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Biomedical subjects

B J Rolls

Publications and source records attributed to B J Rolls.

At least 19 recordsLinked to original sources
PubMed2006

Retention rates and weight loss in a commercial weight loss program.

OBJECTIVE: To evaluate and describe retention rates and weight loss in clients participating in a commercial weight loss program. SUBJECTS: A total of 60 164 men and women ages 18-79 years who enrolled in the Jenny Craig Platinum program between May 2001 and May 2002. METHODS: Retention rates, mean weight loss and percent weight loss were calculated on a weekly basis for the 52-week period following initial enrollment in the weight loss program. Clients were categorized based on final week of participation in the program (weeks 1-4, weeks 5-13, weeks 14-26, weeks 27-39 and weeks 40-52) and weight loss was calculated at final week. A subgroup of clients was identified based on attendance through 13, 26 and 52 weeks. Mean and percent weight loss was calculated for these subgroups of clients. RESULTS: Of the 60 164 men and women who enrolled in the weight loss program, 73% were retained in the program after 4 weeks, 42% at 13 weeks, 22% at 26 weeks and 6.6% at 52 weeks. Clients who dropped out of the program during the first 4 weeks lost 1.1+/-1.6% (mean+/-s.d.) of their initial body weight, whereas clients who dropped out between 40 and 52 weeks lost 12.0+/-7.2%. Clients in the 13-week, 26-week and 52-week cohorts lost 8.3+/-3.3, 12.6+/-5.1 and 15.6+/-7.5% of their initial body weight, respectively. CONCLUSION: Weight loss was greater among clients who were retained in the program longer. The findings from this study suggest that a commercial weight loss program can be an effective weight loss tool for individuals who remain active in the program.

Adolescent↗
PubMed2002

Does nutrition information about the energy density of meals affect food intake in normal-weight women?

This study investigated whether the energy density of foods affected energy intake when subjects were informed about the energy density of their meals. Forty normal-weight women ate breakfast, lunch, and dinner in the laboratory on three separate days. The entrée at each meal was varied in energy density to be either 1.25, 1.50, or 1.75 kcal/g (5.23, 6.28, or 7.32 kJ/g), but was held similar in macronutrient composition and palatability. On each day, the entrées at all three meals had the same energy density. All entrées were consumed ad libitum. Subjects were assigned to one of two groups. Subjects in the information group received a nutrition label with each meal, which showed the energy density of the entrée. Subjects in the no-information group did not receive any nutrition information. The results revealed that subjects in both groups had the same pattern of food intake across the three levels of energy density. Energy density significantly affected energy intake; subjects in both groups combined consumed 22% less energy in the condition of low energy density than in the condition of high energy density (p < 0.0001). These findings show that energy density can have a significant influence on energy intake, even when individuals are informed about the energy density of their meals.

Adolescent↗
PubMed2001

Dysfunctional eating in the eating disorders.

Aberrant eating patterns in the eating disorders have been observed across various laboratory-based and clinical studies. It is now clear that problems in experiencing and expressing hunger, appetite, and satiety in anorexia and bulimia nervosa are likely to perpetuate the disorders once established. Whether problems in appetite regulation are primary or secondary to the development of the disorders is unknown. In studies examining indices of appetite regulation after treatment, there still remain significant levels of eating abnormality. This suggests that the main goals of treatment, including restoration of body weight in anorexia nervosa, abstaining from dieting in anorexia or bulimia nervosa, and reducing or abstaining from binge eating, do not correct some features of abnormal eating. The efficacy of nutritional counseling and specific nutritional management programs have been tested, and these seem to produce positive outcomes in improving eating behavior. Direct behavioral interventions to change eating patterns also have been examined, and these too seem to produce benefits that may be incorporated into CBT. Greater collaboration and cooperation between researchers and clinicians in addressing dysfunctional eating in the eating disorders will highlight improvements in treatment for identifiable eating abnormalities and will further the understanding of the human appetite system.

Cues↗
PubMed2001

Short-term effects of a progestational contraceptive drug on food intake, resting energy expenditure, and body weight in young women.

BACKGROUND: Studies showed that hormonal fluctuations that occur over the human menstrual cycle affect energy intake and expenditure. However, little is known about the possible effects on body weight regulation that may arise when these cyclic changes are suppressed with hormonal contraceptives. OBJECTIVE: The aim of this study was to examine how a progestational contraceptive drug (depot medroxyprogesterone acetate) affects food intake, resting energy expenditure (REE), and body weight in young women. DESIGN: Twenty normal-weight women were tested in a single-blind, placebo-controlled experiment. Body weight, REE, and 3-d food intake (food provided) were measured in the follicular and luteal phases of 2 menstrual cycles before a single injection of depot medroxyprogesterone or saline solution was administered. Measurements were also taken 4 times after injection: in the luteal and follicular phases of 2 cycles in the placebo group and 2 wk apart (to mimic timing of the menstrual phases) in the drug group. RESULTS: Before injection, the phase of the menstrual cycle affected both energy intake and REE. The study participants consumed more energy (4.3%; P = 0.02) and expended more energy at rest (4.3%; P = 0.0002) in the luteal phase than in the follicular phase. Comparison of pre- and postinjection means showed that treatment with the contraceptive drug had no significant effects on energy intake, REE, or body weight. CONCLUSIONS: This study showed that, although phases of the menstrual cycle affected energy intake and REE, depot medroxyprogesterone acetate did not alter energy intake or expenditure or cause weight gain in young women.

Adult↗
PubMed2001

Energy density of foods affects energy intake across multiple levels of fat content in lean and obese women.

BACKGROUND: The results of previous studies indicated that energy density, independent of fat content, influences energy intake. In most studies, however, both fat content and energy density were lower than in typical American diets. OBJECTIVE: We examined the influence of energy density on intake when fat content was above, below, or similar to the amount of fat typically consumed and when energy density was closer to that of American diets. DESIGN: Lean (n = 19) and obese (n = 17) women consumed all meals daily in our laboratory during 6 experimental sessions. The main entrées, consumed ad libitum, were formulated to vary in fat content (25%, 35%, and 45% of energy) and energy density (5.23 kJ/g, or low energy density, and 7.32 kJ/g, or high energy density) but to have similar palatability. RESULTS: Energy density influenced energy intake across all fat contents in both lean and obese women (P < 0.0001). Women consumed less energy in the low (7531 kJ) than in the high (9414 kJ) energy density condition. Despite this 20% lower energy intake, there were only small differences in hunger (7%) and fullness (5%). Women consumed a similar volume, but not weight, of food daily across conditions. Differences in intake by weight, but not volume, occurred because for some versions of manipulated foods, weight and volume were not directly proportional. CONCLUSIONS: Energy density affected energy intake across different fat contents and at levels of energy density comparable with those in typical diets. Furthermore, our findings suggest that cues related to the amount of food consumed have a greater influence on short-term intake than does the amount of energy consumed.

Adult↗
PubMed2000

Effects of acute food deprivation on eating behavior in eating disorders.

OBJECTIVE: Effects of acute food deprivation on eating behavior in bulimic patients and controls were investigated. It was predicted that food deprivation would increase overall food intake and result in overeating in bulimics. METHOD: Following 19 hr of food deprivation (in which breakfast and lunch were skipped), or no deprivation, food intake was measured in 9 inpatients with anorexia nervosa (binge eating/purging subtype, ANB), 10 inpatient (BN/in) and 9 outpatient (BN/out) normal-weight bulimics, and 11 unrestrained and 10 restrained controls. RESULTS: A general trend for increased food intake following deprivation was found. However, only BN/in patients consumed significantly more and selected higher energy foods following deprivation. ANB patients demonstrated the greatest degree of variability in intake and the least magnitude of change in ratings as a function of eating. DISCUSSION: A period of acute food deprivation did not trigger marked eating pathology as evidenced by overconsumption. Chronic dietary restraint may be a more potent precipitating factor in overeating than absolute number of hours of food restriction.

Adult↗
PubMed2000

Dietary approaches to the treatment of obesity.

According to the National Institute of Health guidelines for the treatment of overweight and obesity, the most important element in a weight loss program is the reduction in energy intake. Reducing the fat content of the diet and increasing physical activity without restricting energy intake are relatively inefficient methods of weight loss. Because individuals tend to consume a constant weight of food, the decrease in energy intake on a reduced-fat diet is likely related to the lower energy density of the diet. Diets of low energy density, which are typically low in fat and rich in complex carbohydrates, allow individuals to consume satisfying portions of food while reducing their energy intake. Because a wide variety of foods can be included in a diet that is low in energy density, this type of diet encourages the adoption of life-long eating habits that are integral to the maintenance of weight loss and the prevention of weight gain.

Adult↗
PubMed2000

Maintenance of dietary behavior change.

Reducing dietary fat, saturated fat, and sodium and increasing intakes of dietary fiber and fruits and vegetables are important for cardiopulmonary risk reduction. Behaviorally, these dietary changes are very challenging, and in different ways. Fewer than half of U.S. adults have diets meeting recommended intakes of these constituents, and many do not see a need to align their diets with recommendations. Various nutrition education and behavioral counseling approaches have been shown to facilitate changes in fat, fiber, sodium, and fruits and vegetables, but primarily in research settings and among the highly motivated. Practice-based and interdisciplinary studies are needed to refine strategies to effect long-term dietary changes, to differentiate behavioral issues for changes involving additions versus deletions from the diet, and to elucidate the roles of sensory, psychosocial, and contextual factors in adoption and maintenance.

Adolescent↗
PubMed2000

Increasing the volume of a food by incorporating air affects satiety in men.

BACKGROUND: Previous research indicated that increasing the volume of food by adding water can lead to reductions in energy intake. However, the addition of water affects not only the volume but also the energy density (kJ/g) of foods. No studies have examined the effect of volume independent of energy density on intake. OBJECTIVE: We examined the effect of food volume independent of energy density on satiety. DESIGN: In a within-subjects design, 28 lean men consumed breakfast, lunch, and dinner in the laboratory 1 d/wk for 4 wk. On 3 d, participants received a preload 30 min before lunch and on 1 d no preload was served. Preloads consisted of isoenergetic (2088 kJ), yogurt-based milk shakes that varied in volume (300, 450, and 600 mL) as a result of the incorporation of different amounts of air. Preloads contained identical ingredients and weighed the same. RESULTS: The volume of the milk shake significantly affected energy intake at lunch (P < 0.04) such that intake was 12% lower after the 600-mL preload (2966 +/- 247 kJ) than after the 300-mL preload (3368 +/- 197 kJ). Subjects also reported greater reductions in hunger and greater increases in fullness after consumption of both the 450- and 600-mL preloads than after the 300-mL preload. CONCLUSIONS: Changing the volume of a preload by incorporating air affected energy intake. Thus, the volume of a preload independent of its energy density can influence satiety.

Adult↗
PubMed2000

The role of energy density in the overconsumption of fat.

In recent years, research has focused on why fat is so readily overconsumed. Although the palatability of many high fat foods can encourage overconsumption, another possibility is that fat is not very satiating. A number of studies have compared the effects of fat and carbohydrate on both satiation (the amount eaten in a meal) and satiety (the effect on subsequent intake), but have found little difference between these macronutrients when the palatability and energy density were similar. On the other hand, the energy density of foods has been demonstrated to have a robust and significant effect on both satiety and satiation, independently of palatability and macronutrient content. It is likely that the high energy density of many high fat foods facilitates the overconsumption of fat. An understanding of the role that the energy density of foods plays in the regulation of food intake should lead to better dietary management of hunger and satiety in conditions associated with both over- and underconsumption of energy, such as obesity and anorexia.

Dietary Fats↗
PubMed1999

Do chemosensory changes influence food intake in the elderly?

Food intake declines with age, and elderly individuals frequently report a decrease in appetite. Changes in chemosensory systems may partially explain this low intake. However, few data have directly linked changes in gustatory or olfactory function to food choice or intake. In two studies, taste perception and preference were unrelated to sodium chloride or sugar intakes. Olfaction may be more affected by age than taste. Olfactory dysfunction is associated with decreased enjoyment of food, and adding odors to foods can increase intake in some elderly individuals. The consumption of a varied diet depends in part on sensory-specific satiety (a decrease in the pleasantness of a food as it is consumed). Sensory-specific satiety diminishes with age, and this could be part of the explanation of why some elderly individuals have little variety in their diets. However, the impact of chemosensory deficits on nutritional status depends on a number of social and environmental factors. For example, despite their age, financially secure, free-living healthy older men and women consumed more varied diets than young adults. Changes in mechanisms regulating food intake can make it difficult for some elderly individuals to maintain energy balance. When chemosensory impairments are combined with changes in food intake regulatory mechanisms, the risk for nutritional deficiencies may be high. If we are to optimize food intake and nutritional status in the elderly, additional basic studies on how changes in chemosensory systems associated with aging affect food selection and intake are required.

Aged↗
PubMed1999

Intake of fat and carbohydrate: role of energy density.

In this review, we consider two hypotheses which could explain why high-fat foods are overeaten. The first hypothesis is that fat is overeaten because it affects satiety and satiation less than carbohydrate. In several studies which have evaluated the effects of fat on satiety and satiation, fat differed little from carbohydrate when both the palatability and energy density of the test foods were matched. Therefore it is unlikely that the effects of fat on satiety or satiation provide the primary explanation for why it is overeaten. The second hypothesis is that the high energy density of fat facilitates its overconsumption. Support for this view comes from recent studies in which energy density significantly influenced intake when both the macronutrient content and palatability of the test foods were matched. For example, when individuals were fed diets varying in energy density and could eat as much food as they liked, they ate the same amount of food (by weight) so energy intake varied directly with energy density. Furthermore, when participants consumed foods of low energy density, they felt satisfied, despite reductions in energy intake. These findings show that energy density is a key determinant of energy intake in that cognitive, behavioral, and sensory cues related to the volume or weight of food consumed can interact with or override physiological cues associated with food intake.

Dietary Carbohydrates↗
PubMed1999

Energy density but not fat content of foods affected energy intake in lean and obese women.

BACKGROUND: Studies have shown that energy intake increases when both the fat content and energy density of the entire diet increases. When the fat content and energy density vary independently of one another, however, energy density, but not fat content, influences intake. OBJECTIVE: The present study examined whether energy intake in lean and obese women is affected when either the energy density or the fat content of a portion of the diet is manipulated and palatability is held constant. DESIGN: In a within-subjects design, 17 lean and 17 obese women consumed meals in the laboratory for four, 4-d test periods. In 3 of these test periods the energy density (4.4 and 6.7 kJ/g) or the fat content (16% and 36% of energy) of compulsory entrees representing 50% of each subject's usual energy intake was manipulated. Additional self-selected foods were consumed ad libitum at meals and as snacks. RESULTS: There were no systematic differences in palatability of the manipulated foods across conditions. Obese and lean participants responded similarly to the dietary manipulations. Intake of self-selected foods at meals was reduced significantly by 16% for both lean and obese subjects in the low- compared with the high-energy-density condition. The fat content of the compulsory foods had no significant effect on energy intake. Ratings of hunger did not differ between diets. CONCLUSION: These results indicate that when a portion of the diet was manipulated, the energy density, but not the fat content, of the foods affected total energy intake at meals in both lean and obese women.

Adolescent↗
PubMed1999

Water incorporated into a food but not served with a food decreases energy intake in lean women.

BACKGROUND: Previous research showed that decreasing the energy density (kJ/g) of foods by adding water to them can lead to reductions in energy intake. Few studies have examined how water consumed as a beverage affects food intake. OBJECTIVE: This study examined the effects of water, both served with a food and incorporated into a food, on satiety. DESIGN: In a within-subjects design, 24 lean women consumed breakfast, lunch, and dinner in our laboratory 1 d/wk for 4 wk. Subjects received 1 of 3 isoenergetic (1128 kJ) preloads 17 min before lunch on 3 d and no preload on 1 d. The preloads consisted of 1) chicken rice casserole, 2) chicken rice casserole served with a glass of water (356 g), and 3) chicken rice soup. The soup contained the same ingredients (type and amount) as the casserole that was served with water. RESULTS: Decreasing the energy density of and increasing the volume of the preload by adding water to it significantly increased fullness and reduced hunger and subsequent energy intake at lunch. The equivalent amount of water served as a beverage with a food did not affect satiety. Energy intake at lunch was 1209 +/- 125 kJ after the soup compared with 1657 +/- 148 and 1639 +/- 148 kJ after the casserole with and without water, respectively. Subjects did not compensate at dinner for this reduction in lunch intake. CONCLUSION: Consuming foods with a high water content more effectively reduced subsequent energy intake than did drinking water with food.

Adult↗
PubMed1999

Comparative lipid and lipoprotein responses to solid-food diets and defined liquid-formula diets.

BACKGROUND: Liquid-formula diets (LFDs) are useful in metabolic studies of the cholesterolemic effects of dietary lipids because they can be formulated with accuracy, facilitating precise delivery of fatty acids of interest. However, because of differences in composition and nutrient delivery between LFDs and solid-food diets (SFDs), there is a need to determine differences in their effects. OBJECTIVE: Our objective was to compare lipid and lipoprotein responses to changes in total fat, saturated fatty acids (SFAs), and cholesterol in subjects consuming an SFD or LFD. DESIGN: Twenty-one healthy subjects consumed controlled diets representative of an average American diet [AAD; 37% of energy from fat (15% from SFAs), and <50 mg cholesterol/MJ] or a National Cholesterol Education Program (NCEP) Step II diet [26% fat (5% from SFAs) and <25 mg cholesterol/MJ]. Other nutrients were similar between diets. Diets were consumed for 23 d in a randomized, crossover design. RESULTS: For the AAD and NCEP Step II diet, there were no significant differences in lipids and apolipoproteins when the LFD or SFD versions were consumed. In contrast, consumption of the SFD was associated with significantly lower total cholesterol and triacylglycerols than was consumption of the corresponding AAD or Step II LFD (P < 0.05). Subjective ratings of satiety, hunger, and quality of life between diet forms did not differ significantly. CONCLUSIONS: Both LFDs and SFDs yield quantitatively similar cholesterolemic responses to changes in dietary fat, SFAs, and cholesterol. LFDs may offer advantages because they provide easily administered, complete, balanced nutrition without affecting satiety.

Adult↗
PubMed1998

Sibutramine reduces food intake in non-dieting women with obesity.

Sibutramine (SIB), an inhibitor of serotonin and noradrenaline reuptake, has been shown in clinical trials to be associated with a dose-related decrease in bodyweight. This double-blind, placebo-controlled, Latin square crossover study examined whether the effect on bodyweight could be due in part to a reduction in daily food intake. Twelve non-dieting, women with obesity (body mass index of 30.5 to 41.9) received three treatments (0 [matching placebo], 10, or 30 mg SIB/day) for 14 days, with 14-day washout periods in between. On days 7 and 14, participants came to the laboratory to eat breakfast, lunch, and dinner so that daily energy and macronutrient intakes and ratings of hunger and satiety could be measured. Significant reductions occurred in food intake (both grams and energy) over the 14-day study period. On day 7, SIB 30 reduced intake significantly by 1762 kJ (23% reduction from placebo), and on day 14, both SIB 10 and SIB 30 significantly reduced intake compared with placebo (SIB 10, 19% reduction [1490 kJ]; SIB 30, 26% reduction [2079 kJ]). On day 7, the percentage of energy consumed from carbohydrate increased significantly with the 30-mg dose (56.7%) compared with that of placebo (51.4%), with a reciprocal decrease in energy from fat (27.8% to 24%). The results show that SIB reduced energy intake in women with obesity who were not attempting to lose weight.

Appetite Depressants↗