Reinhard J. Tuschl

A comparison of the validity of three scales for the assessment of dietary restraint.

The construct validity of Herman and Polivys Restraint Scale (RS), the restraint factor of the Three Factor Eating Questionnaire (TFEQ-R), and the restraint scale of the Dutch Eating Behavior Questionnaire (DEBQ-R) were investigated by relating these scales to self-reported mean caloric intake per day and to other measures associated with disordered eating and figure consciousness. A factor analysis showed that the three restraint scales measure different components of the restraint construct. A high score on the RS was closely related to consequences of mostly unsuccessful dieting, such as disinhibited eating and weight fluctuations, but not to successful overall caloric restriction in everyday life. High scores on the TFEQ-R and the DEBQ-R represented the more successful dieting behavior component of restraint. The three scales have in common a motivational component of restrained eating, including concerns about shape and weight, and desire for thinness.

Behavioral and biological correlates of dietary restraint in normal life

Based on laboratory results, restrained eating has been linked to the development of binge eating and eating disorder syndromes such as bulimia nervosa. This study was designed to extend the scope of investigation of the concept of restrained eating beyond the laboratory. Eating behavior and biochemical indices of nutritional state were investigated in 60 young women, who were divided in restrained and unrestrained eaters by questionnaire. Seven-day records of food intake showed that the high-restraint group ate around 400 kcal a day fewer than the low-restraint group. Group differences in actual macronutrient intake and long-term food preferences pointed to a qualitatively altered eating pattern in restrained eaters. Actual protein portion was higher in restrained eaters. They tried to avoid calorie dense food items of high carbohydrate and fat content. Instead, they preferred food regarded as low-caloric and healthy. Plasma levels of triiodothyronine and glucose, which could be taken as indices of long-term adaptation to starvation, were not decreased in the high-restraint group. However, significantly higher levels of triglycerides in restrained eaters may reflect a biological state due to short-term starvation. The results indicate that the concept of dietary restraint predicts eating behavior not only under experimental conditions, but also in normal life. As a consequence of altered eating patterns, psychological and physiological deprivation can be hypothesized in restrained eaters, making them prone to the occurrence of overeating.

From dietary restraint to binge eating: Some theoretical considerations

A correlation between dietary restraint and the occurrence of binge eating has been convincingly shown in several investigations. However, the mediating mechanisms have not yet been elaborated in detail nor linked to empirical evidence. This theoretical gap is addressed in the following. After a short review of behavioral and metabolic correlates of dietary restraint, potential effects of restrained eating on the psychophysiological regulation of food intake are described. These effects may lead to the disruption of intake regulation and therefore can be regarded as direct causes of binge eating.

Mood changes and physical complaints during the normal menstrual cycle in healthy young women.

Significant emotional and physical symptoms have been linked to hormonal changes during the menstrual cycle. A critical evaluation of the available studies questions the commonly held belief in menstrual-cycle-related complaints in the majority of normal women. The present study investigated changes in mood, somatic complaints and vegetative variables during the menstrual cycle in 30 healthy young women. Normal cycle function was evaluated and cycle phases were defined according to endocrine data. For all subjects, blood samples were taken at least three times a week to measure estradiol and progesterone. Daily ratings of psychological variables revealed no significant changes in global mood or depression over the cycle. Somatic complaints such as abdominal pain and breast tenderness were significantly related to the luteal, premenstrual, and menstrual phases. Appetite increased in the periovulatory and premenstrual phases. There was a tendency for sexual interest to be highest in the post-menstrual period. Affect and vegetative variables showed no association with hormone levels but were significantly correlated with subjective stress ratings. We conclude that in most healthy young women, cycle-related hormone fluctuations are not accompanied by marked affective changes. Specific physical complaints, however, do occur, particularly in the luteal, premenstrual, and menstrual phases.

Differences in food-choice frequencies between restrained and unrestrained eaters

Reported frequency of consumption for certain food items was studied in young normal-weight women, classified into 19 unrestrained and 20 restrained eaters by the Three-Factor Eating Questionnaire of Stunkard & Messick (1985). Neither group differed in the consumption of basic foods and snacks but restrained eaters showed a strong tendency to avoid fat. A large percentage of this group was used to consuming artificial sweeteners and other calorie-reduced foodstuffs. These qualitative alterations in the everyday eating behavior of restrained eaters may be one of the links between dietary restraint and binge eating.

Dieting causes menstrual irregularities in normal weight young women through impairment of episodic luteinizing hormone secretion

Thirteen healthy, normal weight young women were studied throughout a control cycle and a diet cycle, during which they lost 1kg per week on a vegetarian 800kcal diet. Blood was sampled daily in the morning, and at weekly intervals, collected at 10-minute intervals for 6 hours. Follicle growth was monitored by ultrasonic measurement. All subjects showed normal cyclic gonadal function during the control cycle. Cyclic gonadal function remained unaltered in two subjects during the diet cycle. No dominant follicle developed in seven others, while another four showed apparently normal follicular development but impaired progesterone secretion by the corpus luteum. Comparison of both cycles revealed that episodic luteinizing hormone (LH) secretion during the follicular phase was altered by dieting. Average LH concentrations and the frequency of episodic secretions were significantly reduced during the follicular phase but not during the luteal phase. Follicle-stimulating hormone was unaltered.

Endocrine findings in restrained eaters

Restrained (n = 9) and unrestrained eaters (n = 13) were selected from a group of healthy young women. Blood samples were collected overnight at half-hour intervals. Levels of cortisol, growth hormone, and glucose in both groups did not differ, while restrained eaters had significantly lower insulin values. After a standardized test meal of 500 kcal, restrained eaters had significantly lower norepinephrine values while insulin and glucose values did not differ from those of the unrestrained group. These findings indicate that restrained eating may have a biological basis.

Circadian pattern of large neutral amino acids, glucose, insulin, and food intake in anorexia nervosa and bulimia nervosa

Insulin, glucose, and large neutral amino acids (LNAA) were studied in 10 patients with anorexia nervosa, 13 patients with bulimia nervosa, and 15 healthy controls. Blood samples were collected at hourly intervals during the day and at two-hour intervals during the night over a 24-hour period. Ad libitum caloric and relative carbohydrate intake was significantly reduced in the anorectic and bulimic patients. Elevated concentrations of beta-hydroxybutyric acid (BHBA) were seen in the bulimic group, and low triiodothyronine (T3) concentrations in the anorectic group. Mean plasma glucose and insulin concentrations were significantly lowered in both groups. The tryptophan (Trp) to LNAA ratio was reduced in anorectic, but not in bulimic patients. These findings suggest that Trp influx into the brain is reduced in anorectic patients, possibly impairing central serotonergic function.

Serotonin turnover in rat brain during semistarvation with high-protein and high-carbohydrate diets

Serotonin (5-HT) and 5-hydroxyindolacetic acid (5-HIAA) were determined in seven brain regions of semistarved and control male rats. After semistarvation on a high carbohydrate diet serotonin turnover, as indicated by 5-HIAA/5-HT ratio, was increased in the total brain and several regions both three and 24 hours after the last meal. In contrast, after semistarvation on a high-protein diet serotonin turnover was decreased three hours after ingestion of the final meal, but increased 24 hours thereafter. Compulsary running wheel activity for one hour did not influence diet inducet changes in serotonin turnover. Alterations in plasma corticosterone during semistarvation were not related to changes in central serotonin turnover. Data suggest that the interaction of caloric restriction and diet composition determines serotonin turnover during semistarvation.

LUTEINIZING HORMONE AND FOLLICLE STIMULATING HORMONE SECRETION PATTERNS IN FEMALE ATHLETES WITH AND WITHOUT MENSTRUAL DISTURBANCES

Thirty‐one young female athletes and 13 age‐matched sedentary controls were studied throughout one menstrual cycle or over a 6 week period. Blood was sampled on 5 days per week. Episodic gonadotrophin secretion was measured in the early follicular phase and in the late luteal phase by blood sampling over a 12‐h period at 15‐min intervals. Eight athletes had anovulatory cycles, nine had impaired progesterone (P4) secretion during the luteal phase and 14 had normal cycles as judged from oestradiol (E2) and P4 plasma levels. Athletes with normal cycles had shorter cycles, lower E2 maxima at midcycle, and lower E2 and P4 concentrations during the luteal phase than had sedentary controls. Episodic luteinizing hormone (LH) secretion in the early follicular phase was significantly impaired in the anovulatory athletes: the average LH values over 12 h and the number of secretion episodes were significantly reduced. No significant changes were seen in follicle stimulating hormone secretion.