Sensory-specific satiety: comparison of taste and texture effects

The respective contributions of taste (saltiness and sweetness) and texture (the hardness dimension) to sensory-specific satiety (SSS) were compared. Sixteen male and 16 female, young, normal-weight adults rated the pleasantness of taste, pleasantness of texture and desire to eat on visual analog scales for eight test foods, were then given one of the foods to eat ad libitum for lunch, and re-rated the same parameters for the eight foods 2 and 20 min after the end of the meal. The experimental sets of eight test foods and four lunch foods were balanced for taste quality (salty vs. sweet) and texture quality (hard vs. soft). Lunch foods were the hard and soft versions of a salty food (ham and cheese sandwich on baguette vs. white bread) or of a sweet food (apples vs. applesauce). Sensory-specific satiety was observed for both saltiness and sweetness (e.g. pleasantness of the taste of, and desire to eat sweet test foods decreased significantly after eating a sweet lunch food and similarly for salty foods), and to a lesser extent for texture (e.g. pleasantness of the texture of, and desire to eat hard test foods decreased after eating a hard lunch food and similarly for one of the soft foods). The authors conclude texture-specific satiety may be a significant component of satiety.     

Selective effects of naltrexone on food pleasantness and intake

The effects of 50 mg naltrexone on both pleasantness and intake of 10 common food items were investigated using a double-blind placebo-controlled study with 16 male volunteers. Rated food pleasantness was reduced significantly in the naltrexone condition compared with both controls (placebo and baseline). However, pleasantness ratings were not affected uniformly across foods, with sweetened, fatty, and high-protein foods being most affected. Changes in rated unpleasantness generally mirrored those for pleasantness, but evaluations of saltiness and sweetness were unaffected by naltrexone. Although total intake was reduced in the naltrexone condition, this was not significant compared with placebo. However, fat and protein intakes were significantly less following naltrexone. The effect of naltrexone on intake was also food dependent, but in this case intake of sweet foods was spared relative to other food categories. The apparent discrepancy between liking and intake data with sweet foods could be interpreted in terms of the likely influence of normal eating styles on food selection during a buffet-style meal, and may explain some contradictions in previous studies of this kind. The implications for understanding opioid involvement in food acceptability are discussed.     

Color as a factor in food choice

From birth, nature teaches us to make judgements on our environment based in large measure on color. As such, it plays a key role in food choice by influencing taste thresholds, sweetness perception, food preference, pleasantness, and acceptability. Its role is elusive and difficult to quantify, however, which at times has placed color in a secondary role to the other sensory characteristics, a position not entirely consistent with the facts. Color, in a quantitative sense, has been shown to be able to replace sugar and still maintain sweetness perception in flavored foods. It interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods. Studies in the literature have used cross-sectional population panels to study these effects, but a recent investigation of color-sensory interactions in beverages has compared the response of a college age group with the response of a panel consisting of a more mature population. Interestingly, the older group showed significant differences from the college age group in their response to the effects of color on several sensory parameters as well as showing a direct correlation between beverage consumption and color. Color is often taken for granted, but this position must be reevaluated in view of such studies and the need to create more appealing foods for different segments of our society.     

Responses to the sensory properties of fat of neurons in the primate orbitofrontal cortex

The primate orbitofrontal cortex is a site of convergence of information from primary taste, olfactory, and somatosensory cortical areas. We describe the responses of a population of single neurons in the orbitofrontal cortex that responds to fat in the mouth. The neurons respond, when fatty foods are being eaten, to pure fat such as glyceryl trioleate and also to substances with a similar texture but different chemical composition such as paraffin oil (hydrocarbon) and silicone oil [Si(CH3)2O)n]. This is evidence that the neurons respond to the oral texture of fat, sensed by the somatosensory system. Some of the population of neurons respond unimodally to the texture of fat. Other single neurons show convergence of taste inputs, and others of olfactory inputs, onto single neurons that respond to fat. For example, neurons were found that responded to the mouth feel of fat and the taste of monosodium glutamate (both found in milk), or to the mouth feel of fat and to odor. Feeding to satiety reduces the responses of these neurons to the fatty food eaten, but the neurons still respond to some other foods that have not been fed to satiety. Thus sensory-specific satiety for fat is represented in the responses of single neurons in the primate orbitofrontal cortex. Fat is an important constituent of food that affects its palatability and nutritional effects. The findings described provide evidence that the reward value (or pleasantness) of the mouth feel of fat is represented in the primate orbitofrontal cortex and that the representation is relevant to appetite.     

Family health care delivery for the 21st century

The objective of this study was to investigate whether and how parotid saliva flow and composition correlated with the perception of gustatory and/or trigeminal stimuli in foods. Thirty (15 male and 15 female) subjects tasted seven foods or beverages (lemonade, beer, wine, soup, methyl cellulose, peanut butter, and crackers) with three levels each of a gustatory or trigeminal stimulus and rated the perceived intensity of the corresponding sensation over time using the time-intensity (TI) method while their parotid saliva was being collected. Salivary flow rates of males were significantly higher than those of females for all stimuli (p < 0.001). That did not translate, however, into consistent differences in perception of sensory attributes between males and females. Significant positive correlations were found between saliva flow and (1) TI parameters for adhesiveness of peanut butter and cohesiveness of mass of crackers (p < 0.05 or lower) and (2) time from intake to swallowing of crackers and peanut butter (p < 0.05). No correlations were found between saliva composition (e.g., sodium and total protein) and TI parameters. These results indicate that parotid saliva flow may correlate with the perception of some texture and mouthfeel attributes (presumably through oral work and bolus formation) but not with that of the taste attributes examined in this study (at the concentrations studied).     

Acquired aversions as the basis for varied diets of ruminants foraging on rangelands

Ruminants eat an array of plant species that vary in nutrients and toxins. This selection makes intuitive sense, but no theories adequately explain this diversity. Some maintain it reduces the likelihood of overingesting toxins, whereas others contend it meets nutritional needs. Nevertheless, herbivores seek variety even when toxins are not a concern and nutritional needs are met. I offer another explanation for this behavior, one which encompasses the avoidance of toxins and the acquisition of nutrients. A key concept in this theory is aversion, the decrease in preference for food just eaten as a result of sensory input (a food's taste, odor, texture, i.e., its flavor) and postingestive effects (effects of nutrients and toxins on chemo-, osmo-, and mechano-receptors) unique to each food. Aversions are pronounced when foods contain toxins or high levels of rapidly digestible nutrients; they also occur when foods are deficient in specific nutrients. Aversions occur even when animals eat nutritionally adequate foods because satiety (satisfied to the full) and surfeit (filled to nauseating excess) represent points along a continuum, and there is a fine line between satiety and aversion. Thus, eating any food is likely to cause a mild aversion, and eating a food too frequently or in excess is likely to cause a strong aversion. Aversions are involuntary and are not the result of conscious decisions by an animal. Aversions yield benefits (e.g., obtain a balanced diet, reduce ingestion of toxic foods, optimize foraging and rumination times, sample foods, maintain a diverse microflora in the rumen) that are often mistaken as the cause of varied diets. In this article, I discuss the subtle ways in which aversions diminish preference and cause animals to eat a variety of foods.     

A role for sweet taste: Calorie predictive relations in energy regulation by rats.

Animals may use sweet taste to predict the caloric contents of food. Eating sweet noncaloric substances may degrade this predictive relationship, leading to positive energy balance through increased food intake and/or diminished energy expenditure. These experiments were designed to test the hypothesis that experiences that reduce the validity of sweet taste as a predictor of the caloric or nutritive consequences of eating may contribute to deficits in the regulation of energy by reducing the ability of sweet-tasting foods that contain calories to evoke physiological responses that underlie tight regulation. Adult male Sprague-Dawley rats were given differential experience with a sweet taste that either predicted increased caloric content (glucose) or did not predict increased calories (saccharin). We found that reducing the correlation between sweet taste and the caloric content of foods using artificial sweeteners in rats resulted in increased caloric intake, increased body weight, and increased adiposity, as well as diminished caloric compensation and blunted thermic responses to sweet-tasting diets. These results suggest that consumption of products containing artificial sweeteners may lead to increased body weight and obesity by interfering with fundamental homeostatic, physiological processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why Americans eat what they do: taste, nutrition, cost, convenience, and weight control concerns as influences on food consumption

OBJECTIVE: To examine the self-reported importance of taste, nutrition, cost, convenience, and weight control on personal dietary choices and whether these factors vary across demographic groups, are associated with lifestyle choices related to health (termed health lifestyle), and actually predict eating behavior. DESIGN: Data are based on responses to 2 self-administered cross-sectional surveys. The main outcomes measured were consumption of fruits and vegetables, fast foods, cheese, and breakfast cereals, which were determined on the basis of responses to questions about usual and recent consumption and a food diary. SUBJECTS/SETTING: Respondents were a national sample of 2,967 adults. Response rates were 71% to the first survey and 77% to the second survey (which was sent to people who completed the first survey). STATISTICAL ANALYSES: Univariate analyses were used to describe importance ratings, bivariate analyses (correlations and t tests) were used to examine demographic and lifestyle differences on importance measures, and multivariate analyses (general linear models) were used to predict lifestyle cluster membership and food consumption. RESULTS: Respondents reported that taste is the most important influence on their food choices, followed by cost. Demographic and health lifestyle differences were evident across all 5 importance measures. The importance of nutrition and the importance of weight control were predicted best by subject's membership in a particular health lifestyle cluster. When eating behaviors were examined, demographic measures and membership in a health lifestyle cluster predicted consumption of fruits and vegetables, fast foods, cheese, and breakfast cereal. The importance placed on taste, nutrition, cost, convenience, and weight control also predicted types of foods consumed. APPLICATIONS: Our results suggest that nutritional concerns, per sc, are of less relevance to most people than taste and cost. One implication is that nutrition education programs should attempt to design and promote nutritious diets as being tasty and inexpensive.     

Food preferences in Prader-Willi syndrome, normal weight and obese controls

OBJECTIVE: The aim of this work was to assess the specific food type (high carbohydrate, high fat, high protein) preference profiles of individuals with Prader-Willi syndrome (PWS), obese controls and normal weight individuals. DESIGN: Subjects tasted a food predominantly high in carbohydrate, a food predominantly high in protein and a food predominantly high in fat over repeated trials and indicated their most preferred, second preferred and least preferred foods. Specific items tested on a given trial were counterbalanced in a block randomized fashion. SUBJECTS: These were 12 individuals with Prader-Willi syndrome, 12 matched obese controls (obese, but otherwise normal) and 14 normal weight subjects. MEASUREMENTS: The basic data were expressed as a proportion of each food type selected as most preferred over the total 27 trials. RESULTS: PWS subjects preferred high carbohydrate foods over high protein foods and high protein foods over high fat foods. These subjects demonstrated a statistically reliable difference in preference for high carbohydrate foods over high fat foods. However, normal weight and obese control subjects demonstrated no difference in food preferences. The only significant between-group comparisons were between PWS subjects and obese controls, with the PWS group showing a significantly greater preference for high carbohydrate foods than obese controls. CONCLUSIONS: The obesity of PWS was shown to have a significant and distinctly different food preference profile from normal weight and obese controls. The differences in food preference between the obese PWS and non-PWS subjects is in accord with the growing recognition of functional subgroups within the obese population, that may have not only differing underlying etiologies, but also distinct behavioral profiles of ingestion.     

Class differences in the food rules mothers impose on their children: a cross-national study

Many studies indicate that children in middle-class families have healthier eating habits than children in lower class families. Class differences in food rules, which parents and especially mothers impose on their children, may underlie these social inequalities in food consumption. The present study uses education as a classifying variable and analyses whether mothers with higher education prescribe more "healthy" foodstuffs for their children and whether they restrict more "unhealthy" food items than less educated mothers. Moreover, the study examines whether higher class mothers consider health aspects more often and the preferences of their family members less often in their choice of food, and whether class differences in these considerations explain class differences in food rules. To answer these questions, questionnaires on the food practices of 849 women living in middle-class or lower class districts in Maastricht (the Netherlands), Liège (Belgium) and Aachen (Germany) were collected and analysed. The majority of mothers in each city prescribed primarily foods that were served at dinner like meat and vegetables, and most mothers limited their children's consumption of sweet foods, soft drinks and snacks. Higher class mothers restricted more foods, but prescribed as many food items as their lower class counterparts. Class differences in the number of restricted foods were partly, but not completely, explained by class differences in health and taste considerations. Despite national variations in dietary habits and possibly in the education of children, class differences in food rules and the explanatory power of health and taste considerations were comparable in the three cities.     

Effects of anxiety on eating: Does palatability moderate distress-induced overeating in dieters?

When confronted with an anxiety-producing threat to self-esteem, restrained eaters (dieters) increase their food consumption. The functional explanation suggests that increased eating temporarily counteracts or masks dysphoria for the restrained eater; externality or stimulus sensitivity theories propose that distress shifts the dieter's attention to external stimulus properties (e.g., taste) and to activities stimulated by such external cues. In an attempt to distinguish between these two explanations, anxious and nonanxious restrained and unrestrained eaters were given palatable and unpalatable foods, and consumption was measured. Results support the functional explanations: Distressed dieters increased their intake of food regardless of taste properties. Theoretical and practical implications for both restrained eating and the behavior of eating disorder patients are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing yourself as an emotional eater: Mission impossible?

Objective: The extent to which individuals are emotional eaters has typically been assessed by people’s self-reported desire to eat when they experience negative emotions. Elevated scores on these emotional eater scales have been associated with eating pathology and obesity. However, evidence that individuals scoring high on these scales truly increase their food intake during emotional encounters is inconclusive. The current studies tested whether emotional eater scales capture the proposed tendency to eat when feeling emotional. Design: In four experiments with different emotion induction procedures, female participants were randomly assigned to negative emotion or control conditions. In the control conditions positive or no emotions were induced. Next, food consumption was assessed by bogus taste tests. Main Outcome Measures: Emotional eater status, emotional experience, and actual consumption of different food types. Results: Individuals describing themselves as emotional eaters did not increase food intake during emotional encounters as compared to control conditions or individuals not judging themselves as emotional eaters. Conclusion: The results suggest that self-reported emotional eaters do not increase food intake during emotional encounters in the laboratory. Implications of these findings are discussed, including the idea that it may be complex to adequately assess one’s own emotional eating behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Volatile flavor release from foods during eating

Classical analyses for volatile flavors (headspace or distillation/extract methods) give information on either the volatiles present in the air above a food before eating or the total volatile composition of the food. When foods are eaten, however, many changes take place (such as hydration/dilution with saliva, increase in surface area, etc.) that affect the release of volatiles from the food and therefore the profile of volatiles that are sensed in the nose. If we wish to study the relationship between flavor volatiles and the sensory properties of a food, it seems logical to measure the volatile profile that exists during eating. Although volatile flavor release during eating has been measured using a variety of sensory and psychophysiological analyses, only recently have instrumental methods been developed to measure the release of volatile compounds in humans as they eat. Whereas the sensory data give an overall measure of flavor perception, instrumental analyses can potentially follow the release of each and every flavor volatile and thus give a full picture of the aroma profiles generated during eating. From these instrumental measurements, a number of key factors have been identified. First, it has been shown that the volatile profile measured during eating is indeed different from the headspace profile of whole foods. Second, it is clear that the volatile profile in-mouth changes with time as the state of the food changes with chewing. Third, the volatile release from low-water foods is affected by the rate and extent of hydration in-mouth. The ability to measure aroma before, during, and after eating may lead to an understanding of the links between aroma release, interaction of volatiles with aroma sensors in the nose, and the overall perception of food flavor.     

Examining the addictive-like properties of binge eating using an animal model of sugar dependence.

The increase in the incidence of obesity and eating disorders has encouraged research efforts aimed at understanding the etiology of abnormal eating behaviors. Clinical reports have led to the suggestion that some individuals may develop addictive-like behaviors when consuming palatable foods. Binge eating is a behavioral component of bulimia and obesity and has also become increasingly common in nonclinical populations in our society. This review summarizes the behavioral and neurochemical similarities between binge eating of palatable foods and the administration of drugs of abuse. An animal model of bingeing on sugar is used to illustrate behaviors found with some drugs of abuse, such as opiate-like withdrawal signs, enhanced intake following abstinence, and cross-sensitization. Related neurochemical changes commonly observed with drugs of abuse, including changes in dopamine and acetylcholine release in the nucleus accumbens, can also be found with bingeing on sugar. These neurochemical alterations are exacerbated when animals binge on sugar while at a low body weight or when the food they ingest is purged. Drawing on other animal models and the clinical literature, parallels between drug abuse and binge-eating behavior are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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.     

Priming effects of television food advertising on eating behavior.

Objective: Health advocates have focused on the prevalence of advertising for calorie-dense low-nutrient foods as a significant contributor to the obesity epidemic. This research tests the hypothesis that exposure to food advertising during TV viewing may also contribute to obesity by triggering automatic snacking of available food. Design: In Experiments 1a and 1b, elementary-school-age children watched a cartoon that contained either food advertising or advertising for other products and received a snack while watching. In Experiment 2, adults watched a TV program that included food advertising that promoted snacking and/or fun product benefits, food advertising that promoted nutrition benefits, or no food advertising. The adults then tasted and evaluated a range of healthy to unhealthy snack foods in an apparently separate experiment. Main Outcome Measures: Amount of snack foods consumed during and after advertising exposure. Results: Children consumed 45% more when exposed to food advertising. Adults consumed more of both healthy and unhealthy snack foods following exposure to snack food advertising compared to the other conditions. In both experiments, food advertising increased consumption of products not in the presented advertisements, and these effects were not related to reported hunger or other conscious influences. Conclusion: These experiments demonstrate the power of food advertising to prime automatic eating behaviors and thus influence far more than brand preference alone. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Food preferences, eating patterns, and physical activity among adolescents: correlates of eating disorders symptoms

PURPOSE: Food preferences, eating patterns, and physical activity patterns were examined in a cohort of adolescent females and males participating in a longitudinal study of the developmental antecedents of eating disorders. METHODS: All adolescents (n = 1494) in grades seven through ten in an entire school district completed a survey about their dieting behaviors, eating, and exercise patterns. RESULTS: Principal components analysis showed similar factor structures for food preferences and eating patterns among males and females. Gender differences were present in physical activity patterns. Sports participation was correlated with healthy food preference and was a significant predictor of eating disorders symptoms. Junk food preference was marginally inversely related to eating disorders symptoms in females. Preference for other types of foods and reported intake of foods were not related to eating disorders symptoms. The percent of variance in risk score accounted for by dietary intake and physical activity patterns was small. CONCLUSIONS: Psychological and social/environmental variables may explain a larger proportion of the variance in eating disorders risk than the dietary and physical activity variables examined in this study. Implications for understanding the etiology and behavioral expression of eating disorders are discussed.     

Sources of bias in a dietary survey of children

OBJECTIVE: To compare non-responders and responders to a dietary survey with respect to demographic variables and intention to choose selected breakfast foods, and to examine if there was any systematic change in number of food items reported during a 7 d recording period. DESIGN: Cross-sectional survey. SETTING: M?lndal, Sweden. SUBJECTS: All pupils in 5th, 7th and 9th grades in the municipality were asked to complete a questionnaire during school hours. All those present (n = 1584, 92% of total) answered questions about lifestyle factors and about intentions, attitudes and beliefs concerning high-fibre bread and milk with varying fat content. All subjects in the initial sample were asked to fill in a 7 d record of food consumed. Acceptable food records were completed by 69% of the initial participants. RESULTS: Subjects not completing the food record differed significantly from participants with respect to demographic, lifestyle and dietary factors. Dropout was more common among those who reported not usually eating breakfast and among those intending to drink whole milk for breakfast. A decline in reported food items during the recording period was also observed. CONCLUSIONS: Two sources of bias were observed here, one indicating significant differences between non-participants and participants, the other suggesting the presence of a time-dependent trend in number of recorded foods. It is likely such biases are present in other dietary surveys involving schoolchildren, and should be taken into consideration in the design, analysis and interpretation of such studies.     

The effect of dietary fiber supplementation in man. I. Modification of eating habits

Six subjects were studied for an 8-week period that consisted of a 3-week control period, followed by a 3-week period during which their daily diets were supplemented with 3 oz of a high fiber breakfast food, All-bran, and a final 2 weeks on their regular diet. Daily diet records of food intake were recorded and analyzed for seven dietary constituents; carbohydrates, proteins, fats, cholesterol, fiber, alcohol, and total calories. The most significant change in eating behavior due to the fiber food supplementation was a decrease in eating eggs, butter, and breakfast meats. These foods were most often replaced because all six subjects chose to eat the major portion of All-bran during breakfast. An increase in milk and fruit also occurred during the supplemented feeding. These particular foods were added to make All-bran more palatable and served to increase carbohydrate and protein intake. Five subjects added the supplement to the between meal-time intake and thus caused an increase in total daily caloric intake. At lunch and dinner few foods were altered with no particular pattern of substitution. Notwithstanding the knowledge that increased fiber content may have beneficial effects, none of the subjects modified his eating behavior to include even 1 oz of a high fiber food daily after the experimental period was concluded. Thus behavior modification by forced diet intake of a high fiber breakfast food resulted in definite diet pattern changes that did not persist following the experimental period.     

Ultraviolet inactivation of the midi variant of Qbeta-RNA. Determination of quantum yield and lesions produced

The Chinese restaurant syndrome consists of a characteristic symptom complex, with limited times of onset and duration after eating in a Chinese restaurant. There is widespread belief that the C.R.S. is due to monosodium glutamate used in preparing food in Chinese restaurants and that as many as 25 per cent of the general population may be susceptible to the syndrome. Questionnaires were developed to determine the unpleasant symptoms which 530 subjects associated with specific foods, eating places, and "ethnic" styles of preparing food. Over 90 per cent of respondents associated unpleasant symptoms with specific foods, but only 6.6 per cent experienced an event which would "possibly" represent the characteristic C.R.S. Nevertheless, when the phrase "Chinese restaurant syndrome" was introduced in a second questionnaire, 31 per cent of respondents believed that they were personally susceptible to it. Many people do experience unpleasant symptoms after eating, and particularly after eating food associated with a different culture. Although the responses to food symptomatology questionnaires represent an important aspect of the sociology of eating behavior, this procedure should not be considered an objective data collecting system.