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Biomedical subjects

B J Rolls

Publications and source records attributed to B J Rolls.

At least 55 records · Page 3Linked to original sources
PubMed1995

Fat, carbohydrate, and the regulation of energy intake.

High-fat foods are readily overeaten. This could be because fat increases the palatability and energy density of foods or because fat has a low satiety value compared with carbohydrate. In several studies examining the effects of preloads that varied in fat and carbohydrate content on subsequent food intake, there was little difference in the effects of fat and carbohydrate on satiety. A dose-response preloading paradigm gives the most sensitive index of satiety. In one such test it was found that the effects of yogurts varying in fat or carbohydrate content did not differ in normal-weight, unrestrained men. However, in obese individuals or those concerned with body weight, fat in the yogurts was less effective in reducing subsequent food intake than carbohydrate. More studies are required to determine whether this small, but significant, insensitivity to energy from fat affects the regulation of food intake and body weight.

Body Weight↗
PubMed1995

Age-related impairments in the regulation of food intake.

Low food intake in elderly individuals increases the risk for many nutrition-related acute or chronic illnesses. It is not known whether aging is associated with changes in hunger and satiety, or whether elderly individuals can regulate energy intake in response to manipulations of the energy or nutrient content of foods. Therefore, this study investigated short-term energy regulation in healthy elderly (n = 16; aged 60-84 y) and young (n = 16; aged 18-35 y) men. Participants were given yogurt preloads that varied in energy and macronutrient content (low-fat, low-energy, 962 kJ; high-fat, high-energy, 2134 kJ; high-carbohydrate, high-energy 2134 kJ), or no yogurt, followed by a self-selected lunch (presented 30 min after subjects began to consume the yogurt). Energy intake, the percentage of macronutrients consumed in the meals, and subjective sensations of hunger and satiety were analyzed. The elderly men consumed significantly less energy than the young men in the baseline (no yogurt) condition. Lower intake was concordant with subjective sensations of satiety; visual analog data indicated that the older men were less hungry and more full at the start of lunch. Compensation for energy in the preloads was less precise in the elderly than in the young men, in that elderly men consistently overate at the self-selected lunch. Young men consumed +/- 10% total energy (lunch + yogurt) in the yogurt preload conditions compared with their baseline intake; elderly men overate between 10% and 30% in relation to their baseline intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Effect of meal macronutrient and energy content on human performance.

The effects of planned meals, varying in carbohydrate (CHO), fat and caloric content, on psychomotor performance by male subjects with unrestricted access to commercially-available foods was investigated in two residential studies. In the first study, two groups of three subjects (n = 6) completed psychomotor tasks before and after consuming a lunch consisting of 431 or 844 kcal, with caloric differences produced through covert changes in either fat or CHO content. The effects of each of four lunch conditions (low-fat, high-fat, low-CHO, high-CHO) were determined for three consecutive days. In the second study, two groups of three subjects (n = 6) received breakfast, lunch and an afternoon snack and completed psychomotor tasks after breakfast and lunch. Cumulative caloric content of the three eating occasions was approximately 700, 1200 or 1700 kcal (low, medium or high), again with differences resulting from covert changes primarily in either fat or CHO content. The effects of each of six food conditions were determined for two consecutive days. While changes in some aspects of performance were altered after meals, the effects were not related to the CHO, fat or caloric content of the meal. When subjects have unrestricted access to commercially-available foods, neither calories nor the relative fat or CHO content of normal meals influence human psychomotor task performance.

Adult↗
PubMed1994

Satiety after preloads with different amounts of fat and carbohydrate: implications for obesity.

High intake of dietary fat may be key in both the etiology and maintenance of obesity. Because a reduction in the proportion of energy derived from fat will be accompanied by an increase in the proportion of energy derived from carbohydrate, this study compared the effects of these macronutrients on eating behavior in obese and lean individuals. The effects of different amounts of fat and carbohydrate, covertly incorporated into yogurt preloads, on subsequent food intake, hunger, and satiety were assessed. A group of 12 normal-weight men, unconcerned about eating and body weight (unrestrained), accurately compensated for the energy in the preloads regardless of the nutrient composition. Other groups (n = 12 per group), including normal-weight restrained men and normal-weight and obese restrained and unrestrained females, did not show such orderly energy compensation; joule-for-joule, the high-fat preloads suppressed intake at lunch less than did high-carbohydrate preloads. These results suggest that a relative insensitivity to the satiating effect of fat could be involved in the development and maintenance of obesity.

Adult↗
PubMed1993

Appetite, hunger, and satiety in the elderly.

Food intake declines with age and the elderly frequently report a decrease in appetite. Social and physical factors as well as decreased energy expenditure may be part of the explanation for the decreased food intake; however, it is possible that changes in hunger mechanisms are also involved, but more studies similar to those conducted on thirst are needed. The consumption of a varied diet depends in part on sensory-specific satiety, that is, the decrease in the pleasantness of a food as it is consumed. We have shown that sensory-specific satiety changes with age such that it was absent in individuals over the age of 65 and this could be part of the explanation of why the elderly consume more monotonous diets. Additional basic studies on how aging affects the controls of food intake will suggest ways to improve the nutritional status of the elderly.

Aged↗
PubMed1992

National working conference on smoking and body weight. Task Force 1: Mechanisms relevant to the relations between cigarette smoking and body weight.

Careful, comprehensive, and empirical observations provide the building blocks of the sciences, whereas theory and mechanisms provide the "cement" to hold the blocks together and serve as blueprints to direct future building. This article resulted from several days of discussion regarding theories that may underlie the relation between cigarette smoking and body weight and the relation between smoking cessation and body weight. The working group composed of social and biological scientists who addressed this assignment considered what is already known within the smoking and body weight literature and also considered relevant findings from studies of smoking or body weight regulation that have not directly addressed the interaction of these variables. As expected, we were successful at listing some of what is not known and what is worth knowing. We also tried to identify fruitful possibilities for research activity that might clarify mechanisms of action and eventually lead to theoretical development. Because we do not believe that the present state of our deliberations merits the label of theories, we decided, instead, to report the summary of these deliberations as potential mechanisms relevant to the relation between smoking and body weight.

Adult↗
PubMed1992

Caloric, but not macronutrient, compensation by humans for required-eating occasions with meals and snack varying in fat and carbohydrate.

Six subjects participated in a residential study assessing the effects of covert macronutrient and energy manipulations during three required-eating occasions (breakfast, lunch, and afternoon snack) on total macronutrient and energy intakes. Overall, energy content of the occasions varied between approximately 3000 and approximately 7000 kJ (approximately 700 and approximately 1700 kcal) with the majority of the differential derived from either fat or carbohydrate (CHO). Each condition (high, medium, and low fat; high, medium, and low CHO; and no required eating) was examined for 2 d. Subjects compensated for the energy content of the required occasions such that only under the low-CHO condition (11,297 +/- 3314 kJ) was total daily energy intake lower than that observed in the absence of required occasions (13,297 +/- 1356 kJ). Only total energy intake under the high-fat condition (12,326 +/- 2548 kJ) was significantly different from its matched CHO condition (high-CHO condition: 14,665 +/- 2686 kJ). In contrast to the clear evidence for caloric compensation, there were no differential effects of condition on macronutrient intake, ie, there was no macronutrient compensation.

Adult↗
PubMed1992

Food intake, hunger, and satiety after preloads in women with eating disorders.

Food intake, food selection, macronutrient intake, sensory-specific satiety, and ratings of hunger and satiety were measured after high- and low-energy salad preloads (2414 kJ, or 172 kJ) or no preload to determine whether patients with eating disorders compensate appropriately for different energy intakes. Subjects were female patients with a DSM-III-R diagnosis of anorexia nervosa with bulimic features or bulimia nervosa, or non patient, normal-weight, nondieters (n = 9/group). At a self-selected lunch 30 min after the preloads, all of the groups reduced intake after the high-energy preload, with the bulimics showing the best compensation. The anorexics chose low-energy foods and in some conditions ate a smaller proportion of fat than did the other groups. The bulimics ate more high-energy foods than did the anorexics. The anorexics demonstrated sensory-specific satiety only after the high-energy salad and the bulimics only after the low-energy salad. Overall, these data suggest that while many of their responses to food are abnormal, patients with eating disorders have some capacity to respond to physiological hunger and satiety cues.

Adult↗
PubMed1992

Effects of olestra, a noncaloric fat substitute, on daily energy and fat intakes in lean men.

Nutrient and energy intakes, hunger, and fullness were examined after the replacement of 36, 20, or 0 g fat in breakfast with olestra, a noncaloric fat substitute. Twenty-four lean, nondieting men (aged 21-30 y) participated in a placebo-controlled, three-condition crossover design. Self-selected, ad libitum intakes at lunch and dinner were monitored in the laboratory. Evening snacks and breakfast the next day were assessed through food diaries. Visual-analog-scale ratings including hunger and fullness were collected throughout the test days. Single-meal olestra substitution produced a significant dose-related reduction in the amount and percentage of energy from fat consumed daily with a reciprocal increase in carbohydrate intake. Daily energy intakes were not significantly different nor did ratings of hunger and fullness vary systematically between conditions. Consumption of olestra can reduce fat intake and increase carbohydrate intake without affecting total daily energy intake or usual patterns of hunger and fullness.

Adult↗
PubMed1992

The influence of dietary fat on food intake and body weight.

Excessive intake of dietary fat is associated with a number of nutrition-related disorders, including obesity, heart disease, and cancer. The over-consumption of fat may be related to its palatability, high energy density, or physiological effects. This article reviews possible reasons why fat intake is high, examines the relationship between diet composition and body weight, and explores potential fat reduction strategies. It is concluded that low-fat or fat-free products could be useful in reducing the percentage of calories derived from fat, although this assertion needs to be further tested in controlled laboratory experiments and validated on a population basis.

Body Weight↗
PubMed1991

Eating behavior in eating disorders: response to preloads.

Eating behavior in eating-disordered subjects was investigated by recording food intake and subjective ratings following three preloads differing in calories, weight and connotation. Subjects were patients with a DSM-IIIR diagnosis of anorexia nervosa or bulimia nervosa and nonpatient volunteers (normal-weight or overweight dieters, and normal-weight nondieters). After all preloads, anorectics ate significantly less than all other subjects except normal-weight dieters, and anorectics rated hunger and desire to eat consistently lower and fullness greater than all other subjects. When analysis of intake was adjusted for body weight, anorectics and normal-weight dieters still consumed significantly less than controls. Anorectics selected foods that were lower in fat and carbohydrate and ate a larger proportion of calories as protein than the other subjects. All groups decreased subsequent intake after the high-calorie preload except bulimics. This study demonstrates that the regulatory capacity of eating-disordered individuals can be investigated and that aberrant eating behavior was observed.

Adult↗
PubMed1991

Failure of naltrexone to affect the pleasantness or intake of food.

Two separate studies were conducted to investigate the effects of oral naltrexone on the pleasantness ratings of foods and food intake. In both studies, normal-weight, nondieting males rated hunger, fullness, mood and the pleasantness of the taste of a variety of foods before and after double-blind administration of 50 mg of naltrexone or placebo. All subjects received a test meal, in a counterbalanced, repeated measures design. In the first study, 12 subjects were given a self-selection test meal after overnight deprivation. In the second study 14 subjects were given an ice cream test meal with no deprivation. In both experiments the pleasantness of the taste of the foods, sensory-specific satiety, hunger ratings and overall energy intake were not differentially influenced by naltrexone administration. In Experiment 2, intake of the ice cream was greater after active drug administration because subjects who received active drug on the first session ate less ice cream in the placebo session. In conclusion, in the short term, naltrexone had no impact on hunger, sensory-specific satiety or food intake.

Adolescent↗
PubMed1991

Meal order reversal: effects of eating a sweet course first or last.

The aim of the experiment was to determine the effects of eating a sweet food either as a first course or as a third course on intake during a three-course lunch. Twenty normal weight, non-dieting male subjects were run twice in a counter-balanced design. The first and third courses were interchanged and consisted of either a sweet (candy bar) or savory (cheese or crackers) food, both of similar palatabilities and energy densities. Intake of these foods, when they were eaten as a first course, was the same. The two first courses had no differential effects on intake of the middle course (spaghetti with meat sauce and a salad), which was the same in both conditions. Intakes in the third course did not differ significantly between conditions, but intake was slightly higher when the candy was eaten. Intake of the candy bar was similar in the first and third courses, but intake of the cheese on crackers was significantly lower (p less than 0.0007) as the third course. Total energy intake over the entire meal was 6% higher when the candy bar was eaten last, but this was not significant. Thus, there was no indication that eating candy as a first course affected appetite and food intake differently from eating the same amount of a non-sweet food such as cheese on crackers, which was similar in energy density and palatability. However, more studies with different foods in a situation more similar to a normal meal are needed before it can be concluded that sweet and savory foods at the start or end of a meal always have the same effects on appetite and food intake.

Adult↗
PubMed1991

Gender differences in eating behavior and body weight regulation.

Gender differences in food intake and selection first appear in adolescence. Men consume more calories than women, and the sexes have different eating styles, which indicate that women have been socialized to eat in a more feminine manner. Women experience more food-related conflict than men do, in that they like fattening foods but perceive that they should not eat them. Pressures to be thin are present in early adolescence, as noted by dieting behavior starting in very young girls. Women experience more dissatisfaction with their body weight and shape than men do. Sociocultural and psychological factors may be important in the etiology of eating disorders, which are much more prevalent in females than in males. Thus, further studies of gender differences in eating behavior will be important for understanding the etiology of eating and body-weight disorders and for designing gender-appropriate treatments.

Body Image↗
PubMed1991

Effects of intense sweeteners on hunger, food intake, and body weight: a review.

The sweet taste of aspartame, saccharin, and acesulfame-K has been reported to increase ratings of hunger and, after saccharin consumption, to increase food intake. However, most investigators have found that aspartame consumption is associated with decreased or unchanged ratings of hunger. Even if aspartame consumption increases ratings of hunger in some situations, it apparently has little impact on the controls of food intake and body weight. Aspartame has not been found to increase food intake; indeed, both short-term and long-term studies have shown that consumption of aspartame-sweetened foods or drinks is associated with either no change or a reduction in food intake. Preliminary clinical trials suggest that aspartame may be useful aid in a complete diet-and-exercise program or in weight maintenance. Intense sweeteners have never been found to cause weight gain in humans.

Aspartame↗