Stress does not affect ghrelin secretion in obese and normal weight women.

Stress has been supposed to increase appetite. The biological basis of this phenomenon may be a stress-induced alteration of the secretion of GUT peptides such as ghrelin. Stress-induced changes in ghrelin secretion could be a biological basis of overeating and a factor contributing to the development of obesity. Aim of the study was to analyze the effect of acute psychosocial stress on ghrelin secretion in obese and normal weight women. We compared pre- and postprandial plasma ghrelin secretion of 42 obese and 43 normal weight women in a randomized crossover design. Ghrelin and cortisol concentrations were measured and ratings of stress were also recorded in response to a psychological stressor (Trier Social Stress Test, TSST). Ghrelin samples were collected in the fasting state one time before participating in the TSST and one time before a control session. After the TSST, respectively, control session participants had a standardized ad libitum meal. 30 and 60 min after the TSST, respectively, control session preprandial ghrelin was measured again. Obese women showed lower pre- and postprandial release of ghrelin than normal weight controls. Moreover, obese women showed inhibited postprandial decrease of ghrelin secretion. Stress did not affect postprandial ghrelin secretion, but inhibited food intake in all subjects. The present data provide further evidence of altered ghrelin release in obesity. Acute stress did not affect postprandial ghrelin secretion, but inhibited food intake in all subjects. Results are discussed with regard to biological and psychological regulation of hunger and satiety in obesity.

Stress inhibits PYY secretion in obese and normal weight women.

The impact of stress on circulating levels of appetite-regulating hormones remains largely unknown. The aim of this study was to analyze the effect of acute psychosocial stress on the gut hormone peptide YY (PYY) secretion in obese and normal weight women. Therefore, we compared pre- and post-prandial plasma PYY secretion of 42 obese and 43 normal weight women in a repeated measure randomized controlled laboratory experiment. PYY and cortisol concentrations were measured and ratings of stress and satiety were also recorded in response to a psychological stressor (Trier Social Stress Test, TSST). PYY samples were collected in the fasting state both before participating in the TSST and before a control session. Participants had a standardized meal after the TSST and control session, respectively. PYY was measured both 30 and 60 min after the TSST and control session, respectively. Stress inhibited PYY secretion as well as food intake in all women, but did not influence subjective satiety perception. The present data indicate that despite of lower PYY levels the subjects' requirement to overeat was not increased. From an evolutionary perspective this finding is adaptive. After stress the organism is prepared for fight or flight reaction, whereas not primarily necessary functions are inhibited. Therefore, increased food intake during stress would be dysfunctional.

No evidence for effects of negative emotions on eating behaviour in overweight children.

Negative emotions have been hypothesised to trigger a short-term eating pattern in the obese that leads to a high calorie intake. The present study induced emotions of different quality (negative, neutral, positive) and compared laboratory eating behaviour in overweight and normal weight children. No significant emotion related differences in cumulative food intake curves during a laboratory meal were found. Results point to an adequate regulation of hunger and satiety in children, which possibly cannot be maintained during adulthood.

Stress-induced laboratory eating behavior in obese women with binge eating disorder.

OBJECTIVE: To compare the microstructural eating behavior of obese patients with and without binge eating disorder (BED) after stress induction in laboratory. METHOD: Forty-eight obese women were investigated. Seventeen were assigned to the group of BED. Group (BED vs. non-BED) by condition (stress vs. no stress) interaction effect on feeding variables, measured by a universal eating monitor, was tested. Stress was induced by the trier social stress test (TSST) and chocolate pudding served as laboratory food. RESULTS: From the nonstress to the stress condition, patients with BED, when compared with non-BED had a greater increase in average eating rate (p < .01) and a corresponding greater increase in the frequency of spoonfuls (p < .02). The BED group also showed a different change in acceleration/deceleration from the nonstress to the stress condition compared to the non-BED group (p < .04). DISCUSSION: Obese individuals with BED appear to exhibit a different response to stress than obese non-BED individuals and individuals with bulimia nervosa.

Resting metabolic rate in young women classified as restrained or unrestrained eaters.

Restrained eating involves a mainly cognitive control of eating behaviour and has been supposed to be a predisposing factor for the development of eating disorders. Biological correlates of the behaviour are expected, too. The present study investigated resting metabolic rate in 33 female restrained and unrestrained eaters. Measured by indirect calorimetry RMR showed a significant negative relationship to the degree of dietary restraint (controlled for BMI, partial r=-.46, p<.01). The lower energy requirements of restrained eaters might be genetically predisposed, but also might have severe consequences in nonclinical and clinical groups.

Laboratory eating behavior in obesity.

The eating behavior of 49 obese and 47 normal weight controls of both sexes was compared in laboratory. A universal eating monitor according to the Kissileff-instrument was used to obtain cumulative intake curves with chocolate pudding as laboratory food. Compared to controls the obese had a significantly higher initial eating rate (p<.002), larger spoonfuls (p<.005), and a greater total intake (p<.03) for the laboratory food. For initial eating rate a significant sex x weight interaction was found (p<.04). Higher values for males emerged only for overweight, but not for normal weight subjects. On the one hand, these data suggest an eating behavior of obese, which will promote a high energy intake in the natural environment. On the other hand, the observed differences can also be interpreted as a consequence of cognitive factors, impacting the eating behavior of obese under specific conditions.