The eating behavior of obese and nonobese women

Sixty-one obese, normal weight and thin women were observed for 30 minutes as they consumed a free-choice lunch in a quasi-naturalistic setting. Their behavior was unobtrusively quantified in terms of microbehavior (mouthfulls, chews, drinks and pauses) and of the macrobehavior (type and amount of food consumed and total active eating or drinking time). Information on subject and environmental variables are also reported. Observed behavior was analyzed as comparative group totals and as patterns of behavior over time. Comparison of group totals showed that: (a) there were no differences in types of food or number of calories consumed between the three groups, (b) no differences were found between the eating behavior of the normal weight and the obese and (c) the obese women spent less time actively eating, less time chewing and more time drinking than did the thinnest group. Pattern analysis revealed a decrease in all responses over time but showed no significant pattern difference between groups.     

The influence of caloric information on cafeteria food choices

We evaluated the effect of posting caloric information on food purchases at a cafeteria. Purchases of more than 14,300 entrees, vegetables, and salads by 6,970 customers were unobtrusively monitored via the cash register inventory control system during 15 evening observations. A quasi-multiple-baseline design across food groups was used to test the additive effect of labeling the three lowest caloric choices for vegetables, salads, and entrees. A linear logit analysis confirmed that labeling increased the probability of low calorie selections for vegetables and salads, but not for entrees. Observations of meals purchased by a subsample of 413 customers indicated labeling did not change the total caloric content of meals. The number of customers and total sales per evening were unaffected by the labeling intervention. The results suggest that manipulating environmental cues may be an effective method for changing food purchases in a cafeteria, but labeling individual items may not be the best way to decrease total calories purchased.     

Effects of a short-term exercise program on caloric consumption

The present study investigated the effects of a short-term exercise program on caloric intake. Thirty-three women were randomly assigned to either a high-intensity exercise group (80% maximum heart rate), low-intensity exercise group (55% maximum heart rate), or waiting list control group. Exercisers were required to ride ergometer bicycles three times per week for 7 weeks, expending 200 kilocalories of energy per exercise session. All participants recorded food intake during specified weeks before, during, and following the exercise program. Results showed no significant caloric intake differences among the three groups, but a trend toward reduction in food intake with increased exercise intensity was found. Interestingly, comparisons between caloric intake on exercise and nonexercise days revealed that both exercise groups consumed significantly less on exercise days. Additionally, the control group evidenced a larger caloric intake level than did the two exercise groups on exercise days. These results suggest that exercisers do not compensate for energy expenditure by increasing caloric intake and that choosing between low- and high-intensity exercise does not differentially alter caloric intake. Nevertheless, maximization of negative energy balance or weight loss may be best achieved by exercise programs of high frequency and intensity.     

Self-regulatory Theory and Weight-Loss Maintenance

We examined the relationships between promotion and prevention focus and caloric consumption in reaction to a dietary lapse scenario among weight loss maintainers. Participants were 65 adult females who had attained and maintained a weight loss of 10 % or more for at least 1 month. After engaging in a dietary lapse in a feeding laboratory, participants completed a “bogus” taste test, during which they could consume as much food as they liked. It was hypothesized that promotion and prevention focus would predict caloric consumption, mediated by depressive and anxious affect. Prevention focus, but not promotion focus, was positively associated with proportion of daily calories consumed. Affect was not a mediator. Prevention focus may be deleterious for dietary maintenance following dietary lapses. Theoretical and clinical implications are discussed in light of prior research. Limitations of the study and recommendations for future research also are presented.     

Rats defend different body weights depending on palatability and accessibility of their food.

Normal adult rats lived on powdered diets adulterated to contain as much as 1.6% quinine sulfate, on a palatable high-fat diet, or in Skinner boxes with 45-mg Noyes pellets available on fixed-ratio (FR) schedules as high as FR 156. They maintained lower body weights over periods of months in proportion to the percentage of quinine adulteration or the fixed ratio. Rats exposed to the high-fat diet overate as much and gained weight as rapidly as rats recovering from food deprivation, and became moderately obese. Rats having become lean or obese contingent on the palatability or accessibility of their diet defended body weight by eating more in the cold, less when force-fed by gavage, and more to restore weight after food deprivation. Yet on chow they restored and defended body weights typical of rats whose diet had been confined to commercially prepared chow. These results are interpreted to be inconsistent with motivational models that rigidly distinguish drive from incentive, that treat body weight changes as evidence for failure to regulate energy balance or body weight, or that rely exclusively on deprivation of food or reduction of body weight for definitions of need for calories. Instead, caloric homeostasis in rats may incorporate ecological constraints.     

Caloric balancing and sucrose intake of hamsters and gerbils

In Experiment 1, hamsters and gerbils were randomly assigned to groups that were given a choice between pairs of sucrose solutions differing in concentration. The groups consisted of a control along with the following pairs: 2% and 6%; 2% and 8%; 2% and 12%; 2% and 18%; 6% and 8%; 6% and 12%; 6% and 18%; 12% and 18%. They were tested for 15 days, and the results indicated that the animals drank more from the cylinder containing the higher concentration. The principle of "least consummatory effort" appeared to be substantiated by these results. In Experiment 2, other hamsters and gerbils were randomly assigned to one of six groups receiving either 0.5%, 2%, 6%, 10%, 14%, or 18% sucrose solution. Analysis of their intake of sucrose and Purina Lab Chow indicated that their total caloric intake was relatively constant, reflecting the fact that an increase of consumption of the solutes in the sucrose solution reduced their intake of the stock diet. The results from both experiments indicated that although the caloric intake of hamsters relative to body weight was greater than that of gerbils, the proportion of total calories taken from sucrose was greater for the latter than for the former.     

No pain, no gain: Perceptions of calorie expenditures of exercise and daily activities

Reduction in physical activity is considered a major contributor to weight problems. Increasingly, people are expending less energy in household chores but joining fitness clubs. Do people perceive ordinary daily activities to expend less energy than exercise activities using similar amounts of calories? In the present study college students were asked to evaluate the calorie expenditure of 30 physical activities (i.e., exercises and household tasks). The household tasks were matched (in terms of caloric expenditure) to at least one exercise activity. When participants rated both exercise and daily activities, it appears that they focused on rate of caloric expenditure rather than type of activity (i.e., household task or exercise). In Study 2, college students evaluated the energy expenditure of light/leisure, moderate, and intense exercise. This emphasis concerning the benefit of intense physical activity was observed once again. College students appear to have assimilated the belief that intense physical activity expends more energy than longer sessions of lower intensity physical activity using similar amounts of calories. Perhaps one reason why people are not physically active is that they believe physical activities must be intense to be of benefit. At the same time they are automatizing household chores and, thus, become less active overall.     

No pain, no gain: Perceptions of calorie expenditures of exercise and daily activities

Reduction in physical activity is considered a major contributor to weight problems. Increasingly, people are expending less energy in household chores but joining fitness clubs. Do people perceive ordinary daily activities to expend less energy than exercise activities using similar amounts of calories? In the present study college students were asked to evaluate the calorie expenditure of 30 physical activities (i.e., exercises and household tasks). The household tasks were matched (in terms of caloric expenditure) to at least one exercise activity. When participants rated both exercise and daily activities, it appears that they focused on rate of caloric expenditure rather than type of activity (i.e., household task or exercise). In Study 2, college students evaluated the energy expenditure of light/leisure, moderate, and intense exercise. This emphasis concerning the benefit of intense physical activity was observed once again. College students appear to have assimilated the belief that intense physical activity expends more energy than longer sessions of lower intensity physical activity using similar amounts of calories. Perhaps one reason why people are not physically active is that they believe physical activities must be intense to be of benefit. At the same time they are automatizing household chores and, thus, become less active overall.     

Perceptions of women related to food choice

Male and female subjects (predominately white) provided impression ratings of body shape, personality traits, and total caloric consumption for a female target based on her preference for a low fat or high fat diet. Results showed that meal type significantly affected impression ratings: the target who preferred low fat foods was viewed more favorably than the one who preferred high fat fare. Compared with male subjects, female subjects perceived the target who preferred a high fat diet to be significantly less conscientious. Males were significantly more accurate than females in their caloric estimations of targets' total daily consumption. The results will be discussed in terms of the social pressure on women to restrict not only their weight to acceptable levels, but their food consumption as well.Portions of this paper were presented at the meeting of the Eastern Psychological Association, Providence, Rhode Island, April 14–17, 1994.The authors wish to thank Justina Bradley, Loraina Ghiraldi, and two anonymous reviewers for their thoughtful comments on an earlier version of this paper. Melissa Van Brocklin's help during the data collection was also greatly appreciated.     

Substitution and caloric regulation in a closed economy.

Three experiments were conducted to study the effect of an imperfect substitute for food on demand for food in a closed economy. In Experiments 1 and 2, rats pressed a lever for their entire daily food ration, and a fixed ratio of presses was required for each food pellet. In both experiments, the fixed ratio was held constant during a daily session but was increased between sessions. The fixed ratio was increased over a series of daily sessions once in the absence of concurrently available sucrose and again when sucrose pellets were freely available. For both series, increases in the fixed ratio reduced food intake, but body weight was reduced only in the no-sucrose condition. In the sucrose condition, body weight and total caloric intake (sucrose plus food) were relatively unaffected by increases in the fixed ratio. At all fixed ratios, food intake was proportionally reduced by the intake of sucrose. In Experiment 3, monkeys obtained food or saccharin by pressing keys; the fixed ratio of presses per food pellet was increased once when tap water was each monkey's only source of fluid, again when each monkey's water was sweetened with saccharin, and a third time when each monkey had concurrent access to the saccharin solution and plain water. Increases in the fixed ratio, but not the intake of the saccharin solution, reduced each monkey's food intake. Because neither rats' sucrose nor monkeys' saccharin intakes affected the slope of the respective demand curves for food, monkeys and rats increased their daily output of presses and thereby defended their daily intake of those complementary elements of food. However, sucrose reduced rats' food intake. The relative constancy of body weight and total caloric intake in the sucrose condition is consistent with the possibility that rats tended to regulate caloric intake.     

Impact of Group Settings and Gender on Meals Purchased by College Students

This study examines the impact of social context and perception of weight on calories purchased by college students in a natural setting. Not only did women in mixed‐gender groups purchase fewer calories than did women in same‐gender groups, but significant interaction effects exist among the gender composition of groups, perception of being overweight, and gender of respondents. Men modified calories purchased across mixed‐gender and same‐gender groups, purchasing more when in mixed‐gender groups. The study helps address theoretical and methodological gaps in prior research and frames the findings in terms of variation of gender salience across social relational contexts.     

Elimination of reinforced behavior: intermittent schedules of not-responding

Pigeons' key pecking resulted in food according to either a variable-ratio or a variable-interval schedule. At the same time, food was available for not pecking for a specified time. The required time of not-pecking was segmented into not-responding units, and these units were followed by food according to a fixed-ratio schedule. Both unit duration and the number required were varied. In general, the shorter the time unit or the smaller the ratio, the lower was response rate. When total required not-responding time was constant, but changes in unit duration and the number required altered how the total was achieved, shorter units produced lower rates. Other conditions involved substitution of food delivered independent of responding for the not-responding schedule. With low and moderate total times to food presentation, the not-responding schedule produced lower rates; with the longest times, the response-independent schedule generated less responding. When considered in terms of relative frequency of food presentation available from a source other than pecking, the not-responding schedule reduced rate more effectively than did the response-independent schedule. Comparisons with other research suggested that food presented dependent on not responding compared favorably with punishment as a procedure for reducing response rate. Transient effects differed. Although punishment temporarily depresses rate when first imposed and temporarily enhances it when first removed, food given for not responding quickly generated steady-state rates.     

Changes in feeding and foraging patterns as an antipredator defensive strategy: a laboratory simulation using aversive stimulation in a closed economy.

The effects of the risk of electric shock on the meal patterns of rats living in an operant chamber were investigated. Rats could obtain food by working on a response lever that provided reinforcement according to chained fixed-ratio continuous reinforcement schedules that allowed the animals control over meal size. Using a two-compartment operant chamber with a safe nesting area and manipulanda area with a grid floor, shock could be correlated with responding on the schedule. Shocks (less than or equal to 1.25 per hour) were scheduled to occur randomly throughout the day, independent of the rat's behavior. Shock caused a reorganization of meal patterns such that the animals took less frequent but larger meals. This pattern reduced the time the animals spent at risk without compromising caloric balance. Similar changes in feeding pattern were obtained in both hooded and albino rats. Exposure to shock in a separate chamber did not produce these behavioral modifications. The magnitude of shock-induced alterations of meal patterns was greater with chained fixed-ratio 90 continuous reinforcement than with chained fixed-ratio 10 continuous reinforcement. Additionally, the rats seemed to be able to reduce food intake but increase caloric efficiency, such that the reduced food intake did not have deleterious effects on maintenance of body weight. These behavioral modifications reduced the number of shocks received from that which would have been expected if meal pattern changes had not occurred. We suggest that this technique may provide a useful laboratory simulation of the impact that the risk of predation has on foraging behavior.     

EFFECTS OF CALORIC LEVEL ON RUMINATING

A series of recent studies has shown that a number of dietary variables affect ruminative behavior in institutionalized retarded persons. This experiment extends an earlier study that examined the influence of the caloric level of the diet on the frequency of ruminating. Subjects consumed regular portions of food that varied between phases from normal to high caloric levels. The data show a clear but modest inverse relation between the caloric value of the diet and the rates of postmeal ruminating.     

Content Hungry: How the Nutrition of Food Media Influences Social Media Engagement

What motivates people to consume and engage with food media on social networks? We adopt an evolutionary lens to suggest that the valence of people’s affective state varies by the implied caloric density of food media, which has a direct impact on social media engagement. First, we analyze a catalog of Buzzfeed’s Tasty videos based on nutritional content derived from the dish’s ingredients and find that visualizing caloric density (i.e., calories per serving) positively influences likes, comments, and shares on Facebook. We then replicate this phenomenon in an experiment, providing preliminary evidence for the role of affect as an explanatory mechanism. We conclude by isolating the role of affect with a classic misattribution task, which attenuates the elevated engagement resulting from exposure to calorie-dense food media. These findings contribute to the dialogue on the antecedents of social media engagement and offer implications for content developers, advertisers, consumer health advocates, and policymakers.     

Autoshaping: further study of "negative automaintenance"

The key pecking of pigeons was autoshaped to three key colors paired with food in discrete trials. Then, the effects of three different color-correlated contingencies were compared: reward (presentation of food contingent on pecking), omission (presentation of food prevented by pecking), and extinction (no food). Two measures of performance were used: initial response (the number of trials with each color on which at least one peck was made) and multiple response (the total number of pecks per trial). In general, the reward color produced more pecking than the omission color, the omission color more than the extinction color, and the extinction color more than on blank trials with an unlighted key, although (relative to reward) omission produced a higher level of initial than of multiple responding. These results point clearly to the importance of stimulus-reinforcer continguity in the control of pecking.     

Effects of nutritional and mechanical properties of food on ruminative behavior.

Previous studies have identified a reliable relation between the quantity of food ingested and ruminating in profoundly retarded individuals and have established some parametric characteristics of this relation. The present study investigated three different properties of food that may influence this relation. Experiment 1 examined the role of stomach distention produced by including in the subject's diet wheat bran in amounts equivalent to and exceeding the calculated amount of crude fiber in the starch-satiation diet reported by Rast, Johnston, Drum, and Conrin (1981) and Rast, Johnston, and Drum (1984). There was a decrease in ruminating, although this decrease was smaller and more gradual than in the starch-satiation condition. Experiment 2 showed that increasing calories without increasing food volume resulted in a gradual and moderate decrease in ruminating. Experiment 3 replicated and extended the first two experiments by varying both caloric intake and stomach distention as well as oropharyngeal and esophageal stimulation in a different sequence of conditions. All variables exerted some control over responding. However, the large and immediate effects of the starch-satiation procedure occurred only when subjects were permitted to consume unlimited quantities.     

Restrained eating: an experimental disentanglement of the disinhibiting variables of perceived calories and food type

The influence of food type on the restrained eating pattern was examined. In Study 1, subjects rated the degree to which each of 149 foods were dietary permissable or dietary forbidden. The number of avoided foods correlated positively with restraint score. Study 2 compared Herman and Mack's (1975) 1- and 2-milk shake preloads to two nonforbidden preloads of equivalent calories. Food type, and not perceived calories, was found to be the element of the preload required to cause disinhibition among restrained eaters, both within the experiment and outside the experimental setting. Study 3 examined the effects of anticipated consumption (varying food type and calories) on the restrained eating pattern. Only restrained eaters anticipating a forbidden food (whether high or low in calories) were disinhibited. The restrained literature was reconsidered in light of the forbidden food hypothesis.     

A comparison of the validity of three scales for the assessment of dietary restraint

The construct validity of Herman and Polivy's Restraint Scale (RS), the restraint factor of the Three Factor Eating Questionnaire (TFEQ-R), and the restraint scale of the Dutch Eating Behavior Questionnaire (DEBQ-R) were investigated by relating these scales to self-reported mean caloric intake per day and to other measures associated with disordered eating and figure consciousness. A factor analysis showed that the three restraint scales measure different components of the restraint construct. A high score on the RS was closely related to consequences of mostly unsuccessful dieting, such as disinhibited eating and weight fluctuations, but not to successful overall caloric restriction in everyday life. High scores on the TFEQ-R and the DEBQ-R represented the more successful dieting behavior component of restraint. The three scales have in common a motivational component of restrained eating, including concerns about shape and weight, and desire for thinness.     

Scarce Foods are Perceived as Having More Calories

People vary dramatically in their calorie estimates of food depending on the information available to them. Prior research has focused on information that is normatively relevant to the number of calories a food contains (e.g., fat content, serving size). The current research examines whether information that is normatively irrelevant to the number of calories a food contains—such as its availability—might also shape people's calorie estimates. Three studies found that a food perceived as limited in availability leads people to estimate the food to contain more calories. Serial mediation analyses revealed that this effect occurs because scarce food is seen as more valuable and expensive, which subsequently induces feelings of resource deprivation. This sense of resource deprivation, in turn, leads to motivated perception, whereby higher calorie estimates are the result of people wanting to acquire more resources. The findings provide insight into the psychology of scarcity and underscore the importance of understanding how contextual factors shape people's calorie estimates and the psychological mechanisms that drive them.