The effects of stress on body weight: biological and psychological predictors of change in BMI.
OBJECTIVE
To investigate individual differences in the effects of stress on BMI.


METHODS
Participants were 71 healthy women volunteers enrolled in a university-based nurse practitioner program. Predictors of change in BMI were hypothesized to be cortisol secretion, dietary restraint, binging, mastery, mood, and eating attitudes. Measures were made at the beginning of the academic semester and 12 weeks later during the participants' examination period.


RESULTS
The women were of normal weight (BMI 25.2 +/- 4.3) for their age [43; standard deviation (SD), 7]. By the examination period, 40 had gained weight (mean, 5.5 pounds; SD, 2.2), 19 lost weight (mean, 2.5 pounds; SD, 1.5), and 12 had stable weight. BMI, salivary cortisol secretion, binging behavior, depression, and anxiety increased significantly, whereas scores on dietary restraint, weight, shape, and eating concerns, and mastery decreased significantly. Regression analysis showed that change in daily cortisol secretion significantly predicted change in BMI and that mastery significantly moderated this relationship. However, a reduction in dietary restraint was a perfect mediator of this relationship. Change in cortisol secretion also significantly predicted change in dietary restraint, and this was moderated by dietary restraint at the beginning of the academic semester. Reduction in dietary restraint was also predicted by a reduction in mastery and weight concern.


CONCLUSIONS
We identified individual differences that confer vulnerability to weight gain during stressful life events (dietary restraint and mastery). Given that women are exposed to daily stressors and use cognitive strategies to restrain their dietary intake, increasing awareness of the role of stress on eating behavior and weight is an important goal.
Roberts
Cliff
C
Kings College London, Institute of Psychiatry, London SE5 8AF, United Kingdom. cliff.roberts190@btinternet.com
Troop
Nicholas
N
Connan
Frances
F
Treasure
Janet
J
Campbell
Iain C
IC
D000328:Adult; D000339:Affect / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D015331:Cohort Studies; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008137:Longitudinal Studies; D008875:Middle Aged; D011237:Predictive Value of Tests; D012044:Regression Analysis; D013312:Stress, Physiological / Q000503:physiopathology* / Q000523:psychology*; D015430:Weight Gain / Q000502:physiology
D006854:Hydrocortisone