Drinking water is associated with weight loss in overweight dieting women independent of diet and activity

Background: Data from short‐term experiments suggest that drinking water may promote weight loss by lowering total energy intake and/or altering metabolism. The long‐term effects of drinking water on change in body weight and composition are unknown, however. Objective: This study tested for associations between absolute and relative increases in drinking water and weight loss over 12 months. Methods and Procedures: Secondary analyses were conducted on data from the Stanford A TO Z weight loss intervention on 173 premenopausal overweight women (aged 25–50 years) who reported <1 l/day drinking water at baseline. Diet, physical activity, body weight, percent body fat (dual‐energy X‐ray absorptiometry), and waist circumference were assessed at baseline, 2, 6, and 12 months. At each time point, mean daily intakes of drinking water, noncaloric, unsweetened caloric (e.g., 100% fruit juice, milk) and sweetened caloric beverages, and food energy and nutrients were estimated using three unannounced 24‐h diet recalls. Beverage intake was expressed in absolute (g) and relative terms (% of beverages). Mixed models were used to test for effects of absolute and relative increases in drinking water on changes in weight and body composition, controlling for baseline status, diet group, and changes in other beverage intake, the amount and composition of foods consumed and physical activity. Results: Absolute and relative increases in drinking water were associated with significant loss of body weight and fat over time, independent of covariates. Discussion: The results suggest that drinking water may promote weight loss in overweight dieting women.     

Health perceptions and demographic characteristics associated with underassessment of body weight

Objectives: To describe the relationship between BMI and perceived weight status and to determine how underassessment of weight status is associated with demographic characteristics, self‐reported general health, and perceived health risk in relation to one's body weight. Methods and Procedures: In the 2004 Styles surveys, 3,888 US adult participants described their current weight status (underweight, about right, slightly overweight, very overweight), which we compared with self‐reported BMI in order to determine concordance. We used multivariable logistic regression to evaluate associations between underassessment of body weight and characteristics of interest. Results: Among persons with a BMI ≥25, women were more likely than men to recognize their overweight status (slightly or very overweight; 93.0% of women vs. 73.5% of men) and the extent to which they were overweight: 70.4% of obese women vs. 49.5% of obese men described themselves as very overweight. Among the overweight and obese of both sexes, disagreement with regard to current weight as a health risk was associated with underassessment of weight. Additional factors associated with underassessment were education and race/ethnicity among overweight women; race/ethnicity among overweight men; household income and self‐rated health among obese women; and self‐rated health among obese men (P < 0.05). Discussion: While most of the obese participants recognized that they were overweight, many of them, particularly among the men, did not realize the extent to which they were overweight. Public health messages may be more effective if they are specifically tailored to target audiences, besides emphasizing the health risks associated with excess body weight.     

Evidence that obesity risk factor potencies are weight dependent, a phenomenon that may explain accelerated weight gain in western societies

Background

We have shown that individuals at the highest percentiles of the body mass index (BMI) distribution (i.e., most overweight) experience greater increases in body weight from sedentary lifestyle than those from the lowest percentiles. The purpose of the current analyses was to assess whether recent, accelerated increases in obesity could potentially be due to increased vulnerability to obesity risk factors as the population has become more overweight.

Methodology/Principal Findings

Quantile regression was used to compare BMI population percentiles to obesity risk factors (lower education, diets characterized by high-meat/low-fruit content, parental adiposity) in two independent samples of men (N₁ = 3,513, N₂ = 11,365) and women (N₁ = 15,809, N₂ = 10,159). The samples were subsets of the National Walkers'' (Study 1) and Runners'' (Study 2) Health Studies whose physical activities fell short of nationally recommended activity levels. The data were adjusted for age, race, and any residual effects of physical activity. The regression slopes for BMI vs. education, diet, and family history became progressively stronger from the lowest (e.g., 5^th, 6^th…) to the highest (e.g., …, 94^th, 95^th) BMI percentiles. Compared to the 10^th BMI percentile, their effects on the 90^th BMI percentile were: 1) 2.7- to 8.6-fold greater in women and 2.0- to 2.4-fold greater in men for education; 2) 3.6- to 4.8-fold greater in women and 1.7- to 2.7-fold greater in men for diet; and 3) 2.0- to 2.6-fold greater in women and 1.7-fold greater in men for family history.

Conclusions/Significance

Thus we propose risk factors that produce little weight gain in lean individuals may become more potent with increasing adiposity. This leads us to hypothesize that an individual''s obesity is itself a major component of their obesogenic environment, and that, the cycle of weight gain and increased sensitivity to obesity risk factors may partly explain recent increases in obesity in western societies.     

Influence of weekend lifestyle patterns on body weight

Objective: To determine whether alterations in diet and/or activity patterns during weekends contribute to weight gain or hinder weight loss. Methods and Procedures: Randomized, controlled trial comparing 1 year of caloric restriction (CR) with 1 year of daily exercise (EX). Subjects included 48 healthy adults (30F, 18M) aged 50–60 years with BMI 23.5–29.9 kg/m². Body weight was measured on 7 consecutive mornings for a total of 165 weeks at baseline and 437 weeks during the 1‐year interventions. Daily weight changes were calculated for weekends (Friday to Monday) and weekdays (Monday to Friday). Daily energy intake was estimated using food diaries; daily physical activity was measured using accelerometers. Both measures were validated against doubly labeled water (DLW). Results: At baseline, participants consistently gained weight on weekend days (+0.06 ± 0.03 kg/day, (mean ± s.e.), P = 0.02), but not on weekdays (?0.02 ± 0.02 kg/day, P = 0.18). This was attributable to higher dietary intake on Saturdays and lower physical activity on Sundays relative to weekdays (both P < 0.05). During the interventions, both CR and EX participants were in negative energy balance on weekdays (P < 0.005). On weekends, however, CR participants stopped losing weight, and EX participants gained weight (+0.08 ± 0.03 kg/day, P < 0.0001) due to higher dietary intakes on weekends. This helps to explain the slower‐than‐expected rate of weight loss during the interventions. Discussion: Alterations in lifestyle behaviors on weekends contribute to weight gain or cessation of weight loss on weekends. These results provide one explanation for the relatively slow rates of weight loss observed in many studies, and the difficulty with maintaining significant weight loss.     

Exercise effect on weight and body fat in men and women

Objectives: The effect of national exercise recommendations on adiposity is unknown and may differ by sex. We examined long‐term effects of aerobic exercise on adiposity in women and men. Research Methods and Procedures: This was a 12‐month randomized, controlled clinical trial testing exercise effect on weight and body composition in men (N = 102) and women (N = 100). Sedentary/unfit persons, 40 to 75 years old, were recruited through physician practices and media. The intervention was facility‐ and home‐based moderate‐to‐vigorous intensity aerobic activity, 60 min/d, 6 days/wk vs. controls (no intervention). Results: Exercisers exercised a mean 370 min/wk (men) and 295 min/wk (women), and seven dropped the intervention. Exercisers lost weight (women, ?1.4 vs. +0.7 kg in controls, p = 0.008; men, ?1.8 vs. ?0.1 kg in controls, p = 0.03), BMI (women, ?0.6 vs. +0.3 kg/m² in controls, p = 0.006; men, ?0.5 kg/m² vs. no change in controls, p = 0.03), waist circumference (women, ?1.4 vs. +2.2 cm in controls, p < 0.001; men, ?3.3 vs. ?0.4 cm in controls, p = 0.003), and total fat mass (women, ?1.9 vs. +0.2 kg in controls, p = 0.001; men, ?3.0 vs. +0.2 kg in controls, p < 0.001). Exercisers with greater increases in pedometer‐measured steps per day had greater decreases in weight, BMI, body fat, and intra‐abdominal fat (all p trend < 0.05 in both men and women). Similar trends were observed for increased minutes per day of exercise and for increases in maximal oxygen consumption. Discussion: These data support the U.S. Department of Agriculture and Institute of Medicine guidelines of 60 min/d of moderate‐to‐vigorous physical activity.     

Men Gain Additional Psychological Benefits by Adding Exercise to a Weight‐Loss Program

Objective: Adding exercise to a comprehensive weight‐loss program might not only attenuate any psychological distress associated with weight‐loss attempts but also may provide psychological benefits. This study examined whether a diet‐plus‐exercise weight‐loss program improved psychological outcomes more than a diet‐only weight‐loss program or an assessment‐only control group. Research Methods and Procedures: This study was part of a larger 1‐year randomized weight‐loss trial examining the effects of diet and exercise on cardiovascular disease risk factors in 264 overweight adults. Psychological measures specific to weight control (e.g., cognitive restraint, disinhibition, hunger, and body dissatisfaction) as well as traditional measures of psychological distress (e.g., symptoms of depression, anxiety, and stress) were obtained at baseline and 1 year. Results: Men and women in either weight‐loss program reported greater restraint, less disinhibition, and less hunger at 1 year than those in no program. Men in the diet‐plus‐exercise program experienced additional increases in restraint and decreases in hunger than did men in the diet‐only program. Women in the diet‐plus‐exercise program did not experience additional psychological benefits specific to weight control than those in the diet‐only program, despite increases in aerobic capacity. Discussion: The pattern seen for overweight men in the diet‐plus‐exercise program at 1 year—greater restraint, less disinhibition, and less hunger—is similar to the pattern seen in successful weight maintainers. These results underscore the need for innovative strategies that will enhance and sustain the pattern of psychological benefits specific to weight control associated with successful weight loss, especially for overweight women.     

The validity of obesity based on self-reported weight and height: Implications for population studies

Objective: To validate self‐reported information on weight and height in an adult population and to find a useful algorithm to assess the prevalence of obesity based on self‐reported information. Research Methods and Procedures: This was a cross‐sectional survey consisting of 1703 participants (860 men and 843 women, 30 to 75 years old) conducted in the community of Vara, Sweden, from 2001 to 2003. Self‐reported weight, height, and corresponding BMI were compared with measured data. Obesity was defined as measured BMI ≥ 30 kg/m². Information on education, self‐rated health, smoking habits, and physical activity during leisure time was collected by a self‐administered questionnaire. Results: Mean differences between measured and self‐reported weight were 1.6 kg (95% confidence interval, 1.4; 1.8) in men and 1.8 kg (1.6; 2.0) in women (measured higher), whereas corresponding differences in height were ?0.3 cm (?0.5; ?0.2) in men and ?0.4 cm (?0.5; ?0.2) in women (measured lower). Age and body size were important factors for misreporting height, weight, and BMI in both men and women. Obesity (measured) was found in 156 men (19%) and 184 women (25%) and with self‐reported data in 114 men (14%) and 153 women (20%). For self‐reported data, the sensitivity of obesity was 70% in men and 82% in women, and when adjusted for corrected self‐reported data and age, it increased to 81% and 90%, whereas the specificity decreased from 99% in both sexes to 97% in men and 98% in women. Discussion: The prevalence of obesity based on self‐reported BMI can be estimated more accurately when using an algorithm adjusted for variables that are predictive for misreporting.     

Gestational Diabetes and Postpartum Physical Activity: Evidence of Lifestyle Change 1 Year After Delivery

Although women with gestational diabetes mellitus (GDM) are advised to incorporate physical activity into their lifestyle in order to reduce their risk of developing type 2 diabetes (T2DM), it is recognized that new mothers face barriers to postpartum exercise. Thus, we sought to determine whether, following the diagnosis of GDM, women indeed alter their postpartum physical activity patterns, as compared to their peers without GDM. In this prospective observational cohort study, we assessed the physical activity patterns of 238 white women (58 with GDM, 180 without GDM) in the year before pregnancy and in the year following delivery, using the Baecke questionnaire, which evaluates the following three domains of physical activity: work, sport activity, and nonsport leisure‐time activity. Before diagnosis with GDM, women reported lower pregravid sport (P = 0.010) and leisure‐time activity (P = 0.013), compared to their peers without GDM. By 1 year postpartum, however, there were no longer significant differences between the GDM and non‐GDM groups in either sport or leisure‐time activity (P = 0.078 and P = 0.957, respectively). In particular, women with GDM significantly increased their leisure‐time activity over the first year postpartum (F = 10.1, P = 0.002), whereas the non‐GDM group did not (F = 0.00, P = 0.984). Indeed, on multiple linear regression analysis, GDM independently predicted an increase in leisure‐time activity between 1 year pregravid and 1 year postpartum (t = 2.55, P = 0.012). Furthermore, this significant relationship persisted even after adjustment for the finding of prediabetes/diabetes at 3 months postpartum (t = 2.83, P = 0.005). In conclusion, women with GDM successfully increased their leisure‐time activity in the first year postpartum, reflecting an element of lifestyle change following this diagnosis.     

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.     

The relationship of birth weight with longitudinal changes in body composition in adult women

Most research on birth weight and adult health status has reported adult measures at a single time point. This study examined the relationship of self‐reported birth weight to longitudinal changes in adult body composition in 587 women of the Michigan Bone Health and Metabolism Study, followed from 1992 to 2007 and aged 24–50 years at baseline. Linear mixed models were used to estimate the association between three birth weight categories and women's 15‐year changes in adult weight, height, BMI, waist and hip circumference, waist‐to‐hip ratio, and fat, lean, and skeletal muscle mass. Body composition measures increased in all women over the 15‐year study period. At their adult baseline, high birth weight women weighed 13% more and had waist circumference and lean mass measures that were 5.51 cm and 3.91 kg larger, respectively, than normal birth weight women. No differences were observed in adult body composition between low and normal birth weight women and rates of change in the adult measures did not vary across the birth weight groups. Women heavier at birth continued to be heavier through adulthood, corroborating previous reports based on single measures of adult body composition. Research to address whether higher adult body composition in high birth weight women increases the longitudinal risk for obesity‐related chronic diseases is needed.     

Prospective Investigation of Metabolic Characteristics in Relation to Weight Gain in Older Adults: The Hoorn Study

The objective of this investigation was to determine the relation between baseline glucose, insulin, adiponectin, and leptin levels and subsequent 6‐year weight and waist change in older men and women without diabetes in a prospective cohort study. Participants were 1,198 Dutch men and women without diabetes who were aged 50–77 years when baseline metabolic and anthropometric measurements were evaluated (1989–1991). Approximately 6 years later, body weight and waist circumference were re‐measured at a follow‐up examination (1996–1998). Metabolic variables (fasting plasma glucose, 2‐h postchallenge plasma glucose, homeostasis model assessment of insulin resistance (HOMA‐IR), adiponectin, and leptin) were evaluated as predictors of changes in weight and waist circumference. Postchallenge plasma glucose (mmol/l) significantly predicted less gain in both weight and waist circumference (β = ?0.28 kg, s.e. = 0.11; β = ?0.31 cm, s.e. = 0.14, respectively) during follow‐up. Leptin (µg/l) significantly predicted greater increases in weight (β = 0.29 kg, s.e. = 0.07) and waist (β = 0.16 cm, s.e. = 0.08) among men and in waist among women (β = 0.06 cm, s.e. = 0.02). Fasting plasma glucose (mmol/l) predicted an increase in waist among women (β = 1.59 cm, s.e. = 0.63), but not in men (β = ?0.74 cm, s.e. = 0.55). Adiponectin and insulin did not predict weight or waist change. The authors conclude that lower postchallenge plasma glucose and higher fasting leptin levels significantly predicted long‐term increases in weight and waist circumference. In contrast, measures of insulin resistance and adiponectin were not associated with weight change in this cohort of older persons without diabetes.     

Dietary patterns and changes in body weight in women

Objective: Our objective was to examine the association between adherence to dietary patterns and weight change in women. Research Methods and Procedures: Women (51,670, 26 to 46 years old) in the Nurses’ Health Study II were followed from 1991 to 1999. Dietary intake and body weight were ascertained in 1991, 1995, and 1999. A Western pattern, characterized by high intakes of red and processed meats, refined grains, sweets and desserts, and potatoes, and a prudent pattern, characterized by high intakes of fruits, vegetables, whole grains, fish, poultry, and salad dressing, were identified with principal component analysis, and associations between patterns and change in body weight were estimated. Results: Women who increased their Western pattern score had greater weight gain (multivariate adjusted means, 4.55 kg for 1991 to 1995 and 2.86 kg for 1995 to 1999) than women who decreased their Western pattern score (2.70 and 1.37 kg for the two time periods), adjusting for baseline lifestyle and dietary confounders and changes in confounders over time (p < 0.001 for both time periods). Furthermore, among women who increased their prudent pattern score, weight gain was smaller (multivariate‐adjusted means, 1.93 kg for 1991 to 1995 and 0.66 kg for 1995 to 1999) than among women who decreased their prudent pattern score (4.83 and 3.35 kg for the two time periods) (p < 0.001). The largest weight gain between 1991 and 1995 and between 1995 and 1999 was observed among women who decreased their prudent pattern score while increasing their Western pattern score (multivariate adjusted means, 6.80 and 4.99 kg), whereas it was smallest for the opposite change in patterns (0.87 and ?0.64 kg) (p < 0.001). Discussion: Adoption of a Western dietary pattern is associated with larger weight gain in women, whereas a prudent dietary pattern may facilitate weight maintenance.     

Sedentary behavior, recreational physical activity, and 7-year weight gain among postmenopausal U.S. women

Objective: To assess the relationship among recreational physical activity (PA), non‐occupational sedentary behavior, and 7‐year weight gain among postmenopausal U.S. women 40 to 69 years old. Research Methods and Procedures: In 1992 and 1999, 18,583 healthy female participants from the Cancer Prevention Study II Nutrition Cohort completed questionnaires on anthropometric characteristics and lifestyle factors. The associations between recreational PA [in metabolic equivalent (MET) hours per week] and non‐occupational sedentary behavior (in hours per day) at baseline and risk for 7‐year weight gain (5 to 9 or ≥10 vs. ±4 pounds) were assessed using multivariate logistic regression analysis. Results: Neither PA nor sedentary behavior was associated with a 5‐ to 9‐pound weight gain. Among women who were not overweight at baseline (BMI <25.0), the odds of ≥10‐pound weight gain were 12% lower (odds ratio, 0.88; 95% confidence interval, 0.77 to 0.99) for those in the highest category of recreational PA (≥18 MET h/wk) compared with >0 to <4 MET h/wk; odds were 47% higher (odds ratio, 1.47; 95% confidence interval, 1.21 to 1.79) for non‐overweight women who reported ≥6 h/d of non‐occupational sedentary behavior compared with <3 h/d. Neither PA nor sedentary behavior were associated with risk of ≥10‐pound weight gain weight among women who were overweight at baseline (BMI ≥25.0). Discussion: Both recreational PA and non‐occupational sedentary behavior independently predicted risk of ≥10‐pound weight gain among postmenopausal women who were not overweight at baseline. Public health messages to prevent weight gain among normal‐weight postmenopausal women may need to focus on decreasing time spent in sedentary behaviors and increasing the amount of time spent on PA.     

Self-selection accounts for inverse association between weight and cardiorespiratory fitness

Background: Men and women who exercise regularly and who are physically fit tend to be leaner than those who are sedentary and not fit. Although exercise is known to attenuate weight gain and promote weight loss, there may also be a propensity for leaner men and women to choose to exercise vigorously (self‐selection). Pre‐exercise body weights have been shown to account for all the weight differences between fast and slow walkers, but seem to account for only a portion of the weight differences associated with walking distances. Whether these results apply to maximum exercise performance (i.e., cardiorespiratory fitness) as well as to doses of vigorous exercise (metabolic equivalents >6) remains to be determined. Objective: Assess whether the cross‐sectional relationships of BMI to cardiorespiratory fitness and vigorous activity are explained by BMI prior to exercising. Methods and Procedures: Cross‐sectional study of the relationships between cardiorespiratory fitness (running speed during 10 km foot race) and vigorous physical activity (weekly running distance) to current BMI (BMI_current) and BMI at the start of running (BMI_starting) in 44,370 male and 25,252 female participants of the National Runners' Health Study. Results: BMI_starting accounted entirely for the association between fitness and BMI_current in both sexes, but only a quarter of the association between vigorous physical activity levels and BMI_current in men. In women, BMI_starting accounted for 58% of the association between BMI_current and vigorous activity levels. Discussion: Self‐selection based on pre‐exercise BMI accounts entirely for the association found between fitness and BMI (and possibly a portion of other health outcomes).     

Dietary fat and weight gain among women in the Nurses' Health Study

Objective: To assess the association of dietary fat and weight gain among adult women and to investigate whether offspring of overweight parents have a greater predisposition to weight gain due to intake of dietary fat. Research Methods and Procedures: This was an 8‐year follow‐up of 41,518 women in the Nurses’ Health Study (NHS), a population‐based, prospective cohort. The women were 41 to 68 years of age, free of cardiovascular disease, cancer, and diabetes in 1986 when “baseline” weight and diet were assessed. Eight years later (1994), changes in weight and dietary intake were assessed. Linear regression models were used to relate change in weight to fat intake and change in fat intake, using the percentage of energy from carbohydrate as the comparison, adjusted for age, BMI in 1986, leisure time physical activity, time spent sitting, percent of calories from protein, and change in percentage of calories from protein. Results: Overall, there was a weak positive association between total fat intake (β = 0.11) and weight gain. Increases in monosaturated and polyunsaturated fat were not associated with weight gain, but increases in animal fat, saturated fat, and trans fat had a positive association with weight change. There was not strong evidence of effect modification by parental weight status (p = 0.7 to 0.8 for percentage of calories from total fat, animal fat, and vegetable fat); however, the associations were stronger among the overweight compared with leaner women (p < 0.05 for percentage of calories from each type of fat). Among overweight women, for every one percentage increase in percentage of calories from trans fat, women gained an additional 2.3 lb (95% confidence interval, 1.80 to 2.86). Conclusion: Our results show that, overall, percent of calories from fat has only a weak positive association with weight gain; however, percentage of calories from animal, saturated, and trans fat has stronger associations. There was no clear evidence that the diet‐weight gain association was stronger among offspring of overweight parents, but dietary fat was associated with greater weight gain among overweight women.     

Four-year weight losses in the Look AHEAD study: factors associated with long-term success

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

Correlations with Self-Reported Weight Loss in Overweight U.S. Adults

The authors investigated two issues among overweight men and women in the U.S.: 1) what is the influence of the self-expressed intention to lose weight in the presence of other potential predictors of loss and 2) what are easily identifiable predictors of intentional weight loss during a 1-year recall period. The sample consisted of 1996 overweight men (body mass index (BMI ≥ 27.8 kg/m²) and 2586 overweight women (BMI ≥ 27.3 kg/m²) who answered questions regarding 1-year weight change in a Current Health Topic supplement of the population-based 1989 National Health Interview Survey. Of these overweight persons, 56.8% of men and 72.1% of women attempted to lose weight during the previous year. The most important characteristic associated with weight loss was the expressed intention itself. For any weight loss, the odds ratios (95% confidence intervals) for intention were 4.6 (3.6?5.9) for men and 3.8 (2.8?5.0) for women. Controlling for other factors reduced the odds only slightly, to 4.3 for men and 3.5 for women. Among women, older age, having a greater frequency of blood pressure checks, and being in poorer health reduced the influence of intent as a predictor of loss. To address the second objective, the identification of predictors of intentional 1-year weight loss, analysis was restricted to overweight persons who attempted to lose weight. For both sexes, statistically significant predictors (p<0.05) included never being married, smoking, higher BMI, being diabetic, and having a higher number of blood pressure checks. Being divorced or separated was predictive of weight loss in men only. Also, men were more likely to achieve weight loss than women. In conclusion, 1-year weight loss among the overweight was primarily a function of the intention to lose weight, although other factors contributed to determine whether weight loss was achieved.     

Personality disorders and body weight

We examine the impact of Axis II personality disorders (PDs) on body weight. PDs are psychiatric conditions that develop early in life from a mixture of genetics and environment, are persistent, and lead to substantial dysfunction for the affected individual. The defining characteristics of PDs conceptually link them with body weight, but the direction of the relationship likely varies across PD type. To investigate these links, we analyze data from Wave II of the National Epidemiological Survey of Alcohol and Related Conditions. We measure body weight with the body mass index (BMI) and a dichotomous indicator for obesity (BMI ≥ 30). We find that women with PDs have significantly higher BMI and are more likely to be obese than otherwise similar women. We find few statistically significant or economically meaningful effects for men. Paranoid, schizotypal, and avoidant PDs demonstrate the strongest adverse impacts on women's body weight while dependent PD may be protective against elevated body weight among men. Findings from unconditional quantile regressions demonstrate a positive gradient between PDs and BMI in that the effects are greater for higher BMI respondents.     

Neighborhood Socioeconomic Status in Relation to 10‐Year Weight Gain in the Black Women's Health Study

We prospectively assessed the association of neighborhood socioeconomic status (SES) with 10‐year weight change and with incident obesity among 48,359 women in the Black Women's Health Study (BWHS). Lower neighborhood SES was significantly associated with 10‐year weight gain after adjustment for individual SES and behavioral variables, such as physical activity and caloric intake. Low neighborhood SES was also associated with increased incidence of obesity during 10 years of follow‐up among women of normal weight at baseline (BMI <25 kg/m²). The associations were most evident among BWHS participants who had graduated from college. These prospective data suggest that lower neighborhood SES contributes to overweight and obesity in African‐American women.     

Factors predicting individual variability in diet-induced weight loss in MF1 mice

The effectiveness of caloric restriction (CR) as a treatment for obesity varies considerably between individuals. Reasons for this interindividual variation in weight loss in response to CR may lie in pre-existing individual differences and/or individual differences in compensatory responses. Here we studied the responses of 127 MF1 mice to 30% CR over four weeks, and investigated whether pre-existing differences or compensatory changes in body temperature, resting metabolic rate (RMR) and behavior explained the variation observed in body mass (BM) and fat mass (FM) changes. Mice showed considerable variation in BM loss (36-1%), and in the type of tissue lost (FM or fat free mass, FFM). About 50% of the variation in BM and FM loss could be predicted by pre-existing differences in food intake, RMR, and general activity, where BM loss was greater when food intake was lower and activity and RMR were higher. Compensatory changes in activity and body temperature together explained ~50% of the variation in BM and FM loss in both sexes. In models incorporating baseline variables and compensatory changes, food intake, and activity were the strongest predictors of weight loss in both sexes; i.e., lower baseline food intake and increased changes in activity resulted in greater BM and FM loss. Interestingly, increased baseline activity was a significant predictor of weight loss independent of compensatory changes in activity. Identifying factors involved in individual variability in weight loss may give insights into the mechanisms that underlie this variability, and is important to develop individually tailored weight-management strategies.