The effects of ovarian hormones and emotional eating on changes in weight preoccupation across the menstrual cycle

Ovarian hormones (i.e., estradiol and progesterone) have recently been implicated in the etiology of eating disorders in women (1–4). Most research to date has focused on the role of ovarian hormones in risk for binge eating. This is not surprising given findings from animal studies demonstrating that ovarian hormones have direct, causal effects on food intake (5, 6). Specifically, removal of the source of ovarian hormones through bilateral ovariectomy in rats causes increased food intake, and adminstration of estradiol reverses this effect. In contrast, progesterone causes increased food intake, in part, by antagonizing the inhibitory effects of estradiol (6–8). In humans, food intake, binge eating, and emotional eating (i.e., the tendency to eat when experiencing negative emotions, 9) have been found to be significantly higher during the mid-luteal and pre-menstrual phases of the menstrual cycle as compared to the follicular/ovulatory phases (1, 3, 10–13). Studies that have directly examined estradiol and progesterone levels confirm that within-person changes in ovarian hormones account for these menstrual-cycle fluctuations (1, 3, 13). Specifically, while initial pilot data suggested that lower estradiol and higher progesterone levels were associated with increases in binge eating and emotional eating (1, 3), a recent study indicated that interactions between estradiol and progesterone (i.e., high levels of both) contribute to mid-luteal increases in emotional eating as well (14). Moreover, ovarian hormone/dysregulated eating associations have been shown to be stronger in women with clinically significant levels of binge eating compared to women without binge episodes (13). Importantly, in all previous studies, hormone effects on binge eating and emotional eating were independent of important covariates that also change across the menstrual cycle, including negative affect and body mass index (BMI) (1, 3, 13, 14). Far fewer studies, however, have examined menstrual cycle changes in other disordered eating variables. Broadening the phenotypes examined is important for developing more complete models of the role of ovarian hormones in the full spectrum of eating pathology. One particularly important set of variables to investigate are those related to weight concerns/preoccupation (i.e., intense preoccupation with weight, dieting, and the pursuit of thinness; 15). Weight concerns have been identified as one of the most robust prospective risk factors for the development of clinically significant eating disorders (16), and weight concerns are directly related to core symptoms (e.g., undue influence of body weight/shape on self-evaluation) of anorexia nervosa and bulimia nervosa (17). In the only previous report of its kind, Racine et al., (2012) examined the association between menstrual-cycle fluctuations in ovarian hormone and changes in weight concerns in two independent samples of women. In the first sample, robust fluctuations in weight preoccupation were observed across the menstrual cycle, where weight preoccupation levels were highest in the mid-luteal phase (4). Menstrual-cycle changes in weight preoccupation were primarily accounted for by within-person increases in progesterone and, to a lesser extent, decreases in estradiol. However, in a second sample, more modest, non-significant changes in weight preoccupation were observed across the menstrual cycle, and weight preoccupation was highest during the pre-menstrual phase. Reasons for the discrepant results across samples are unclear, although the very small sample sizes of these studies (N = 8 and N = 10, respectively) may have contributed to instability in effects. Clearly, additional research using larger samples of women is needed to clarify the presence/absence of within-person menstrual cycle fluctuations in weight preoccupation. Moreover, it will be important for these studies to determine whether menstrual cycle changes in weight preoccupation are due to changes in ovarian hormones, changes in psychological factors (e.g., increased negative affect), and/or changes in emotional eating that have been shown to fluctuate across the menstrual cycle in past research (1, 3, 13, 14, 18, 19). For example, emotional eating has previously been linked to ovarian hormones (1, 3, 13, 14), and we might expect weight concerns to increase during certain menstrual cycle phases as a result of emotional eating. Specifically, increased emotional eating during the mid-luteal phase could cause women to be more concerned and/or conscious about their body shape/weight; in this case, weight concerns may be due to eating in the presence of negative emotions rather than to changes in ovarian hormones. Thus, it is important to determine what factors might account for menstrual cycle changes in weight preoccupation: emotional eating, psychological factors (e.g., negative affect) and/or ovarian hormones. Given the above, the aim of the current study was to investigate within-person changes in weight preoccupation across the menstrual cycle utilizing a large, community-based sample of women. First, we were interested in examining whether levels of weight preoccupation significantly vary across the menstrual cycle. Second, we wanted to investigate whether within-person fluctuations in weight preoccupation across the menstrual cycle are best accounted for by within-person changes in ovarian hormones, negative affect, emotional eating, or a combination of these factors.