 studies (three for metabolic syndrome and eight for type 2 diabetes) for inclusion in a random-effects meta-analysis comparing SSB intake in the highest to lowest quantiles in relation to risk of metabolic syndrome and type 2 diabetes.

RESULTS

Based on data from these studies, including 310,819 participants and 15,043 cases of type 2 diabetes, individuals in the highest quantile of SSB intake (most often 1-2 servings/day) had a 26% greater risk of developing type 2 diabetes than those in the lowest quantile (none or <1 serving/month) (relative risk [RR] 1.26 [95% CI 1.12-1.41]). Among studies evaluating metabolic syndrome, including 19,431 participants and 5,803 cases, the pooled RR was 1.20 [1.02-1.42].

CONCLUSIONS

In addition to weight gain, higher consumption of SSBs is associated with development of metabolic syndrome and type 2 diabetes. These data provide empirical evidence that intake of SSBs should be limited to reduce obesity-related risk of chronic metabolic diseases.

Pioglitazone, but not metformin, reduces liver fat in Type-2 diabetes mellitus independent of weight changes

BACKGROUND

Pioglitazone (Pio) treatment induces weight gain in Type 2 diabetes mellitus (T2DM), which could worsen hepatic lipid accumulation, and alter adiponectin and high-sensitivity C-reactive protein (hs-CRP).

OBJECTIVE

To compare changes in hepatic lipid, serum adiponectin and hs-CRP in diabetics treated with Pio (with and without weight gain) against metformin (Met) treatment, which produces weight loss.

DESIGN

Fifty-one men and women with T2DM, naive to thiazolidinediones, entered a 16-week, open-label, parallel arm study, where participants were randomized to one of three groups: (1) Pio plus the American Diabetes Association diet (Pio+ADA); (2) Pio plus a portion control weight loss diet (Pio+PC), or (3) metformin plus ADA diet (Met+ADA).

METHODS

Hepatic lipid was assessed with abdominal computed tomography (CT) and the serum adiponectin and hs-CRP by enzyme-linked immunosorbent assay at baseline and study end.

RESULTS

Forty-eight subjects completed the study. The Pio+ADA group gained (mean+/-S.E.M.) 2.15+/-1.09 kg, while Pio+PC and Met+ADA group lost -2.59+/-1.25 and -3.21+/-0.7 kg, respectively. Pio-treated groups (Pio+ADA and Pio+PC) significantly decreased hepatic fat as indicated by increased liver density on CT scan [10.1+/-2.4: 11.4+/-1.0 Hounsfield units (HU)], compared with Met+ADA group (-2.4+/-3.1 HU). The Pio groups demonstrated significantly increased serum adiponectin, (8.6+/-1.5; 7.4+/-1.6 microg/ml) independent of weight change, compared to Met+ADA (-0.14+/-0.6 microgm/ml) group which lost weight. Serum hs-CRP decreased in groups showing weight loss (Pio+PC, -3.1+/-1.7 mg/l; Met+ADA, -1.5+/-1.2 mg/l) compared to Pio+ADA (1.8+/-3.0 mg/l) group that gained weight.

CONCLUSIONS

Pio treatment in T2DM significantly reduced hepatic lipid and increased adiponectin independent of weight change, while decreasing hs-CRP with weight loss.

Fructose: pure, white, and deadly? Fructose, by any other name, is a health hazard

The worldwide consumption of sucrose, and thus fructose, has risen logarithmically since 1800. Many concerns about the health hazards of calorie-sweetened beverages, including soft drinks and fruit drinks and the fructose they provide, have been voiced over the past 10 years. These concerns are related to higher energy intake, risk of obesity, risk of diabetes, risk of cardiovascular disease, risk of gout in men, and risk of metabolic syndrome. Fructose appears to be responsible for most of the metabolic risks, including high production of lipids, increased thermogenesis, and higher blood pressure associated with sugar or high fructose corn syrup. Some claim that sugar is natural, but natural does not assure safety.

Combination drugs for treating obesity

Although obesity is a chronic disease like hypertension and diabetes, obesity is not treated with drug combinations as are other chronic diseases. This is because orlistat and sibutramine, the two drugs approved for long-term treatment of obesity, do not result in additive weight loss when combined. This article discusses the history of combination drug therapy for treating obesity, the lessons learned from that experience, and describes the drug combinations now in development. One combination of two standardized dietary herbal supplements that result in clinically significant weight loss is also described. Obesity is poised to enter the era of combination drug therapy, as is now the routine in the treatment of other chronic diseases like hypertension and diabetes. The advent of combination drug therapy for obesity treatment offers hope for increasing the efficacy of obesity pharmacotherapy.

Effect of pioglitazone on energy intake and ghrelin in diabetic patients

OBJECTIVE

To measure ghrelin and energy intake in the laboratory after pioglitazone treatment.

RESEARCH DESIGN AND METHODS

This was a parallel, three-arm study with 51 obese diabetic subjects randomized to either 1) pioglitazone plus a portion-controlled diet (Pio+PC), 2) pioglitazone plus American Diabetes Association (ADA) dietary advice (Pio+ADA), or 3) metformin plus ADA advice (Met+ADA). Energy intake and the suppressive response of a meal on ghrelin were measured at weeks 0 and 16. Mixed models tested if changes from week 0 to 16 differed by group.

RESULTS

The Pio+ADA group had a significantly larger increase (P < 0.05) in energy intake ([adjusted means +/- SE] 207 +/- 53 kcal) compared with the Pio+PC (50 +/- 46 kcal) and Met+ADA (52 +/- 49 kcal) groups. Change in restraint and disinhibition (variables associated with eating behavior) mediated weight change. Ghrelin suppression increased in the Pio+ADA group, which gained weight.

CONCLUSIONS

A portion-controlled diet attenuated the increase in energy intake after pioglitazone. Ghrelin responded to weight change not pioglitazone exposure.

Effect of a 3-day high-fat feeding period on carbohydrate balance and ad libitum energy intake in humans

OBJECTIVE

A reduction in glycogen after the switch to an isoenergetic high-fat diet (HFD) might promote a compensatory increase in food intake to reestablish carbohydrate balance. We assessed the effect of an isoenergetic switch from a 49%-carbohydrate to 50%-fat diet on nutrient balance and ad libitum food intake. We hypothesized that carbohydrate balance would be inversely related to ad libitum energy intake.

METHODS

In 47 men and 11 women (22.6+/-0.4 years; 26.1+/-0.5 kg m(-2)), fuel balance was measured in a respiration chamber over 4 days. During the first day, an isoenergetic, high-carbohydrate diet was provided followed by a 3-day isoenergetic, HFD. At the end of this period and after 16 h of fasting, three options of foods (cookies, fruit salad and turkey sandwich) were offered ad libitum for 4 h. The relationships between post-chamber ad libitum intake and macronutrient oxidation and balance measured day-to-day and over the 4-day respiration chamber stay were studied.

RESULTS

After switching to a HFD, 24-h respiratory quotient decreased from 0.87+/-0.02 to 0.83+/-0.02 (P<0.0001) resulting in a 4-day cumulative carbohydrate, fat and protein balances of -183+/-368, 342+/-480 and 65+/-267 kcal, respectively. Cumulative energy balance (224+/-362 kcal per 4 days) did not influence ad libitum energy intake. However, we detected that 4-day carbohydrate balance was a positive and independent predictor of post-chamber ad libitum energy intake (R (2)=0.10; P=0.01), whereas no significant influence of fat and protein balances was found.

CONCLUSION

In response to an isoenergetic change from a high-carbohydrate to HFD, higher carbohydrate balance related to increased energy intake.

Determinants of glucose tolerance in impaired glucose tolerance at baseline in the Actos Now for Prevention of Diabetes (ACT NOW) study

AIMS/HYPOTHESIS

The aim of the study was to examine the determinants of oral glucose tolerance in 602 persons with impaired glucose tolerance (IGT) who participated in the Actos Now for Prevention of Diabetes (ACT NOW) study.

METHODS

In addition to the 602 IGT participants, 115 persons with normal glucose tolerance (NGT) and 50 with impaired fasting glucose (IFG) were identified during screening and included in this analysis. Insulin secretion and insulin sensitivity indices were derived from plasma glucose and insulin during an OGTT. The acute insulin response (AIR) (0-10 min) and insulin sensitivity (S(I)) were measured with the frequently sampled intravenous glucose tolerance test (FSIVGTT) in a subset of participants.

RESULTS

At baseline, fasting plasma glucose, 2 h postprandial glucose (OGTT) and HbA(1c) were 5.8 +/- 0.02 mmol/l, 10.5 +/- 0.05 mmol/l and 5.5 +/- 0.04%, respectively, in participants with IGT. Participants with IGT were characterised by defects in early (DeltaI (0-30)/DeltaG (0-30) x Matsuda index, where DeltaI is change in insulin in the first 30 min and DeltaG is change in glucose in the first 30 min) and total (DeltaI(0-120)/DeltaG(0-120) x Matsuda index) insulin secretion and in insulin sensitivity (Matsuda index and S(I)). Participants with IGT in whom 2 h plasma glucose was 7.8-8.3 mmol/l had a 63% decrease in the insulin secretion/insulin resistance (disposition) index vs participants with NGT and this defect worsened progressively as 2 h plasma glucose rose to 8.9-9.94 mmol/l (by 73%) and 10.0-11.05 mmol/l (by 80%). The Matsuda insulin sensitivity index was reduced by 40% in IGT compared with NGT (p < 0.005). In multivariate analysis, beta cell function was the primary determinant of glucose AUC during OGTT, explaining 62% of the variance.

CONCLUSION

Our results strongly suggest that progressive beta cell failure is the main determinant of progression of NGT to IGT.

Nonsurgical weight loss for extreme obesity in primary care settings: results of the Louisiana Obese Subjects Study

BACKGROUND

Effective primary care practice (PCP) treatments are needed for extreme obesity. The Louisiana Obese Subjects Study (LOSS) tested whether, with brief training, PCPs could effectively implement weight loss for individuals with a body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) of 40 to 60.

METHODS

The LOSS, a 2-year (July 5, 2005, through January 30, 2008) randomized, controlled, "pragmatic clinical trial" trained 7 PCPs and 1 research clinic in obesity management. Primary outcome measure was year-2 percentage change from baseline weight. Volunteers (597) were screened and randomized to intensive medical intervention (IMI) (n = 200) or usual care condition (UCC) (n = 190). The UCC group had instruction in an Internet weight management program. The IMI group recommendations included a 900-kcal liquid diet for 12 weeks or less, group behavioral counseling, structured diet, and choice of pharmacotherapy (sibutramine hydrochloride, orlistat, or diethylpropion hydrochloride) during months 3 to 7 and continued use of medications and maintenance strategies for months 8 to 24.

RESULTS

The mean age of participants was 47 years; 83% were women, and 75% were white. Retention rates were 51% for the IMI group and 46% for the UCC group (P = .30). After 2 years, the results were as follows: (1) among 390 randomized participants, 31% in the IMI group achieved a 5% or more weight loss and 7% achieved a 20% weight loss or more, compared with 9% and 1% of those in the UCC group. (2) The mean +/- SEM baseline observation carried forward analysis showed a weight loss of -4.9% +/- 0.8% in IMI and -0.2 +/- 0.3% in UCC. (3) Last observation carried forward analysis showed a weight loss of -8.3% +/- 0.79% for IMI, whereas UCC was -0.0% +/- 0.4%. (4) A total of 101 IMI completers lost -9.7% +/- 1.3% (-12.7 +/- 1.7 kg), whereas 89 UCC completers lost -0.4% +/- 0.7% (-0.5 +/- 0.9 kg); (P < .001 for all group differences). Many metabolic parameters improved.

CONCLUSION

Primary care practices can initiate effective medical management for extreme obesity; future efforts must target improving retention and weight loss maintenance.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00115063.

Soft drink consumption and obesity: it is all about fructose

PURPOSE OF REVIEW

The purpose of the review is to suggest that fructose, a component of both sucrose (common sugar) and high fructose corn syrup, should be of concern to both healthcare providers and the public.

RECENT FINDINGS

Consumption of sugar-sweetened beverages has increased steadily over the past century and with this increase has come more and more reports associating their use with the risk of overweight, diabetes and cardiometabolic disease. In a meta-analysis of the relationship between soft drink consumption and cardiometabolic risk, there was a 24% overall increased risk comparing the top and bottom quantiles of consumption. Several factors might account for this increased risk, including increased carbohydrate load and increased amounts of dietary fructose. Fructose acutely increases thermogenesis, triglycerides and lipogenesis as well as blood pressure, but has a smaller effect on leptin and insulin release than comparable amounts of glucose. In controlled feeding studies, changes in body weight, fat storage and triglycerides are observed as well as an increase in inflammatory markers.

SUMMARY

The present review concludes on the basis of the data assembled here that in the amounts currently consumed, fructose is hazardous to the cardiometabolic health of many children, adolescents and adults.

Preference for a high fat diet, but not hyperphagia following activation of mu opioid receptors is blocked in AgRP knockout mice

Activation of mu opioid receptors (MOR) makes animals hyperphagic and selectively increases their preference for a high fat diet independent of their dietary preference. The orexigenic peptide Agouti Related Peptide (AgRP) also produces hyperphagia and increased the preference for a high fat diet. In this paper, we tested the hypothesis that the effect of MOR on feeding behavior will be attenuated in the absence of the orexigenic peptide AgRP. Immunohistochemical studies demonstrated that MOR are co-localized on AgRP neurons located in the arcuate nucleus. This finding is consistent with a role of MOR in mediating the release of AgRP. Our data also demonstrated that the wild-type (FVB) animals preferred a diet high in fat whereas the AgRP knockout (AgRP KO) mice did not. mRNA expression of MOR in the hypothalamus was not significantly different between AgRP KO mice and their wild-type control. In a dose-response experiment, the low dose (0.025 microg) of a MOR agonist, DAMGO, increased cumulative food intake in wild-type and AgRP KO mice. The low and middle (0.25 microg) dose of DAMGO significantly increased the amount of high fat diet eaten by the wild-type animals, but did not significantly change the amount of high fat diet eaten by the AgRP KO mice. The highest dose of DAMGO (2.5 microg) reduced food intake in the control and AgRP KO mice, probably due to somnolence. These data demonstrate that the increased preference for a high fat diet after stimulation of MOR is attenuated in the absence of AgRP, but the increase in food intake (i.e. hyperphagia) is not.

Racial differences in abdominal depot-specific adiposity in white and African American adults

BACKGROUND

There is increasing interest in understanding racial differences in adiposity in specific body depots as a way to explain differential health risks associated with obesity.

OBJECTIVE

Our aim was to examine the differences in abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) between white and African American adults.

DESIGN

The sample included 1967 adults aged 18-84 y, including 790 white women, 435 African American women, 606 white men, and 136 African American men. Total body fat was measured by using dual-energy X-ray absorptiometry, whereas abdominal VAT and SAT cross-sectional areas (L4-L5 level) were measured by using computed tomography. Sex-specific differences in SAT and VAT between racial groups were analyzed by the use of general linear models, which controlled for age and total body fat. Additional models tested for racial differences in VAT and SAT and controlled for age, total body fat, smoking, and menopausal status. Statistical significance was accepted at P < 0.05.

RESULTS

Abdominal VAT was significantly higher in white than in African American men and women, even after adjustment for covariates. White women had significantly lower SAT than did African American women, both before and after adjustment for covariates. White men had significantly higher SAT than did African American men, but after adjustment for covariates, their SAT was lower than that of African American men.

CONCLUSIONS

Abdominal visceral adiposity is significantly greater in white men and women. After adjustment for covariates, white men and women had significantly lower SAT than did African American men and women. The results of this study highlight the heterogeneity of human body fat distribution across racial groups.This trial was registered at clinicaltrials.gov as NCT00959270.

Overweight and obesity: the pathogenesis of cardiometabolic risk

Obesity, particularly abdominal adiposity, is increasingly recognized as a cause of elevated cardiometabolic risk--the risk of developing type 2 diabetes mellitus (DM) and cardiovascular disease (CVD). The predominate mechanisms appear to involve the promotion of insulin resistance, driven largely by excess free fatty acids secreted by an expanded adipose tissue mass, and the development of an inflammatory milieu due to increased secretion of inflammatory cytokines and adipokines from adipose tissue. Key proinflammatory cytokines secreted by adipocytes include tumor necrosis factor-alpha, interleukin-6, leptin, resistin, and plasminogen activator inhibitor-1. All have been variously associated with hyperinsulemia, hyperglycemia, insulin resistance, diabetes, and endothelial dysfunction, as well as plaque development, progression, and rupture. Adiponectin, another important adipocyte, has protective cardiometabolic actions; however, adiponectin levels decline with increasing obesity. Understanding the role of obesity in the pathogenesis of cardiometabolic risk is crucial for the development of treatment strategies that will provide maximum benefit for patients with, or at risk for, type 2 DM and CVD.

Adipose tissue collagen VI in obesity

OBJECTIVES

Basic science studies show that the extracellular matrix of adipose tissue, mainly represented by collagen VI, is dysfunctional in obesity and contributes to the development of the metabolic syndrome. We hypothesized in humans that increased collagen VI alpha3-subunit (COL6A3) mRNA is associated with adipose tissue macrophage chemotaxis and inflammation and that weight gain is accompanied by changes in the expression of COL6A3.

RESEARCH DESIGN AND METHODS

Adipose tissue biopsies were obtained from a cross-sectional study (n = 109), an overfeeding study (n = 9), and a pioglitazone treatment study (n = 14). Adipose tissue gene expression was measured by quantitative RT-PCR, immunohistochemistry, and adipocyte sizing by fixation with osmium and Coulter counting. Body composition was measured by dual-energy x-ray absorptiometry and visceral adipose tissue by computed tomography. Patients with high or low COL6A3 mRNA were compared by one-way ANOVA.

RESULTS

In humans, immunohistochemistry revealed that COL6 is present in adipose tissue extracellular matrix. COL6A3 mRNA is correlated with body mass index (r = 0.60, P < 0.0001) and fat mass (r = 0.41, P < 0.0001). COL6A3 expression was similar in obese vs. type 2 diabetes patients. Obese subjects with high COL6A3 mRNA had greater visceral adipose tissue mass (P < 0.05), lower size of small and medium adipocytes (P < 0.05), more CD68+ and CD163/MAC2+ macrophages, and increased macrophage inflammatory protein-1alpha and macrophage chemoattractant protein-1alpha mRNA (P < 0.05). Eight weeks of overfeeding increased body weight and COL6A3 mRNA (P < 0.05). Pioglitazone decreased COL6A3 mRNA, and the change was inversely proportional to baseline COL6A3 mRNA (r = -0.95, P < 0.0001).

CONCLUSION

These results are consistent with basic science data, suggesting that COL6A3 might contribute to adipose tissue inflammation.

Adherence is a multi-dimensional construct in the POUNDS LOST trial

Research on the conceptualization of adherence to treatment has not addressed a key question: Is adherence best defined as being a uni-dimensional or multi-dimensional behavioral construct? The primary aim of this study was to test which of these conceptual models best described adherence to a weight management program. This ancillary study was conducted as a part of the POUNDS LOST trial that tested the efficacy of four dietary macronutrient compositions for promoting weight loss. A sample of 811 overweight/obese adults was recruited across two clinical sites, and each participant was randomly assigned to one of four macronutrient prescriptions: (1) Low fat (20% of energy), average protein (15% of energy); (2) High fat (40%), average protein (15%); (3) Low fat (20%), high protein (25%); (4) High fat (40%), high protein (25%). Throughout the first 6 months of the study, a computer tracking system collected data on eight indicators of adherence. Computer tracking data from the initial 6 months of the intervention were analyzed using exploratory and confirmatory analyses. Two factors (accounting for 66% of the variance) were identified and confirmed: (1) behavioral adherence and (2) dietary adherence. Behavioral adherence did not differ across the four interventions, but prescription of a high fat diet (vs. a low fat diet) was found to be associated with higher levels of dietary adherence. The findings of this study indicated that adherence to a weight management program was best conceptualized as being multi-dimensional, with two dimensions: behavioral and dietary adherence.

Alcohol consumption and diabetes risk in the Diabetes Prevention Program

BACKGROUND

Moderate alcohol consumption is associated with a decreased risk of type 2 diabetes in the general population, but little is known about the effects in individuals at high risk of diabetes.

OBJECTIVES

The objectives were to determine associations between alcohol consumption and diabetes risk factors and whether alcohol consumption was a predictor of incident diabetes in individuals enrolled in the Diabetes Prevention Program (DPP).

DESIGN

DPP participants (n = 3175) had impaired glucose tolerance (2-h glucose: 7.8-11.1 mmol/L), elevated fasting glucose (5.3-7.0 mmol/L), and a body mass index (in kg/m(2)) > or =24. Participants were randomly assigned to placebo, metformin, or lifestyle modification and were followed for a mean of 3.2 y. Alcohol intake was assessed at baseline and year 1 by using a semiquantitative food-frequency questionnaire. Diabetes was diagnosed by annual oral-glucose-tolerance testing and semiannual fasting plasma glucose measurement.

RESULTS

Participants who reported higher alcohol consumption tended to be male, older, white, and less obese and to have a higher calorie intake and a higher HDL-cholesterol concentration. Higher alcohol consumption was associated with lower insulin secretion at any level of insulin sensitivity. We found lower incidence rates of diabetes with higher alcohol consumption in the metformin (P < 0.01 for trend) and lifestyle modification (P = 0.02 for trend) groups, which remained significant after adjustment for multiple baseline covariates. No similar association was observed in the placebo group.

CONCLUSIONS

Despite overall low rates of alcohol consumption, there was a reduced risk of incident diabetes in those who reported modest daily alcohol intake and were assigned to metformin or lifestyle modification. Moderate daily alcohol intake is associated with lower insulin secretion-an effect that warrants further investigation. This trial was registered at clinicaltrials.gov as NCT00038727.

Actos Now for the prevention of diabetes (ACT NOW) study

BACKGROUND

Impaired glucose tolerance (IGT) is a prediabetic state. If IGT can be prevented from progressing to overt diabetes, hyperglycemia-related complications can be avoided. The purpose of the present study was to examine whether pioglitazone (ACTOS) can prevent progression of IGT to type 2 diabetes mellitus (T2DM) in a prospective randomized, double blind, placebo controlled trial.

METHODS/DESIGN

602 IGT subjects were identified with OGTT (2-hour plasma glucose = 140-199 mg/dl). In addition, IGT subjects were required to have FPG = 95-125 mg/dl and at least one other high risk characteristic. Prior to randomization all subjects had measurement of ankle-arm blood pressure, systolic/diastolic blood pressure, HbA1C, lipid profile and a subset had frequently sampled intravenous glucose tolerance test (FSIVGTT), DEXA, and ultrasound determination of carotid intima-media thickness (IMT). Following this, subjects were randomized to receive pioglitazone (45 mg/day) or placebo, and returned every 2-3 months for FPG determination and annually for OGTT. Repeat carotid IMT measurement was performed at 18 months and study end. Recruitment took place over 24 months, and subjects were followed for an additional 24 months. At study end (48 months) or at time of diagnosis of diabetes the OGTT, FSIVGTT, DEXA, carotid IMT, and all other measurements were repeated.Primary endpoint is conversion of IGT to T2DM based upon FPG >or= 126 or 2-hour PG >or= 200 mg/dl. Secondary endpoints include whether pioglitazone can: (i) improve glycemic control (ii) enhance insulin sensitivity, (iii) augment beta cell function, (iv) improve risk factors for cardiovascular disease, (v) cause regression/slow progression of carotid IMT, (vi) revert newly diagnosed diabetes to normal glucose tolerance.

CONCLUSION

ACT NOW is designed to determine if pioglitazone can prevent/delay progression to diabetes in high risk IGT subjects, and to define the mechanisms (improved insulin sensitivity and/or enhanced beta cell function) via which pioglitazone exerts its beneficial effect on glucose metabolism to prevent/delay onset of T2DM.

TRIAL REGISTRATION

clinical trials.gov identifier: NCT00220961.

Describing patterns of weight changes using principal components analysis: results from the Action for Health in Diabetes (Look AHEAD) research group

PURPOSE

To demonstrate how principal components analysis can be used to describe patterns of weight changes in response to an intensive lifestyle intervention.

METHODS

Principal components analysis was applied to monthly percent weight changes measured on 2,485 individuals enrolled in the lifestyle arm of the Action for Health in Diabetes (Look AHEAD) clinical trial. These individuals were 45 to 75 years of age, with type 2 diabetes and body mass indices greater than 25 kg/m(2). Associations between baseline characteristics and weight loss patterns were described using analyses of variance.

RESULTS

Three components collectively accounted for 97.0% of total intrasubject variance: a gradually decelerating weight loss (88.8%), early versus late weight loss (6.6%), and a mid-year trough (1.6%). In agreement with previous reports, each of the baseline characteristics we examined had statistically significant relationships with weight loss patterns. As examples, males tended to have a steeper trajectory of percent weight loss and to lose weight more quickly than women. Individuals with higher hemoglobin A(1c) (glycosylated hemoglobin; HbA(1c)) tended to have a flatter trajectory of percent weight loss and to have mid-year troughs in weight loss compared to those with lower HbA(1c).

CONCLUSIONS

Principal components analysis provided a coherent description of characteristic patterns of weight changes and is a useful vehicle for identifying their correlates and potentially for predicting weight control outcomes.

Treatment of hypothalamic obesity with caffeine and ephedrine

OBJECTIVE

To investigate the hypothesis that the peripheral actions of caffeine and ephedrine to increase sympathetic tone and metabolic rate and to preserve lean tissue will cause weight loss in patients with hypothalamic obesity.

METHODS

We present 3 case studies of consecutive patients who presented with hypothalamic obesity and were treated with caffeine (200 mg) and ephedrine hydrochloride (25 mg) 3 times a day.

RESULTS

All patients were gaining weight at the time of initial assessment. The first patient lost 8% to 9% of her body weight and maintained that loss for the subsequent 2 years. The second patient lost 18.8% of her body weight and was maintaining a 9.5% weight loss after 6 years. The third patient lost 14% of her body weight during a 6-month period and gradually returned to her baseline weight during a period of 5 years, after which she was referred for bariatric surgical treatment.

CONCLUSION

These 3 patients with hypothalamic obesity, who had been steadily gaining weight, lost a mean of 13.9% of their body weight, and 2 of them maintained weight loss for a period of years. Thus, caffeine and ephedrine appeared to halt weight gain and maintain a clinically significant weight loss in 2 of our 3 patients. A randomized clinical trial to confirm these findings would be appropriate but difficult because of the rarity of this disorder.

Pioglitazone treatment in type 2 diabetes mellitus when combined with portion control diet modifies the metabolic syndrome

BACKGROUND

Treatment with thiazolidinediones (TZDs) produces weight gain.

OBJECTIVE

To test whether a portion control diet could prevent weight gain during treatment with pioglitazone in patients with type 2 diabetes mellitus (T2DM).

DESIGN

This 16-week randomized, open-label, parallel arm study compared three groups: (i) pioglitazone plus the American Diabetes Association diet (Pio + ADA); (ii) pioglitazone plus a portion control weight loss diet (Pio + PC); (iii) metformin plus the American Diabetes Association diet (Met + ADA). All participants received the same advice about calorie reduction, lifestyle change and exercise.

METHODS

Fifty-one men and women with T2DM, naive to TZDs, were randomized to a 16-week study. Pioglitazone (Pio) was titrated to a dose of 45 mg/day and metformin (Met) to a dose of 2 g/day. Fasting blood was collected for lipids, insulin and glycosylated haemoglobin A1c (HbA1c) at baseline and 16 weeks.

RESULTS

Forty-eight of fifty-one randomized subjects completed the study. Patients treated with Pio + ADA gained 2.15 +/- 1.09 kg (mean +/- SD) compared with a weight loss of 2.59 +/- 1.25 kg (p < 0.05) in the Pio + PC group, and a weight loss of 3.21 +/- 0.7 kg (p < 0.05) in the Met + ADA group. Waist circumference and visceral adipose tissue decreased significantly more in the Pio + PC group than in the Pio + ADA group. High-density lipoprotein cholesterol levels were significantly increased in the Pio + PC group compared with the Met + ADA group. Pioglitazone reduced insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR)) more than metformin. No significant differences between groups were seen for glucose, insulin, HbA1c or low-density lipoprotein cholesterol levels.

CONCLUSIONS

Pio + PC, prevented weight gain, reduced waist circumference and visceral fat compared with Pio + ADA diet.

Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates

BACKGROUND

The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year.

METHODS

We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content.

RESULTS

At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels.

CONCLUSIONS

Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize. (ClinicalTrials.gov number, NCT00072995.)

HF diets increase hypothalamic PTP1B and induce leptin resistance through both leptin-dependent and -independent mechanisms

Protein tyrosine phosphatase 1B (PTP1B) contributes to leptin resistance by inhibiting intracellular leptin receptor signaling. Mice with whole body or neuron-specific deletion of PTP1B are hypersensitive to leptin and resistant to diet-induced obesity. Here we report a significant increase in PTP1B protein levels in the mediobasal hypothalamus (P = 0.003) and a concomitant reduction in leptin sensitivity following 28 days of high-fat (HF) feeding in rats. A significant increase in PTP1B mRNA levels was also observed in rats chronically infused with leptin (3 microg/day icv) for 14 days (P = 0.01) and in leptin-deficient ob/ob mice infused with leptin (5 microg/day sc for 14 days; P = 0.003). When saline-infused ob/ob mice were placed on a HF diet for 14 days, an increase in hypothalamic PTP1B mRNA expression was detected (P = 0.001) despite the absence of circulating leptin. In addition, although ob/ob mice were much more sensitive to leptin on a low-fat (LF) diet, a reduction in this sensitivity was still observed following exposure to a HF diet. Taken together, these data indicate that hypothalamic PTP1B is specifically increased during HF diet-induced leptin resistance. This increase in PTP1B is due in part to chronic hyperleptinemia, suggesting that hyperleptinemia is one mechanism contributing to the development of leptin resistance. However, these data also indicate that leptin is not required for the increase in hypothalamic PTP1B or the development of leptin resistance. Therefore, additional, leptin-independent mechanisms must exist that increase hypothalamic PTP1B and contribute to leptin resistance.

The effects of dietary patterns on urinary albumin excretion: results of the Dietary Approaches to Stop Hypertension (DASH) Trial

BACKGROUND

Dietary studies designed to decrease the urinary albumin excretion rate (AER) typically reduce protein by increasing lower protein plant foods and decreasing higher protein animal products.

STUDY DESIGN

We evaluated AER while increasing protein intake in the Dietary Approaches to Stop Hypertension (DASH) Trial (randomized, parallel group, 8 week controlled feeding).

SETTING & PARTICIPANTS

378 individuals without diabetes with prehypertension or stage I hypertension.

INTERVENTION

The DASH diet, 18% energy from protein, emphasizes, among other features, low-fat dairy products; and the fruit/vegetable (FV) and control diets, each with 15% energy from protein.

OUTCOME

AER.

MEASUREMENTS

We measured AER by using immunoassay and covariates at baseline and after 8 weeks.

RESULTS

Baseline AER had a geometric mean value of 4.0 +/- 0.2 (SE) mg/24 h. In 285 participants with baseline AER less than 7 mg/24 h, AER was unchanged by diet treatment (geometric mean, 2.5 +/- 0.2 mg/24 h in the control diet, 3.0 +/- 0.2 mg/24 h in the FV diet, and 2.8 +/- 0.2 mg/24 h in the DASH diet). Conversely, in 93 participants with baseline AER of 7 mg/24 h or greater, end-of-feeding AER was lower in the FV diet (6.6 +/- 1.0 mg/24 h) than in the control (11.4 +/- 1.8 mg/24 h; P = 0.01) or DASH diets (11.7 +/- 1.6 mg/24 h; P = 0.005). The DASH and control diets were not different (P = 0.9).

LIMITATIONS

Long-term AER change not studied.

CONCLUSIONS

The decrease in AER after 8 weeks occurred in only those with high-normal baseline AER in the FV diet, in a pattern distinct from the blood pressure decrease. The DASH diet did not increase AER despite a 3% increase in energy from protein.

Relation of adipose tissue to metabolic flexibility

Metabolic flexibility is the capacity for skeletal muscle to shift reliance between lipids and glucose during fasting or in response to insulin. We hypothesized that body fat, adipose tissue characteristics, e.g. larger adipocytes, presence of inflammatory gene markers and impaired suppression of non-esterified fatty acids (NEFAs) during insulin infusion might be related to metabolic flexibility. We measured changes in respiratory quotient (DeltaRQ) before and during euglycemic-hyperinsulinemic clamp in healthy young males. Body fat by DXA, laboratory measurements, abdominal subcutaneous adipose tissue biopsies and fat cell size (FCS) were obtained after an overnight fast. Gene expression for 17 adipose tissue genes related to lipid synthesis, uptake, oxidation and storage, lipolysis and inflammation were measured. Reduced metabolic flexibility was associated with higher body fat, larger FCS and impaired insulin suppression of NEFAs. Metabolic flexibility was associated with higher serum adiponectin levels. Lower adipose tissue gene expression for inflammation markers was associated with greater NEFA suppression by insulin and metabolic flexibility. Combined, these results indicate that body fat, larger adipocytes, failure of insulin to suppress NEFAs, decreased adiponectin levels and inflammation markers in adipose tissue are associated with decreased insulin-stimulated glucose uptake and oxidation, which is an important component of reduced metabolic flexibility.

Triiodothyronine increases calcium loss in a bed rest antigravity model for space flight

Bed rest has been used as a model to simulate the effects of space flight on bone metabolism. Thyroid hormones accelerate bone metabolism. Thus, supraphysiologic doses of this hormone might be used as a model to accelerate bone metabolism during bed rest and potentially simulate space flight. The objective of the study was to quantitate the changes in bone turnover after low doses of triiodothyronine (T(3)) added to short-term bed rest. Nine men and 5 women were restricted to bed rest for 28 days with their heads positioned 6 degrees below their feet. Subjects were randomly assigned to receive either placebo or oral T(3) at doses of 50 to 75 microg/d in a single-blind fashion. Calcium balance was measured over 5-day periods; and T(3), thyroxine, thyroid-stimulating hormone, immunoreactive parathyroid hormone, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline were measured weekly. Triiodothyronine increased 2-fold in the men and 5-fold in the women during treatment, suppressing both thyroxine and thyroid-stimulating hormone. Calcium balance was negative by 300 to 400 mg/d in the T(3)-treated volunteers, primarily because of the increased fecal loss that was not present in the placebo group. Urinary deoxypyridinoline to creatinine ratio, a marker of bone resorption, increased 60% in the placebo group during bed rest, but more than doubled in the T(3)-treated subjects (P < .01), suggesting that bone resorption was enhanced by treatment with T(3). Changes in serum osteocalcin and bone-specific alkaline phosphatase, markers of bone formation, were similar in T(3)- and placebo-treated subjects. Triiodothyronine increases bone resorption and fecal calcium loss in subjects at bed rest.

Medications for weight reduction

Only two drugs are currently approved for long-term use in the treatment of obesity and four others for short-term use. Evaluating the risk-benefit profile is an essential first step. For individuals who have a low body mass index for whom the risk is small, the risk profile must make the drug acceptable for almost everyone. For higher-risk patients, such as those planning intestinal bypass or who have sleep apnea, a wider range of drugs may be considered. Obesity is a chronic disease that has many causes. Treatment is aimed at palliation-that is, producing and maintaining weight loss. Regardless of the primary site of action, the net effect must be a reduction in food intake or increase in energy expenditure.

Corrective responses in human food intake identified from an analysis of 7-d food-intake records

BACKGROUND

We tested the hypothesis that ad libitum food intake shows corrective responses over periods of 1-5 d.

DESIGN

This was a prospective study of food intake in women.

METHODS

Two methods, a weighed food intake and a measured food intake, were used to determine daily nutrient intake during 2 wk in 20 women. Energy expenditure with the use of doubly labeled water was done contemporaneously with the weighed food-intake record. The daily deviations in macronutrient and energy intake from the average 7-d values were compared with the deviations observed 1, 2, 3, 4, and 5 d later to estimate the corrective responses.

RESULTS

Both methods of recording food intake gave similar patterns of macronutrient and total energy intakes and for deviations from average intakes. The intraindividual CVs for energy intake ranged from +/-12% to +/-47% with an average of +/-25%. Reported energy intake was 85.5-95.0% of total energy expenditure determined by doubly labeled water. Significant corrective responses were observed in food intakes with a 3- to 4-d lag that disappeared when data were randomized within each subject.

CONCLUSIONS

Human beings show corrective responses to deviations from average energy and macronutrient intakes with a lag time of 3-4 d, but not 1-2 d. This suggests that short-term studies may fail to recognize important signals of food-intake regulation that operate over several days. These corrective responses probably play a crucial role in bringing about weight stability.

Central administration of the RFamide peptides, QRFP-26 and QRFP-43, increases high fat food intake in rats

Pyrogultamylated arginine-phenylalanineamide peptide (QRFP) is strongly conserved across species and is a member of the family of RFamide-related peptides, with the motif Arg-Phe-NH(2) at the C-terminal end. The precursor peptide for QRFP generates a 26-amino acid peptide (QRFP-26) and a 43-amino acid peptide (QRFP-43), both of which bind to the G protein-coupled receptor, GPR103. Recently, QRFP has been characterized in rats, mice and humans and has been reported to have orexigenic properties. In rodents, prepro-QRFP mRNA is expressed in localized regions of the mediobasal hypothalamus, a region implicated in feeding behavior. Increased intake of a high fat diet contributes to increased weight gain and obesity. Therefore, the current experiments investigated the effects of QRFP administration in rats and the effects of a high fat diet on prepro-QRFP mRNA and GPR103 receptor mRNA levels. Intracerebroventricular administration of QRFP-26 (3.0nM, 5.0nM) and QRFP-43 (1.0nM, 3.0nM) dose-dependently increased 1h, 2h, and 4h cumulative intake of high fat (55% fat), but not low fat (10% fat) diet. In Experiment 2, hypothalamic prepro-QRFP mRNA levels and GPR103 receptor mRNA levels were measured in rats fed a high fat or a low fat diet for 21 days. Prepro-QRFP mRNA was significantly increased in the ventromedial nucleus/arcuate nucleus of the hypothalamus of rats fed a high fat diet compared to those fed a low fat diet, while GPR103 mRNA levels were unchanged. These findings suggest that QRFP is a regulator of dietary fat intake and is influenced by the intake of a high fat diet.

Lifestyle and pharmacological approaches to weight loss: efficacy and safety

CONTEXT

Obesity results from a prolonged small positive energy balance, and its treatment needs to reverse this imbalance.

EVIDENCE ACQUISITION

Citations retrieved from PubMed and The Handbook of Obesity 2008 were selected to illustrate the points.

EVIDENCE SYNTHESIS

Many different diets have been tried to treat obesity, and weight loss occurs with all of them. There is currently no evidence that clearly supports a superiority of one macronutrient composition for diets used for weight loss. The principal effect seems to be the degree of adherence to the prescribed calorie reduction. Lifestyle strategies to modify eating behavior can be used in individual counseling sessions or in groups, both of which are important in helping patients modify their patterns of eating. Physical activity is particularly important in helping patients maintain a weight loss once achieved and is less valuable for weight loss itself. Food intake is controlled through many different mechanisms, but only a few drugs have been developed that tap these mechanisms. Orlistat, which blocks intestinal lipase, is one; sibutramine, a serotonin-norepinephrine reuptake inhibitor, is a second. Surgical approaches provide the most dramatic weight loss and have been demonstrated to reduce long-term mortality and reduce the incidence of diabetes.

CONCLUSIONS

Weight loss can be achieved by many methods, but the surgical procedures appear to be the most durable.