In the 1950s, A.J. Stunkard initially described two forms of disordered eating patterns observed in obese persons—night eating (Stunkard, Grace, & Wolf, 1955) and binge eating (Stunkard, 1959). Although over 30 years passed before Stunkard’s astute observations stimulated much attention on these forms of disordered eating, both problems have witnessed a growth of research attention during the past decade (De Zwaan, Burgard, Schenck and Mitchell, 2003, Geliebter, 2002, Stunkard, 2001 and Stunkard and Allison, 2003).
Binge eating disorder (BED), has received more research attention than night eating, and was included in the DSM-IV (APA, 1994) in Appendix B reflecting “criteria sets provided for further study”. BED is characterized by recurrent binge eating without the compensatory weight control methods that distinguish bulimia nervosa. While unanswered questions remain regarding BED and its clinical features, empirical research has supported certain aspects of its validity as a disorder (Grilo, 1998, Grilo, 2003 and Grilo, Devlin, Cachelin and Yanovski, 1997).
In contrast to BED, the status of night eating in the various classification schemes remains that of a “syndrome”, and continues to be defined in various ways (Ceru-Bjork, Andersson, & Rossner, 2001). Night eating syndrome was first described by Stunkard et al. (1955) as consisting of morning anorexia, evening hyperphagia, emotional distress, and insomnia. Stunkard et al. (1996) revised the criteria for night eating syndrome to include the requirement that 50% of calories be consumed after 7 p.m. The night eating syndrome has recently received support from behavioral and neuroendocrine studies (Birketvedt et al., 1999). Relatedly, the American Sleep Disorders Association (1990) defined nocturnal eating syndrome as recurrent awakenings to eat followed by normal sleep following the eating behavior. Various “sleep-related” eating disorder syndromes have received preliminary attention (Schenck and Mahowald, 1994 and Winkelman, Herzog and Fava, 1999). As highlighted in previous reviews (Cerú-Björk, Andersson and Rössner, 2001, De Zwaan, Burgard, Schenck and Mitchell, 2003, Napolitano, Head, Babyak and Blumenthal, 2001 and Yager, 1999), these criteria have been inconsistently applied within each of the respective fields (eating/weight and sleep disorders) and remain of uncertain validity.
Except for the initial study by Stunkard et al. (1955), which reported a 64% rate of night eating syndrome in a sample of 25 severely obese patients, studies with obese patients have generally reported estimates ranging from 8% (Adami, Meneghelli, & Scopinaro, 1999) to 27% (Rand, Macgregor, & Stunkard, 1997) (see reviews by Ceru-Bjork et al., 2001 and Schenck & Mahowald, 1994). Studies of sleep-related eating problems have reported rates ranging from 8.7% (out-patient) to 16.7% (in-patient) among samples of patients with eating disorders (Winkelman et al., 1999).
The few studies of obese patients that have additionally assessed for BED have found that nocturnal eating and binge eating commonly co-occur (Greeno, Wing and Marcus, 1995, Napolitano, Head, Babyak and Blumenthal, 2001 and Stunkard, Berkowitz, Wadden, Tanrikut, Reiss and Young, 1996). In terms of the frequency of nocturnal eating in BED, two studies are relevant. Of the 79 obese women in the Greeno et al. (1995) study, 40 met criteria for BED, six met reported nocturnal eating, and all six of these women were among the subgroup with BED (15%). Stunkard et al. (1996) reported that six of 40 (15%) obese women with BED in a clinical trial met the full criteria for night eating syndrome. Napolitano et al. (2001) found that patients with both BED and nocturnal eating (N=13) reported greater psychological distress than patients who had either NE (N=13) or BED (N=23) alone.
These preliminary findings highlight the need for additional research on the extent and nature of the co-occurrence of night eating and BED (Geliebter, 2002, Stunkard, 2001 and Yager, 1999). This study aimed to examine the frequency of night-time eating (NE) and its correlates in a consecutive series of men and women with BED. For the purpose of this study, NE was based on a broad definition (waking up at night and eating) as assessed with the Eating Disorder Examination (EDE; Fairburn & Cooper, 1993. The EDE investigator-based interview determines the frequency of “nocturnal eating” without regard to additional proposed criteria from the night eating syndrome (Stunkard et al., 1996), or nocturnal eating syndrome or various sleep-related disorders (Schenck & Mahowald, 1994). Researchers have cogently argued for consideration of wide ranges including “sub-threshold” cases prior to reifying diagnostic constructs prematurely (Fairburn, Cooper and Shafran, 2003 and Grilo, Devlin, Cachelin and Yanovski, 1997). To avoid potential confusion with the various uses of the term “nocturnal” across the different literatures, we have selected the term night-time eating following a recent review (De Zwaan et al., 2003).
