Wiley

This article reviews information on discriminatory attitudes and behaviors against obese individuals, integrates this to show whether systematic discrimination occurs and why, and discusses needed work in the field. Clear and consistent stigmatization, and in some cases discrimination, can be documented in three important areas of living: employment, education, and health care. Among the findings are that 28% of teachers in one study said that becoming obese is the worst thing that can happen to a person; 24% of nurses said that they are “repulsed” by obese persons; and, controlling for income and grades, parents provide less college support for their overweight than for their thin children. There are also suggestions but not yet documentation of discrimination occurring in adoption proceedings, jury selection, housing, and other areas. Given the vast numbers of people potentially affected, it is important to consider the research‐related, educational, and social policy implications of these findings.

Parental feeding styles may promote overeating or overweight in children. A comprehensive literature review was undertaken to summarize the associations between parental feeding styles and child eating and weight status. Twenty‐two studies were identified. We systematically coded study attributes and outcomes and tested for patterns of association. Nineteen studies (86%) reported at least one significant association between parental feeding style and child outcome, although study methodology and results varied considerably. Studies measuring parental feeding restriction, as opposed to general feeding control or another feeding domain, were more likely to report positive associations with child eating and weight status. Certain associations differed by gender and by outcome measurement (e.g., rate of eating as opposed to total energy intake). Parental feeding restriction, but no other feeding domain, was associated with increased child eating and weight status. Longitudinal studies are needed to test underlying causal pathways, including bidirectional causal models, and to substantiate findings in the presence of other obesity risk factors.

Effective procedures are needed to prevent the substantial increases in adiposity that have been occurring among children and adults. Behavioral change may occur as a result of changes in variables that mediate interventions. These mediating variables have typically come from the theories or models used to understand behavior. Seven categories of theories and models are reviewed to define the concepts and to identify the motivational mechanism(s), the resources that a person needs for change, the processes by which behavioral change is likely to occur, and the procedures necessary to promote change. Although each model has something to offer obesity prevention, the early promise can be achieved only with substantial additional research in which these models are applied to diet and physical activity in regard to obesity. The most promising avenues for such research seem to be using the latest variants of the Theory of Planned Behavior and Social Ecology. Synergy may be achieved by taking the most promising concepts from each model and integrating them for use with specific populations. Biology‐based steps in an eating or physical activity event are identified, and research issues are suggested to integrate behavioral and biological approaches to understanding eating and physical activity behaviors. Social marketing procedures have much to offer in terms of organizing and strategizing behavioral change programs to incorporate these theoretical ideas. More research is needed to assess the true potential for these models to contribute to our understanding of obesity‐related diet and physical activity practices, and in turn, to obesity prevention.

Objective: Plasma concentrations of interleukin‐6 (IL‐6), a proinflammatory cytokine produced and released in part by adipose tissue, are elevated in people with obesity and type 2 diabetes. Because recent studies suggest that markers of inflammation predict the development of type 2 diabetes, we examined whether circulating plasma IL‐6 concentrations were related to direct measures of insulin resistance and insulin secretory dysfunction in Pima Indians, a population with high rates of obesity and type 2 diabetes.

Research Methods and Procedures: Fasting plasma IL‐6 concentrations (enzyme‐linked immunosorbent assay), body composition (DXA), insulin action (M; hyperinsulinemic euglycemic clamp), and acute insulin secretory responses to glucose (25 g intravenous glucose tolerance test) were measured in 58 Pima Indians without diabetes (24 women, 34 men).

Results: Fasting plasma IL‐6 concentrations were positively correlated with percentage of body fat (r = 0.26, p = 0.049) and negatively correlated with M (r = −0.28, p = 0.031), but were not related to acute insulin response (r = 0.13, p = 0.339). After adjusting for percentage of body fat, plasma IL‐6 was not related to M (partial r = −0.23, p = 0.089).

Discussion: Fasting plasma IL‐6 concentrations are positively related to adiposity and negatively related to insulin action in Pima Indians. The relationship between IL‐6 and insulin action seems to be mediated through adiposity.

Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age‐related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight‐management guidelines for obese older patients. The current data show that weight‐loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight‐loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.

Objective: To evaluate interactions among leptin, adiponectin, resistin, ghrelin, and proinflammatory cytokines [tumor necrosis factor receptors (TNFRs), interleukin‐6 (IL‐6)] in nonmorbid and morbid obesity.

Research Methods and Procedures: We measured these hormones by immunoenzyme or radiometric assays in 117 nonmorbid and 57 morbidly obese patients, and in a subgroup of 34 morbidly obese patients before and 6 months after gastric bypass surgery. Insulin resistance by homeostasis model assessment, lipid profile, and anthropometrical measurements were also performed in all patients.

Results: Average plasma lipids in morbidly obese patients were elevated. IL‐6, leptin, adiponectin, and resistin were increased and ghrelin was decreased in morbidly obese compared with nonmorbidly obese subjects. After adjusting for age, gender, and BMI in nonmorbidly obese, adiponectin was positively associated with HDLc and gender and negatively with weight (β = −0.38, p < 0.001). Leptin and resistin correlated positively with soluble tumor necrosis factor receptor (sTNFR) 1 (β = 0.24, p = 0.01 and β = 0.28, p = 0.007). In the morbidly obese patients, resistin and ghrelin were positively associated with sTNFR2 (β = 0.39, p = 0.008 and β = 0.39, p = 0.01). In the surgically treated morbidly obese group, body weight decreased significantly and was best predicted by resistin concentrations before surgery (β = 0.45, p = 0.024). Plasma lipids, insulin resistance, leptin, sTNFR1, and IL‐6 decreased and adiponectin and ghrelin increased significantly. Insulin resistance improved after weight loss and correlated with high adiponectin levels.

Discussion: TNFα receptors were involved in the regulatory endocrine system of body adiposity independently of leptin and resistin axis in nonmorbidly obese patients. Our results suggest coordinated roles of adiponectin, resistin, and ghrelin in the modulation of the obesity proinflammatory environment and that resistin levels before surgery treatment are predictive of the extent of weight loss after bypass surgery.

Objective: There are numerous methods of assessing overweight and obesity. We undertook an observational study to test a method of identifying overweight or obese patients solely by measuring the circumference of the neck.

Research Methods and Procedures: A test sample and a second validation sample included 979 subjects (460 men and 519 women), who visited a family medicine clinic in a southern Israeli urban district for any reason between the randomly chosen months of January and September 1998. Main outcome included neck, waist, and hip circumferences; body mass index (BMI); and waist:hip ratio measures.

Results: Pearson's correlation coefficients indicated a significant association between neck circumference (NC) and: BMI (men, r = 0.83; women, r = 0.71; each, p < 0.0001), age (men, r = 0.33; women, r = 0.36; each, p < 0.0001), weight (men, r = 0.7; women, r = 0.81; each, p < 0.0001), waist circumference (men, r = 0.86; women, r = 0.85; each, p < 0.0001), hip circumference (men, r = 0.62; women, r = 0.56; each, p < 0.0001), and waist:hip ratio (men, r = 0.66; women, r = 0.87; each, p < 0.0001). NC ≥37 cm for men and ≥34 cm for women were the best cutoff levels for determining the subjects with BMI ≥25.0 kg/m² using the receiver output curve analysis. In the validation unrelated group, the test characteristics were excellent with 98% sensitivity, 89% specificity, and 94% accuracy for men, and 100% sensitivity, 98% specificity, and 99% accuracy for women. NC ≥39.5 cm for men and ≥36.5 cm for women were the best cutoff levels for determining the subjects with BMI ≥30 kg/m² using the receiver output curve analysis. In the validation unrelated group, the test characteristics were excellent with 93% sensitivity, 90% specificity, and 91% accuracy for men, and 93% sensitivity, 98% specificity, and 97% accuracy for women.

Discussion: NC measurement is a simple and time‐saving screening measure that can be used to identify overweight and obese patients. Men with NC <37 cm and women with NC <34 cm are not to be considered overweight. Patients with NC ≥37 cm for men and ≥34 cm for women require additional evaluation of overweight or obesity status.

Objective: The longitudinal relationship between the consumption of energy‐dense snack (EDS) foods and relative weight change during adolescence is uncertain. Using data from the Massachusetts Institute of Technology Growth and Development Study, the current analysis was undertaken to examine the longitudinal relationship of EDS food intake with relative weight status and percentage body fat and to examine how EDS food consumption is related to television viewing.

Research Methods and Procedures: One hundred ninety‐six nonobese premenarcheal girls 8 to 12 years old were enrolled between 1990 and 1993 and followed until 4 years after menarche. At each annual follow‐up visit, data were collected on percentage body fat (%BF), BMI z score, and dietary intake. Categories of EDS foods considered were baked goods, ice cream, chips, sugar‐sweetened soda, and candy.

Results: At study entry, girls had a mean ± SD BMI z score of −0.27 ± 0.89, consumed 2.3 ± 1.7 servings of EDS foods per day, and consumed 15.7 ± 8.1% of daily calories from EDS foods. Linear mixed effects modeling indicated no relationship between BMI z score or %BF and total EDS food consumption. Soda was the only EDS food that was significantly related to BMI z score over the 10‐year study period, but it was not related to %BF. In addition, a significant, positive relationship was observed between EDS food consumption and television viewing.

Discussion: In this cohort of initially nonobese girls, overall EDS food consumption does not seem to influence weight status or fatness change over the adolescent period.

Objective: Investigation of the effect of a green tea‐caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake.

Research Methods and Procedures: A randomized placebo‐controlled double blind parallel trial in 76 overweight and moderately obese subjects, (BMI, 27.5 ± 2.7 kg/m²) matched for sex, age, BMI, height, body mass, and habitual caffeine intake was conducted. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM); during the WM period, the subjects received a green tea‐caffeine mixture (270 mg epigallocatechin gallate + 150 mg caffeine per day) or placebo.

Results: Subjects lost 5.9 ±1.8 (SD) kg (7.0 ± 2.1%) of body weight (p < 0.001). At baseline, satiety was positively, and in women, leptin was inversely, related to subjects’ habitual caffeine consumption (p < 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss (p < 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat, whereas resting energy expenditure was increased compared with a restoration of these variables with placebo (p < 0.01). In the high caffeine consumers, no effects of the green tea‐caffeine mixture were observed during WM.

Discussion: High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women. In habitual low caffeine consumers, the green tea‐caffeine mixture improved WM, partly through thermogenesis and fat oxidation.

Objective: Waist circumference has been proposed as a measure of obesity or as an adjunct to other anthropometric measures to determine obesity. Our objective was to examine temporal trends in waist circumference among adults in the U.S.

Research Methods and Procedures: We used data from 15, 454 participants ≥20 years old in National Health and Nutrition Examination Survey (NHANES) III (1988 to 1994) and 4024 participants ≥20 years old from National Health and Nutrition Examination Survey 1999 to 2000.

Results: The unadjusted waist circumference increased from 95.3 (age‐adjusted, 96.0 cm) to 98.6 (age‐adjusted, 98.9 cm) cm among men and from 88.7 (age‐adjusted 88.9 cm) to 92.2 (age‐adjusted 92.1 cm) cm among women. The percentiles from the two surveys suggest that much of the waist circumference distribution has shifted. Statistically significant increases occurred among all age groups and racial or ethnic groups except men 30 to 59 years old, women 40 to 59 and ≥70 years old, and women who were Mexican American or of “other” race or ethnicity.

Discussion: These results demonstrate the rapid increase in obesity, especially abdominal obesity, among U.S. adults. Unless measures are taken to slow the increase in or reverse the course of the obesity epidemic, the burden of obesity‐associated morbidity and mortality in the U.S. can be expected to increase substantially in future years.