Michael R. Lowe

The effects of dieting on eating behavior: a three-factor model.

I review and critique restraint theory and develop a 3-factor model of dieting behavior. The factors--frequency of dieting and overeating, current dieting, and weight suppression--are embedded within a 3-dimensional grid that also considers mechanisms mediating the effects of dieting and the influence of weight status. I argue that the eating behavior exhibited by restrained eaters stems from their frequent dieting and overeating in the past rather than from their current state of dietary or cognitive restraint. Evidence is reviewed, indicating that current dieting and weight suppression have different effects on eating than does restraint. The 3-factor model is used to reinterpret findings consistent with restraint theory and to explain findings inconsistent with restraint theory. Finally, clinical and research implications of the 3-factor model are discussed.

Are Dietary Restraint Scales Valid Measures of Acute Dietary Restriction? Unobtrusive Observational Data Suggest Not.

The finding that dietary restraint scales predict onset of bulimic pathology has been interpreted as suggesting that dieting causes this eating disturbance, despite the dearth of evidence that these scales are valid measures of dietary restriction. The authors conducted 4 studies that tested whether dietary restraint scales were inversely correlated with unobtrusively measured caloric intake. These studies, which varied in foods consumed, settings, and populations, indicated that common dietary restraint scales were largely uncorrelated with acute caloric intake. Results suggest that these scales are not valid measures of short-term dietary restriction and imply that it may be prudent to reinterpret findings from studies thai use these scales, including those that suggest dietary restraint is a risk factor for bulimic pathology.

The Power of Food Scale. A new measure of the psychological influence of the food environment.

This paper describes the psychometric evaluation of a new measure called the Power of Food Scale (PFS). The PFS assesses the psychological impact of living in food-abundant environments. It measures appetite for, rather than consumption of, palatable foods, at three levels of food proximity (food available, food present, and food tasted). Participants were 466 healthy college students. A confirmatory factor analysis replicated the three-factor solution found previously by Capelleri et al. [Capelleri, J. C., Bushmakin, A. G., Gerber, R. A., Leidy, N. K., Sexton, C., Karlsson, J., et al. (in press). Discovering the structure of the Power of Food Scale (PFS) in obese patients. International Journal of Obesity, 11, A165]. The PFS was found to have adequate internal consistency and test-retest reliability. The PFS and the Restraint Scale were regressed on four self-report measures of overeating. The PFS was independently related to all four whereas the Restraint Scale was independently related to two. Expert ratings of items suggested that the items are an acceptable reflection of the construct that the PFS is designed to capture. The PFS may be useful as a measure of the hedonic impact of food environments replete with highly palatable foods.

Multiple types of dieting prospectively predict weight gain during the freshman year of college

The freshman year of college is a period of heightened risk for weight gain. This study examined measures of restrained eating, disinhibition, and emotional eating as predictors of weight gain during the freshman year. Using Lowes multi-factorial model of dieting, it also examined three different types of dieting as predictors of weight gain. Sixty-nine females were assessed at three points during the school year. Weight gain during the freshman year averaged 2.1 kg. None of the traditional self-report measures of restraint, disinhibition, or emotional eating were predictive of weight gain. However, both a history of weight loss dieting and weight suppression (discrepancy between highest weight ever and current weight) predicted greater weight gain, and these effects appeared to be largely independent of one another. Individuals who said they were currently dieting to lose weight gained twice as much (5.0 kg) as former dieters (2.5 kg) and three times as much as never dieters (1.6 kg), but the import of this finding was unclear because there was only a small number of current dieters (N = 7). Overall the results indicate that specific subtypes of dieting predicts weight gain during the freshman year better than more global measures of restraint or overeating.

Psychometric analysis of the Three-Factor Eating Questionnaire-R21: results from a large diverse sample of obese and non-obese participants

Background:The 21-item Three-Factor Eating Questionnaire (TFEQ-R21) is a scale that measures three domains of eating behavior: cognitive restraint (CR), uncontrolled eating (UE) and emotional eating (EE).Objectives:To assess the factor structure and reliability of TFEQ-R21 (and if necessary, refine the structure) in diverse populations of obese and non-obese individuals.Design:Data were obtained from obese adults in a United States/Canadian clinical trial (n=1741), and overweight, obese and normal weight adults in a US web-based survey (n=1275). Confirmatory factor analyses were employed to investigate the structure of TFEQ-R21 using baseline data from the clinical trial. The model was refined to obtain adequate fit and internal consistency. The refined model was then tested using the web-based data. Relationships between TFEQ domains and body mass index (BMI) were examined in both populations.Results:Clinical data indicated that TFEQ-R21 needed refinement. Three items were removed from the CR domain, producing the revised version TFEQ-R18V2 (Comparative Fit Index (CFI)=0.91). Testing TFEQ-R18V2 in the web-based sample supported the revised structure (CFI=0.96; Cronbachs coefficient α of 0.78–0.94). Associations with BMI were small. In the clinical study, the CR domain showed a significant and negative association with BMI. On the basis of the web-based survey, it was shown that the relationship between BMI and CR is population-dependent (obese versus non-obese, healthy versus diabetics).Conclusions:In two independent datasets, the TFEQ-R18V2 showed robust factor structure and good reliability. It may provide a useful tool for characterizing UE, CR and EE.

Are Dietary Restraint Scales Valid Measures of Moderate- to Long-Term Dietary Restriction? Objective Biological and Behavioral Data Suggest Not

Prospective studies indicate that elevated scores on dietary restraint scales predict bulimic symptom onset, but experiments indicate that assignment to dietary restriction interventions reduces bulimic symptoms. One possible explanation for the inconsistent findings is that the dietary restraint scales used in the former studies are not valid measures of dietary restriction. The authors previously found that dietary restraint scales were not inversely correlated with objective measures of short-term caloric intake (E. Stice, M. Fisher, & M. R. Lowe, 2004). In this follow-up report, 3 studies indicated that the Three-Factor Eating Questionnaire dietary restraint scale was not correlated with doubly labeled water estimated energy intake over 2-week periods or with observationally measured caloric intake over 3 months. Results from this study and others suggest that dietary restraint scales may not be valid measures of moderate- to long-term dietary restriction and imply the need to reinterpret findings from studies that have used dietary restraint scales.

A self-report measure of social skill

Recent behavioral investigations into the assessment and modification of social skills have differed in two important ways from earlier conceptualizations of assertive behavior. First, some investigators are focusing their treatment strategies solely on the remediation of social behavior deficits and are ignoring the anxiety that may accompany such deficits. Second, interest in the assessment and modification of social skills is moving beyond the delimited area of assertive behavior to other types of social behavior. These trends suggest the need for an assessment device to measure a broad range of interactive variables. To meet this need, the Social Performance Survey Schedule (SPSS) was constructed. The SPSS contains descriptions of social behaviors whose frequency can be rated on a 5-point Likert scale. There are 50 positive and 50 negative items in the survey. Scoring may be adjusted to reflect standards of optimum social performance in a given population. Data on the reliability and validity of the SPSS are presented and clinical and research uses are discussed.

Weight-loss maintenance in overweight individuals one to five years following successful completion of a commercial weight loss program

OBJECTIVE: To determine weight loss maintenance among participants in a commercial weight loss program (Weight Watchers) who had reached their goal weights 1–5 y previously.DESIGN: A national sample (n=1002) was surveyed by phone to obtain demographic and weight-related information. An oversample (n=258) was recruited and weighed in person to develop a correction factor for self-reported weights in the national sample.RESULTS: Based on corrected weights, weight regain from 1 to 5 y following weight loss ranged between 31.5 and 76.5%. At 5 y, 19.4% were within 5 lb of goal weight, 42.6% maintained a loss of 5% or more, 18.8% maintained a loss of 10% or more, and 70.3% were below initial weight.CONCLUSIONS: These results are not directly comparable to those obtained in clinical settings because of differences in the populations studied. Nonetheless, they suggest that the long-term prognosis for weight maintenance among individuals who reach goal weight in at least one commercial program is better than that suggested by existing research.

Brain activation in restrained and unrestrained eaters: an fMRI study.

Restraint theory has been used to model the process that produces binge eating. However, there is no satisfactory explanation for the tendency of restrained eaters (REs) to engage in counterregulatory eating, an ostensible analogue of binge eating. Using functional magnetic resonance imaging (fMRI), the authors investigated brain activation of normal weight REs (N = 9) and unrestrained eaters (UREs; N = 10) when fasted and fed and viewing pictures of highly and moderately palatable foods and neutral objects. When fasted and viewing highly palatable foods, UREs showed widespread bilateral activation in areas associated with hunger and motivation, whereas REs showed activation only in the cerebellum, an area previously implicated in low-level processing of appetitive stimuli. When fed and viewing high palatability foods, UREs showed activation in areas related to satiation and memory, whereas REs showed activation in areas implicated in desire, expectation of reward, and goal-defined behavior. These findings parallel those from behavioral research. The authors propose that the counterintuitive findings from preload studies and the present study are due to the fact that REs are less hungry than UREs when fasted and find palatable food more appealing than UREs when fed.

Weight Suppression Is a Robust Predictor of Outcome in the Cognitive-Behavioral Treatment of Bulimia Nervosa

This study examined weight suppression (difference between highest premorbid weight and pretreatment weight) as a predictor of outcome in 188 outpatients with bulimia nervosa enrolled in a cognitive-behavioral therapy intervention. Participants who dropped out of treatment had significantly higher levels of weight suppression than treatment completers. Of participants who completed treatment, those who continued to engage in binge eating or purging had significantly higher levels of weight suppression than those who were abstinent from bingeing and purging. Results did not change when body mass index, dietary restraint, weight and shape concerns, or other relevant variables were controlled. Relinquishing bulimic behaviors and adopting normal eating patterns may be most feasible for patients who are closest to their highest premorbid weights.