A randomized controlled trial for obesity and binge eating disorder: Low-energy-density dietary counseling and cognitive-behavioral therapy
Highlights
► We examined the effects of dietary counseling for weight loss in BED. ► Dietary counseling was combined with CBT to also produce binge reduction. ► Weight loss, and improvements in binge eating and nutrition were observed. ► Binge eating was not exacerbated by dieting. ► There appeared to be a nutritional advantage for a diet low in energy density.
Introduction
Various health organizations now recommend a reduction in dietary energy density (kcal/g) for weight management (Centers for Disease Control and Prevention, 2008a, Centers for Disease Control and Prevention, 2008b, World Cancer Fund, 2007, World Health Organization, 2003). The main strategies for decreasing dietary energy density are to consume more water- and fiber-rich foods such as fruits and vegetables, and to decrease the proportion of fat (Duncan, Bacon, & Weinsier, 1983). Strategies for lowering dietary energy density allow for consumption of greater quantities of food while reducing energy intake and the associated reduction in hunger may for some individuals improve compliance with dietary recommendations. The purpose of the present research is to investigate the effects of a low-energy-density dietary approach in a population known to have difficulty with weight loss.
Binge eating disorder (BED) comprises a subset of overweight and obese individuals for whom weight loss in clinical trials has been an elusive goal. BED is characterized by recurrent binge eating, defined as eating an unusually large amount of food while experiencing a subjective sense of loss of control at least two days per week for at least a six-month duration, and not engaging in compensatory behaviors characteristic of bulimia nervosa (American Psychiatric Association, 2000). While obesity is not a diagnostic criterion for BED the two are strongly associated such that most persons with BED who present for treatment are obese and at increased risk for medical and psychiatric morbidity (Hudson, Hiripi, Pope, & Kessler, 2007). A number of psychotherapies (Wilson, Grilo, & Vitousek, 2007) and pharmacotherapies (Reas & Grilo, 2008) have been shown to produce significant and substantial reductions in binge eating and BED-related outcomes, but treatments tested to date have failed to produce significant or meaningful weight loss (Wilson et al., 2007). Cognitive behavior therapy (CBT) has emerged as the treatment of choice for BED, particularly because of its robust effects on reducing binge eating and improving the behavioral and psychological aspects of the disorder, despite its minimal effect on weight loss (Wilson et al., 2007).
A number of studies have directly compared CBT to behavioral weight loss treatments (BWLs) such as the LEARN Program for Weight Management (Brownell, 2000) and the National Institutes of Diabetes and Digestive and Kidney Diseases’s Diabetes Prevention Program (Grilo et al., 2005, Grilo et al., 2011, Munsch et al., 2007, Wilson et al., 2010). Collectively these studies have shown that CBT is superior to BWL in reducing and eliminating binge eating in BED. However, these studies have also reported minimal weight loss with BWL (Grilo and Masheb, 2005, Grilo et al., 2011, Munsch et al., 2007) and any short-term weight loss advantage for BWL over CBT appears to be lost at two-year follow-up (Wilson et al., 2010).
Studies have shown the effectiveness of lowering energy density for reducing energy intake in short-term laboratory studies (Bell et al., 1998, Bell and Rolls, 2001, Duncan et al., 1983, Rolls et al., 1999, Rolls et al., 1999, Rolls et al., 1997, Rolls et al., 2004), and more recently, for producing weight loss in longer-term efficacy (Ello-Martin et al., 2007, Rolls et al., 2005) and effectiveness (Lowe et al., 2008) trials. Treatment with strategies to lower-energy density, such as increased intake of fruits and vegetables, in combination with decreased fat intake, was shown to result in lower-energy intake and less hunger than a diet which emphasized decreased fat intake only (Ello-Martin et al., 2007).
Given that obese individuals with BED have increased gastric capacity compared to obese individuals without binge eating (Geliebter & Hashim, 2001) it seems logical to test whether such a dietary approach focused on greater food volume and lower caloric density might facilitate weight loss in this patient group. Preliminary support for this comes from a laboratory study that found individuals with BED reduced their energy intake with lower-energy-dense meals (Latner, Rosewall, & Chisholm, 2008) but this has not yet been tested as a clinical intervention. Thus, we performed a randomized, controlled trial to investigate a dietary approach – lowering energy density – for producing weight loss in obese patients with BED who also received CBT to address binge eating and BED-related outcomes. We additionally aimed to determine whether improvements in binge eating and BED-related outcomes could be achieved and sustained with dieting added to CBT, and to be the first treatment study of obese individuals with BED to examine dietary and metabolic outcomes.
Section snippets
Participants
Participants were adult patients who met DSM-IV-TR (American Psychiatric Association, 2000) criteria for BED, were recruited via print advertisements for treatment studies for binge eating and weight loss at a medical school, and were required to be aged 21–60, obese (body mass index (BMI) of 30 or greater) and available for the length of the treatment and follow-up at twelve-months. The study received full human subjects and ethics review, and approval by the University Institutional Review
Randomization and patient characteristics
Demographic and clinical characteristics are summarized in Table 1. Participants in the CBT + ED treatment group were older than participants in the CBT + GN group (M = 47.9, SD = 7.9 vs. M = 43.7, SD = 6.7; F(1, 49) = 4.13, p = 0.048), but the two groups did not differ significantly on any other demographic (gender, ethnicity, education) or clinical characteristics. Baseline ANOVAs were performed on all of the outcome variables listed in Table 2, Table 3, Table 4, and the two treatment groups did not differ
Discussion
The present study evaluated the efficacy of two dietary counseling approaches, when combined with CBT, to investigate binge eating, dietary and metabolic outcomes in a randomized clinical trial for BED. Eighty-six percent of randomized participants completed treatment, and of these, 30% achieved at least a 5% weight loss with rates of binge remission ranging from 55% to 75%. Dietary outcomes improved by the end of the study such that significant reductions were found for energy density, and
Conflicts of interest
The authors declared no conflicts of interest.
Acknowledgments
This research was supported by Grant R01MH082629 from the National Institutes of Health/National Institute of Mental Health awarded to Robin M. Masheb, Ph.D. The authors thank Ralitza Gueorguieva, Ph.D. (Yale School of Public Health) for her expert statistical consultation, Megan Roehrig, Ph.D. (Yale School of Medicine; now with the Department of Preventive Medicine at Northwestern University School of Medicine) for serving as project director, and Diane Mitchell, M.S. (Diet Assessment Center
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