Harry R. Kissileff

The satiating efficiency of foods.

Experiments were undertaken to test the general hypothesis that some foods are more satiating than others, to find a mechanism for their differential satiating efficiencies, and to determine whether certain soups had a high enough satiating efficiency to recommend their addition to a meal as a way of reducing total caloric intake of that meal. In the first experiment it was found that intake of a test meal was lower after a large preload of tomato soup than after a small preload in women, but not in men. However, the total energy intake (soup plus test meal) was no less with meals which included the large soup preload than it was with meals that did not include a preload. Therefore adding a normal portion of tomato soup to a meal would not reduce its total energy intake. We noted the interesting incidental finding that total energy intake (i.e., preload plus test meal) of the meals which contained the larger amount of soup was less than the total energy intake of the meals which contained a combination of crackers , jelly, and juice. In the second experiment we confirmed this finding by showing that when equal weights of tomato soup preloads and a preload of crackers , cheese, and apple juice, which contains more energy, were given, total energy intake was less in meals which included soup. Therefore, substituting tomato soup for a more calorically dense first course could reduce total energy intake of that meal. In the third experiment, the hypothesis suggested by the second was confirmed. Two soups were more satiating than crackers , cheese, and juice. When two calorie levels were used for each preload, it was shown that calorie for calorie, these soups decreased intake of the test meal more than crackers , cheese, and juice. In the fourth experiment we showed that the mechanism for this differential satiating efficiency is not readily attributable to either bulk related factors or fat content. We suggest that the differential satiating efficiencies are related to differences in nutrient dispersion, orosensory cues, or temperature. Finally, reductions in intake were accompanied by reductions in the initial rate of eating and not by increases in the rate of deceleration. This reduction was small but consistent and suggests that foods which are more satiating reduce intake by decreasing desire to eat (i.e., hunger), not by accelerating the onset of meal termination (i.e., satiety). In fact the duration of meals was unaffected by the preloads.

A quadratic equation adequately describes the cumulative food intake curve in man.

A quadratic equation adequately describes the cumulative food intake curve in single-course meals in non-obese men and women. Intake of the meal and both the linear and quadratic coefficients of the equation were larger in absolute value in men than in women. The quadratic coefficient was negative. The coefficients have a simple physical interpretation. The linear coefficient is the initial rate of eating, and the quadratic is half the rate of deceleration (in absolute value). We can therefore say that men exhibit a higher initial rate of eating but also decelerate faster than women, on the test diet used in this study. There were no differences in intake or the coefficients of the cumulative intake curve owing to visual cues. It is suggested that this difference from other studies was because, in this study, the reservoir was wide, not narrow, and because visual cues operate to control intake only when they induce rapid changes in perception of the amount consumed. Finally, intake was less variable in the laboratory than it was outside the laboratory, but the sex difference in intake persisted outside the laboratory. It is suggested that the quadratic equation could be useful for characterizing factors that lead to changes in the rate of eating during the course of a meal and that such changes might have diagnositic value in assessing eating disorders.

A direct measure of satiety disturbance in patients with bulimia nervosa

To determine whether patients with bulimia nervosa (BN) experience the development of satiety during a meal differently than control subjects, a novel laboratory meal procedure was employed. Eleven women with BN and 11 women without eating disorders consumed a yogurt shake meal after being instructed to binge. After each 75-g increment consumed, the subjects were signaled by a tone to fill out a questionnaire on which they were asked to rate various sensations on visual analog scales. The sensations included Fullness, Hunger, Desire for a favorite food, Pleasantness of consuming the shake, Sickness, and having Enough to consume. Although patients, before purging, consumed significantly more food than the controls, who did not purge (1597 +/- 626.5 g vs. 1004 +/- 362.5 g, mean +/- SD), their final questionnaire ratings were not significantly different from the controls ratings. Patients ate significantly more than the controls before reaching 50% of their range of Hunger rating and 75% of their Full, Desire, Sick, and Enough rating ranges. The patients also ate significantly more than the controls between 75% and 100% of their Hunger rating range. These data suggest that one possible mechanism for overeating in patients with BN may be their failure to perceive or respond as normal subjects do to the range of sensations associated with satiety. Collecting ratings as a function of intake may provide a method for assessing and studying eating disturbances in clinical populations.

Satiating efficiency and a strategy for conducting food loading experiments.

The general hypothesis is proposed that foods vary along a small number of dimensions, such as nutrient composition, energy content, or weight, each of which makes a potentially measurable, but presently unknown, contribution to the satiation process. Because of the differential contributions of each of these dimensions (or factors), foods will vary in the effectiveness with which they induce satiety. Predictions of this hypothesis can best be tested by using the preloading strategy, in which preloads, varied along one dimension at a time, are given on different occasions in amounts which vary along the dimension being studied, and the experimental subject is permitted to eat the test meal following the preload until satiated. The contribution of that dimension is then assessed by the equation relating intake of the test meal to the magnitude of preload along the chosen dimension. The negative of the slope of the intake-preload equation is an index we call satiating efficiency of the magnitude of the satiating effect per unit of the chosen dimension. The satiating efficiency therefore provides a method of comparing the ability of different foods to induce satiety, along any dimension. This strategy can be used theoretically to measure the contribution of various dimensions of food to satiety. Practically it could be used to improve the satiating efficiency of foods designed for appetite control, by incorporating into the food, components which are high in satiating efficiency per unit of energy.(ABSTRACT TRUNCATED AT 250 WORDS)

Microstructural analyses of human ingestive patterns : From description to mechanistic hypotheses

Continuous automated weighing of food while subjects ate was used to test the hypothesis that failure to slow eating rate during a meal indicated a deficient response to satiety signals in obese patients. Cumulative intake curves were fitted to a quadratic equation. The physical form of the food and its palatability were a greater influence on the equations parameters than the subjects body weights, and the hypothesis was abandoned for several years (1984-1993). The hypothesis was revived with modifications when we discovered disturbances in eating behavior in patients with bulimia nervosa. The new hypothesis was that overeating was attributable to subjects inability to detect or respond to satiety-related signals after eating large amounts of food. Patients with eating disorders showed lower ratings of satiety after eating the same amounts of food as controls, but only after eating more than normal. In conclusion, microstructural examination of eating behavior may be more useful for tests of specific hypotheses about the control of eating than as a description of clinical disturbance.

Naltrexone and human eating behavior: A dose-ranging inpatient trial in moderately obese men

To investigate the effects of the long-acting opiate antagonist naltrexone on spontaneous human eating behavior, eight moderately obese male paid volunteers were housed in a hospital metabolic unit for 28 days and offered palatable foods ad lib by a platter service method. Under double-blind conditions, equally divided doses of 100, 200 and 300 mg naltrexone, or an acetaminophen placebo, were administered twice daily in tablet form for 3-day periods each, according to a Latin Square design. The doses of naltrexone resulted in decreases of daily caloric intake from placebo level, but these reductions were neither statistically significant nor dose-related. When the averaged effects of the doses were compared to placebo, five subjects showed intake reductions but the overall intake reduction of 301.5 +/- 198.1 kcal/day (mean +/- SEM) was not statistically significant. Naltrexone administration failed to selectively alter intakes of individual meals and snacks or macronutrient consumption patterns. During active drug periods, subjects lost 0.62 +/- 0.22 lb over 3 days, while during the placebo period, subjects gained 0.46 +/- 0.68 lb. However, there was no reliable change of basal metabolic rate as a function of naltrexone administration. The present results, which indicate that naltrexone administration is relatively ineffective in reducing food intake and inducing body weight loss in obese humans, are thus in contrast with reports that administration of opiate antagonist agents promote significant reductions of food intake and attenuations of body weight gain in experimental animals.

Behavioral assessment of satiety in bulimia nervosa

The abnormalities in eating behavior associated with bulimia nervosa suggest that patients with this illness may have a disturbance in satiety. The present study employed a six-meal protocol to assess satiety in both binge and non-binge eating episodes in women with bulimia nervosa and normal controls by examining whether an increase in the size of a soup preload led to a decrease in the amount of food consumed in a subsequent test meal. In control subjects, the increase in preload size was associated with an increase in fullness and a reduction in consumption of the non-binge test meal. Patients did not report consistent changes in ratings of hunger and fullness in response to the change in preload size, and few patients were able to complete the non-binge meals and refrain from vomiting afterwards. When instructed to binge eat, patients ate considerably more than control subjects, but patients did significantly reduce their intake of the test meal after the large compared to the small preload. These findings demonstrate that, although patients with bulimia nervosa exhibit abnormalities in the development of satiety, some mechanisms responsible for the control of food intake are functional during binge eating episodes.

Patterns of food selection during binges in women with binge eating disorder

OBJECTIVEnThe aim of this study was to determine whether temporal patterns of food selection during binges in obese subjects with binge eating disorder (BED) differ from those of patients with bulimia nervosa (BN).nnnMETHODnTen obese women with BED and 10 weight-matched women without BED each consumed a multiple-item meal identical to that used in previous studies with bulimics, and all subjects were instructed to binge. An experimenter recorded the subjects food choices every 10 s throughout the meal via a closed-circuit TV camera.nnnRESULTSnSubjects with BED consumed significantly more meat than subjects without BED (397.78 vs. 270.64 kcal), but the food choices and percentages of time spent eating each of the foods were similar among BED, non-BED, and normal weight controls. While bulimics ate dessert foods earlier in the meals, all other groups ate meat towards the beginning of their meal and ate more dessert foods towards the end of the meal.nnnDISCUSSIONnFood selection patterns during binges in subjects with BED are more similar to eating patterns of noneating disordered subjects, than to patterns seen in patients with BN. These data suggest that binge episodes between different groups of eating-disordered populations are qualitatively different.

Gastric compliance in bulimia nervosa

Bulimia nervosa (BN) is a psychiatric illness characterized by eating binges followed by inappropriate behavioral attempts to compensate for the binges, usually vomiting or laxative abuse. Patients with BN have disturbances in the development of satiety during a meal as well as disturbances in functions of the upper gastrointestinal tract such as slowed gastric emptying, impaired gastric accommodation reflex and blunted cholecystokinin release. The present study examined gastric compliance and sensory responses to gastric distention in women with BN and controls. Sixteen women with BN and 13 healthy control subjects swallowed an inflatable bag that was placed in the proximal stomach. The bag was inflated to produce increasing steps of pressure against the stomach wall, before and after consumption of a 200 ml (200 Kcal) liquid meal. Pressure and volume were recorded for 2-min periods, beginning at 0 mm Hg pressure and increasing in steps of 2 mm Hg until subjects reported discomfort, gastric volume reached 600 ml, or pressure reached 20 mm Hg. At each pressure step subjects made sensory ratings. Gastric compliance was calculated as the slope of the best-fit straight line of each subjects gastric volume vs. gastric pressure. There was a significant postmeal increase in gastric compliance in both groups of subjects but there was no difference in compliance between patients with BN and controls. Patients with BN appeared to have diminished sensitivity to gastric distention. In conclusion, although other studies have described gastrointestinal abnormalities associated with BN, the current study found gastric compliance of patients with BN to be normal.

A disturbance of gastric function in bulimia nervosa

BACKGROUNDnBecause the stomach plays an important role in the development of satiety, gastric function was examined in bulimia nervosa (BN).nnnMETHODSnSixteen patients with BN and 16 controls swallowed an inflatable bag, which was positioned in the proximal stomach. Minimal distending pressure (MDP), the pressure needed to overcome intraabdominal pressure, was determined. Gastric volume was recorded after subjects drank a liquid meal.nnnRESULTSnMDP was similar in patient and control groups (7.56 +/- 2.13 vs. 7.13 +/- 2.06 mmHg; t =.57, df = 30, p =.58). Average postmeal gastric relaxation was significantly lower in the patient group (29.7 +/- 97.8 vs. 105.1 +/- 103.3 mL; t = 2.13, df = 30, p =.042).nnnCONCLUSIONSnStomach relaxation following food consumption is significantly diminished in patients with BN. Physiologic abnormalities of stomach function in BN may contribute to the perpetuation of disturbances in behavior in this disorder.