Association between melanocortin-4 receptor mutations and eating behaviors in obese patients: a case--control study.

Melanocortin-4 receptor (MC4R) gene mutations are involved in the leptin-melanocortin pathways that control food intake. The effect of these mutations on eating behavior phenotypes is still debated. To determine the association between functional MC4R mutations and eating behaviors, dietary intake and physical activity, we sequenced the MC4R gene in 4653 obese adults. Among them, 19 adults carriers of functional MC4R mutation were matched on age, sex and body mass index with two randomly-paired controls without MC4R mutation (n=57). We found that eating behaviors and physical activity did not differ between groups. In particular, cases were not at increased risk of binge eating disorders. Subjects carriers of MC4R mutation reported a higher proportion of dietary carbohydrates intakes (43.2±7.1 and 39.2±8.1% of total energy intake, respectively, P=0.048) and a lower proportion of dietary lipids (34.3±6.7 and 38.5±6.7% of total energy intake, respectively, P=0.018). In conclusion, mutation carriers differ from controls by a higher consumption of carbohydrates counterbalanced by a lower consumption of lipids expressed as percentage of total energy intake. However, functional MC4R mutations do not have a higher risk of compulsive eating contrary to what was previously suggested.

Eating behaviour in obese patients with melanocortin-4 receptor mutations: a literature review.

Melanocortin-4 receptor (MC4R) mutations are the most common known cause of monogenic obesity and an important contributor to polygenic obesity. MC4R mutations with partial or total loss of function, as well as the variant rs17782313 mapped near MC4R, are positively associated with obesity. MC4R is involved in the leptin-melanocortin signalling system, located in hypothalamic nuclei, that controls food intake via both anorexigenic or orexigenic signals. Impairment in this receptor might affect eating behaviours. Thus, in the case of MC4R mutation carriers, obesity could be related, at least partly, to inadequate control over eating behaviours. Many published studies address eating behaviours in MC4R mutation carriers. Most studies focus on binge eating disorder, whereas others examine various aspects of intake and motivation. Up to now, no evaluation of this literature has been performed. In this review, we examine the available literature on eating behaviours in carriers of MC4R mutations and variant rs17782313 near MC4R gene. We address binge eating disorder, bulimia nervosa, mealtime hyperphagia, snacking, psychological factors, satiety responsiveness and intake of energy and macro/micronutrient. In a small number of studies, MC4R mutations seem to impair eating behaviours or motivation, but no clear causal effects can be found in the balance of the evidence presented. Improvements in methodologies will be necessary to clarify the behavioural effects of MC4R mutations.

Effects of a 3-month supplementation with a novel soluble highly viscous polysaccharide on anthropometry and blood lipids in nondieting overweight or obese adults.

BACKGROUND: High viscosity fibre is known to exert many beneficial effects on appetite and metabolism. It could potentially help in weight management, in dieting or nondieting individuals. The present study investigated the effects of the daily intake of a novel high viscosity polysaccharide (HVP) over 3 months in nondieting obese or overweight men and women. METHODS: The study comprised a double-blind, randomised controlled clinical trial. Participants ingested 5-15 g per day of either HVP (n = 29, experimental group) or inulin (n = 30, control group) for 15 weeks. Changes in anthropometry (weight, waist and hip circumferences), blood lipids and glucose tolerance were studied from the beginning to the end of administration. Compliance and tolerance were examined. RESULTS: Differences appeared between HVP and inulin supplementation in female participants only. Mean (SD) decreases in body weight [1.6 (3.2) kg; approximately 2% of initial weight] and hip circumference [2.8 (3.6 ) cm] occurred in women of the HVP group but not in controls (Time × Group interactions, P ≤ 0.002). Total, high-density lipoprotein and low-density lipoprotein-cholesterol were lower at the end of supplementation in the women of the HVP group compared to controls (P ≤ 0.021). No effect appeared in waist circumference and triacylglycerol. No difference was noted in the number or severity of the adverse effects reported in both groups. Adverse effects were mild and agreed with commonly reported reactions to intake of dietary fibre. CONCLUSIONS: Beneficial although modest effects appeared after several weeks of daily HVP intake in nondieting obese or overweight women. The effects of HVP should be investigated in the context of a weight loss programme.

Schedule control of behavior reinforced by electrical stimulation of the brain.

Electrical stimulation of the brain was used to train rats to respond on random interval schedules. Stimulation was either delayed for 0.5 second and preceded by a brief signal, delayed and unsignaled, or presented contiguously with the response. In every case, responding was maintained on schedules and showed resistance to extinction typical of food-reinforced responding. Priming was never necessary. These data cast doubt on the generality of beliefs about the behavioral effects of brain stimulation reinforcement.

[Assessing various aspects of the motivation to eat that can affect food intake and body weight control]. / Deux questionnaires validés pour mesurer des aspects de la motivation à manger qui peuvent affecter le contrôle pondéral.

Over the last 30 years, several questionnaires have been developed and validated in order to assess many aspects of the motivation to eat that might be susceptible to impair adequate food intake and body weight control. A few of such questionnaires are described here, in particular, the "Three Factor Eating Questionnaire" also called the "Eating Inventory", and the "Dutch Eating Behavior Questionnaire". Critical aspects of the motivation to eat assessed by these tools are presented, such as dietary restraint, disinhibition, hunger, vulnerability to eat in response to external cues or emotional states, etc. These questionnaires were developed for use in the general population with the aim to identify critical aspects of the motivation to eat that might predispose to weight gain. They have been widely used in many countries and have allowed an improved understanding of the individual characteristics that predispose to body weight gain or resistance to weight loss. Originally, poor body weight control was attributed to a high level of dietary "restraint", or in other words, the tendency to deliberately restrict one's food intake for body weight control purposes. Such dietary restraint was suspected to lead to a number of physical and psychological difficulties, among which poor self-esteem and a paradoxical tendency to gain weight, resulting from the incapacity to maintain strict restraint over time. More recent studies have established that a motivational trait called "Disinhibition" is a strong predictor of body weight gain over time and of poor outcome of dieting. "Disinhibition" corresponds to a tendency to lose control over one's eating behavior and ingest excessively large quantities of food substances, in response to a variety of cues and circumstances. In addition to its untoward effect on weight, disinhibition also predicts various risk factors and pathologies, such as hypertension and diabetes. Other potentially critical dimensions for adequate body weight control are "emotional eating" and "externality", which represent an individual's vulnerability to eat in response to emotional states or external cues, respectively. These questionnaires have been translated into French and validated for the French population. Average data are available for normal weight and obese French men and women. A gender difference is often reported: women, and even young girls, tend to have higher scores than males for most dimensions. These questionnaires have been extensively used in populations without psychiatric disorders, with the only exception of diagnosed eating disorders such as anorexia and bulimia nervosa. The questionnaires have not been used until now in populations with other types of psychiatric disorders, such as schizophrenia or bipolar disease. Their relevance for such populations is now an important question, since last generation pharmaceutical treatments of such psychiatric disorders seem to adversely affect body weight control. It then becomes critical to know whether the psychological dimensions assessed by such questionnaires reflect the action of pharmacological agents that induce weight gain. A research project is now in progress at Sainte-Anne Hospital to investigate many dimensions of the motivation to eat, as assessed by the questionnaires, in psychiatric patients receiving various types of antipsychotic agents. The results of this original study might provide hints about the mechanisms that lead to body weight gain in patients receiving certain types of antipsychotic pharmacological agents and potentially help in preventing or reversing the weight gain associated with such treatments.

Plasma obestatin levels in normal weight, obese and anorectic women.

Obestatin is a recently discovered peptide produced in the stomach, which was originally described to suppress food intake and decrease body weight in experimental animals. We investigated fasting plasma obestatin levels in normal weight, obese and anorectic women and associations of plasma obestatin levels with anthropometric and hormonal parameters. Hormonal (obestatin, ghrelin, leptin, insulin) and anthropometric parameters and body composition were examined in 15 normal weight, 21 obese and 15 anorectic women. Fasting obestatin levels were significantly lower in obese than in normal weight and anorectic women, whereas ghrelin to obestatin ratio was increased in anorectic women. Compared to leptin, only minor differences in plasma obestatin levels were observed in women who greatly differed in the amount of fat stores. However, a negative correlation of fasting obestatin level with body fat indexes might suggest a certain role of obestatin in the regulation of energy homeostasis. A significant relationship between plasma obestatin and ghrelin levels, independent of anthropometric parameters, supports simultaneous secretion of both hormones from the common precursor. Lower plasma obestatin levels in obese women compared to normal weight and anorectic women as well as increased ghrelin to obestatin ratio in anorectic women might play a role in body weight regulation in these pathologies.

Intense sweeteners, energy intake and the control of body weight.

Replacing sugar with low-calorie sweeteners is a common strategy for facilitating weight control. By providing sweet taste without calories, intense sweeteners help lower energy density of beverages and some foods. Reduced dietary energy density should result in lower energy intakes--but are the energy reduction goals, in fact, achieved? The uncoupling of sweetness and energy, afforded by intense sweeteners, has been the focus of numerous studies over the past two decades. There are recurring arguments that intense sweeteners increase appetite for sweet foods, promote overeating, and may even lead to weight gain. Does reducing energy density of sweet beverages and foods have a measurable impact on appetite and energy intakes, as examined both in short-term studies and over a longer period? Can reductions in dietary energy density achieved with intense sweeteners really affect body weight control? This paper reviews evidence from laboratory, clinical and epidemiological studies in the context of current research on energy density, satiety and the control of food intake.

[Relationships between the "eating inventory" factors, socioeconomic status, anthropometric body adiposity indexes and health risks in Czech population]. / Vztahy mezi faktory "dotazniku jidelnich zvyklostí", socioekonomickým stavem, antropometrickými ukazateli akumulace tuku a zdravotnimi riziky u ceské populace.

BACKGROUND: The aim of the study was to compare and evaluate psychological traits of eating behaviour assessed using the Eating Inventory (El) known also as the Three Factor Eating Questionnaire (TFEQ) and their relationship to body adiposity, health and social characteristic in a quota sample of Czech adults. METHODS AND RESULTS: The sample included 1624 women and 1429 men who were interviewed individually by instructed investigators. The sample was quota representative--for gender, age, size of residential location, region and socioeconomic status in Czech adults. Anthropometric data were obtained together with socioeconomic and lifestyle information. Subjects filled out the EI. Health status was evaluated according to the data reported by GPs. Our results show, that women had higher restraint but lower disinhibition and hunger scores than men. Hunger and disinhibition were always strongly associated, whereas restraint was negatively related to the other two factors in men, and to hunger in women. In both men and women an educational level positively correlated with dietary restraint and negatively with hunger. However, significant negative relationship between educational level and disinhibition was revealed only in men. In backward stepwise regression analysis both dietary restraint and disinhibition predicted BMI and waist circumference. BMI and waist circumference were negatively related to restraint, but positively to disinhibition. Restraint and disinhibition were associated with prevalence of comorbidities in men, while disinhibition and hunger were in women. Individuals with high scoring in disinhibition score (upper quartile) exhibited significantly higher prevalence of hypertension, cardiovascular diseases and hyperlipidaemia than those who scored low (lower quartile). These relationships were most marked in middle-aged subjects. CONCLUSIONS: Psychological traits of eating behaviour seem to have an important role in the development and clinical expression of body adiposity. Especially disinhibition is significantly associated with BMI and waist circumference and prevalence of several pathologies.

Obesity, overweight and thinness in schoolchildren of the city of Florianópolis, Southern Brazil.

OBJECTIVE: To assess the prevalence of obesity, overweight (including obesity) and thinness in children of the city of Florianopolis (southern Brazil). DESIGN: Cross-sectional study. SUBJECTS: Representative sample of 7-10-y-old schoolchildren of the first four grades of elementary schools (1432 girls, 1504 boys). METHODS: Measurements of weight, height and triceps skinfold thickness (TSF) were taken following standard techniques. The body mass index (BMI) was computed as weight/height2. Nutritional status was defined using two references: (1) the Must et al reference for BMI and TSF to define thinness, overweight and obesity (5th, 85th and 95th percentiles, respectively); (2) the International Obesity Task Force (IOTF) BMI cutoffs to define overweight and obesity. RESULTS: Using BMI, according to the Must et al, and IOTF references, the prevalence of obesity was 10.6 and 5.5%, respectively; overweight (including obesity) affected 26.2 and 22.1% of children, respectively. According to the Must et al reference, the prevalence of thinness was 3.2%. Using TSF rather than BMI, according to the Must et al references, fewer children were classified as obese (8.0%) or overweight (20.2%) and more children were classified as thin (4.9%). CONCLUSION: This study supports the previously reported high frequencies of childhood overweight and obesity in developing countries. The data allow comparisons with other studies carried out in Brazil and other parts of the world.

Glutamate and the UMAMI taste: sensory, metabolic, nutritional and behavioural considerations. A review of the literature published in the last 10 years.

Monosodium glutamate (MSG) is used increasingly often in processed foods and in home cooking in the Western world. This substance is responsible for a pleasurable taste sensation, the Umami taste. This review covers recent developments in sensory studies of glutamate effects, and traces the Umami taste from sensory receptors on the tongue to the brain. The metabolism of glutamic acid, as revealed from recent literature, is described. A specific section is devoted to safety issues. In addition, effects of glutamic salts on nutrition and ingestive behaviours are shown to be potent. Animal and human works are treated separately, with special attention to the specific methods used in both cases. Future areas of research include further investigation of sensory physiology, role of glutamate as an excitatory substance in the brain, acquisition of food likes and impact on long-term food selection, food intake, and body weight control.

Low-energy substitutes for sugars and fats in the human diet: impact on nutritional regulation.

Low-calorie substitutes for dietary sugars and fats are offered to the public as aids in the control of body weight. Their actual influence on food intake and energy regulation has been studied in many acute and longer-term studies. Artificial sweeteners are often presented as preloads, and their effects on subsequent intake are compared to those of sugars or nonsweet vehicles. Preloads are often liquid (drinks) or semisolid (yogurts) and presented as snacks, rather than parts of a meal. Under these conditions, partial or complete compensation for the missing energy is observed most often over the course of a few hours. However, increases in appetite have also been reported. Low-energy fat substitutes also apparently allow energy, but not nutrient (fat) compensation. Short-term, medium-term, and long-term behavioural responses to the use of low-energy substitutes can be different, mainly as a result of learning. Consequently, effects of their chronic use on body weight, body composition, nutritional balance, and various physical parameters are only partially predictable on the basis of present knowledge. The present article reviews recent contributions to this field and delineate open areas of research.

Chewing and swallowing as indices of the stimulation to eat during meals in humans: effects revealed by the edogram method and video recordings.

Patterns of chewing and swallowing were recorded during standardized meals in humans. Cocktail size (3 cm2) open sandwiches were served in one of five different flavors. An oscillographic recording of chewing and swallowing showed that chewing activity varied with the palatability and variety of foods. Chewing time was shorter and fewer chews were observed as palatability increased. Swallowing did not change as a function of stimulus flavor. Pause duration between two successive food pieces became shorter as palatability increased. The effects of sensory factors were most evident at the beginning of meals and decreased until the end of meals. A later study which compared eating parameters in sandwich, semi-solid, and traditional French meals (different courses ingested in succession: appetizer, main course, cheese and dessert), as assessed from video recordings, found that different microstructure parameters responded to palatability manipulation in different meal types. Strength of mastication and prandial drinking might be other important parameters to look at in order to understand the motivation to eat and its fluctuations during the meal.

No correlation between adiposity and food intake: why are working class children fatter?

Many studies have failed to show a correlation between individual energy intake and obesity. However, the prevalence of overweight is higher in populations with higher caloric intake. In this study on a population of French children, no correlation was found between energy intake and individual corpulence (wt/ht2 index or skinfold thickness), but a higher proportion of overweight children was found in lower social classes where energy intake is traditionally higher. A hypothesis is proposed to account for this apparent contradiction: the typical lifestyle or diet in a given population challenges individual adaptive capacities; the more caloric the socially accepted diet, the higher the proportion of individuals who are challenged beyond their adaptive threshold. Socially determined factors such as a high calorie diet act in a permissive way in the development of obesity although the caloric intake of obese individuals may be no different from that of nonobese peers.

Cognitive restraint can be offset by distraction, leading to increased meal intake in women.

BACKGROUND: Cognitive restraint, a stable disposition to limit food intake, can be assessed by questionnaires, but there is no quantitative, objective measure of its effect. OBJECTIVE: The goal was to provide an objective measure of the intake-limiting effects of cognitive restraint by testing meal intake under conditions intended to minimize or accentuate restraint. DESIGN: Healthy women (n = 41; aged 35 +/- 9 y; body mass index, in kg/m2: 21.3 +/- 1.9) participated in once-weekly laboratory lunch tests under 4 conditions: condition 1, subjects ate alone (baseline); condition 2, subjects ate alone while listening to recorded instructions focusing on the sensory characteristics of the foods (attention); condition 3, subjects ate alone while listening to a recorded detective story (distraction); and condition 4, a group of 4 subjects had lunch together. On all occasions, the same foods were presented and ingested ad libitum. The Three-Factor Eating Questionnaire (TFEQ) was filled out after the series of 4 meals was completed. RESULTS: Meal size was significantly higher in the distraction condition than at baseline (by 301 +/- 26 kJ; P < 0.001). The difference in energy intake between the baseline and distraction conditions significantly correlated with factor 1 (cognitive restraint) of the TFEQ (r = 0.51, P < 0.01) and with total score (r = 0.32, P < 0.05) but not with disinhibition or hunger. For each additional point on factor 1, meal size increased by 50 kJ under the distraction condition compared with baseline. The group eating condition induced no increase in meal size. CONCLUSION: Cognitive restraint exerts a quantifiable limiting effect on intake at meal times and this effect can be offset by cognitive distraction.

Adiposity rebound in children: a simple indicator for predicting obesity.

To follow and predict the evolution of adiposity during growth, individual adiposity curves, assessed by the weight/height2 index, were drawn for 151 children from the age of 1 month to 16 yr. Adiposity increases during the 1st yr and then decreases. A renewed rise, termed here the adiposity rebound, occurs at about 6 yr. Individual weight/height2 curves may differ regarding their percentile range level and age at adiposity rebound. The present study shows a relationship between the age at adiposity rebound and final adiposity. An early rebound (before 5.5 yr) is followed by a significantly higher adiposity level than a later rebound (after 7 yr). This phenomenon is observed whatever the subject's adiposity at 1 yr. The present observations might be connected with the cellularity of adipose tissue.

Satiating effect of proteins in healthy subjects: a comparison of egg albumin, casein, gelatin, soy protein, pea protein, and wheat gluten.

The influence of six dietary protein types (egg albumin, casein, gelatin, soy protein, pea protein, and wheat gluten) on satiety and food intake was investigated. Twelve healthy subjects ingested six protein-manipulated lunches (approximately 5.2 MJ, 22% of energy as protein) according to a within-subjects design. Test meals were controlled for energy, macronutrients, fiber, and palatability. Nearly 65% of total protein varied between sessions. After lunch, satiety was assessed for 8 h and energy and macronutrients intakes were measured for 24 h. Blood was collected for determination of postprandial plasma glucose and insulin responses. Results showed no effect of the type of protein on satiety, on 24-h energy or macronutrient intakes, or on postprandial plasma glucose and insulin concentrations. These findings differ in part from those obtained previously in humans, which suggested that proteins may be differentiated in terms of their satiating capacities. We conclude that varying the protein source in a mixed meal does not affect food behavior in healthy humans, probably because coingestion of carbohydrate and fat with protein buffers the kinetics of the physiologic mechanisms implicated in postprandial satiety after a protein load.

Relationship between adiposity and food intake: an example of pseudo-contradictory results obtained in case-control versus between-populations studies.

Seemingly contradictory data support controversies concerning the relationships between food intake and illnesses. The present study of 1035 adults, aged 30-39 years, shows that (1) daily energy intake is not higher in obese than in non-obese people, (2) obesity is more prevalent in social groups where energy intake is higher. These pseudo-contradictory results can be reconciled on the basis of a constitution/environment interaction. A comparison of groups based on presence or absence of illness (obesity, hypertension, coronary heart disease (CHD), cancer, etc) shows that some people can develop risk factors, even though their feeding behaviour is normal. This result (no direct relationship) underlines differences in individual susceptibility. When comparisons are made between populations with different diets the results (direct relationship) express environmental factors. The hypotheses on behavioural contribution to the aetiology of certain diseases appears more clearly in between-population comparisons than in case-control studies. Results of comparisons between populations (if the hypotheses they suggest are confirmed by intervention studies) warrant prevention at the level of populations, while results of case-control studies justify particular prevention in subjects at risk.

Effects of monosodium glutamate on human food palatability.

Monosodium glutamate (MSG) is a well-known flavor enhancer used in both Western and Eastern cuisines. Responsible for the 'umami' (delicious) taste, it is incorporated into a large number of solid and liquid savory foods. Experimental studies have established that the presence of added MSG in foods influences palatability, preference and selection. Sensory evaluation tests have shown that both traditional and novel foods get higher palatability ratings if MSG is added at an appropriate dose. In young adults, behavioral tests have shown that the acquisition of a liking for novel foods is facilitated by the addition of MSG to the recipe. In institutionalized elderly persons as well as hospitalized diabetic patients, the addition of MSG to target foods in a lunch meal induced an increased intake for those specific foods, with a subsequent decreased intake of foods presented later in the meal. In both populations, only prandial food selection was affected by MSG, but meal size (kJoules) remained the same. Experiencing the positive effects of MSG is thus possible without inducing hyperphagia. In conclusion, MSG can be used casually by the consumer in order to increase palatability, and it can also be used selectively by nutrition experts in order to orient food selection toward a healthy diet composition.

Healthy dietary practices among European students.

Predictors of 5 healthy dietary habits were examined in data from the European Health and Behaviour Survey (A. Steptoe & J. Wardle, 1996), a study of over 16,000 students from 21 European countries. The level of practice of these healthy dietary habits was low. Significant univariate associations with healthy dietary habits were identified for gender, weight, dieting status, dietary health beliefs, nutrition knowledge, and health locus of control. In multivariate analyses, only gender, dieting status, and dietary health beliefs were significant predictors of healthy dietary habits. The practical implications of these results for dietary health promotion are discussed.