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Duration of Anticipated Deprivation and Its Effects on Food Intake in Restrained Eaters:
A Pilot Study

By: Bianca A. Reyes


Abstract
Method
Discussion
References Relevant Links
Introduction
Results
Acknowledgements



Abstract

This study was designed to examine the effects of anticipated deprivation on food intake in restrained eaters.  Research has shown that the mere plan of going on a diet can trigger overeating in restrained eaters (Urbszat, Herman, & Polivy, 2002).  The current study further explores this proposal by examining whether the extent of disinhibited eating is proportional to the length of the anticipated diet.  A follow up study was also done to investigate the effects of anticipated deprivation on food preference in restrained and unrestrained eaters.


Introduction


In response to health concerns and cultural pressures, dieting behavior has increased steadily in the United States over the past 40 years (Friedman, Shwartz, & Brownell, 1998).  With new Fad diets being introduced to the public on what seems like a daily basis, it is no wonder that this phenomenon has become a growing topic of interest in the scientific community.  Specifically, researchers have been interested in understanding the psychological consequences of such weight fluctuations over time. 
Many studies have focused on the disinhibition of suppressed or restrained eating in clinically normal dieters.  Even in a laboratory setting, dieters have consistently exhibited what has been called counter-regulation—a pattern in which they eat little amounts of food after no preload or a small forced preload (thus maintaining their diets), but eat a great deal of food after being forced to consume large, high calorie preloads (Herman & Mack, 1975; Herman, Polivy, & Silver, 1979; Polivy, 1976; Ruderman & Wilson, 1979; Spencer & Fremouw, 1979).Non-dieters, by contrast, exhibit normal regulation in that they eat much more food after no preload or a small forced preload than after a large preload.  It seems that , for the dieters, the high-calorie forced preload  triggers the overeating by ruining the diet temporarily and unleashing the sort of vigorous eating that is chronically restrained in the dieter.
Another theory that has been generated by researchers interested in restrained eating, is known as anticipated deprivation.  If instead of the mere absence of a preload, circumstances dictate a significant deprivation on future food intake, the paradoxical effect of stimulating overeating in the present is theorized to occur. 
A study done by Urbszat, Herman, & Polivy (2002) tested whether anticipated deprivation—independent of anticipated dietary violation—can lead to overeating in restrained eaters.  The hypothesis that restrained eaters that believed they would be going on a weeklong restrictive diet would abandon their dietary restraint and consume more food than would restrained eaters not anticipating a diet, proved to be true.
The current study further explores the findings of Urbszat, Herman, & Polivy (2002), by investigating the duration of anticipated deprivation and its effects on food intake in restrained eaters.


Method

Study 1:

Participants
   
Sixty-eight female undergraduate students from Saint Anselm College were recruited as participants for this study.  The subjects were a mixture of student volunteers, as well as Introduction Psychology students who received extra credit for their participation.  Participants were all females and ranged in age from 18-22. 

Materials
  
 Instruments were administered to the participants regarding the nature and purpose of the study.  A consent form was also distributed detailing the rights of the participants (See Appendix A).  In addition, an intake demographic questionnaire was completed which obtained information regarding the subject’s height, weight, year in college, major, ethnic background, past and present dieting history, as well as their current level of physical activity.  Participants were also asked whether they had ever been diagnosed with an eating disorder (See Appendix B).
    The Restraint Scale (Herman & Polivy, 1980) is a tool used to identify retrained eaters, or those individuals who attempt to restrict their intake of food in general, and/or of “fattening” food in particular, but who are vulnerable to various factors that disrupt such restriction.  There are questions on the Restraint Scale that assess or presuppose a susceptibility to engage in disinhibited eating, or binge-like eating (Appendix C).  On the basis of previous research and for the purposes of this study, those individuals scoring 15 or higher on the Restraint Scale were classified as restrained eaters and those scoring lower than 15 were classified as unrestrained eaters.

Procedure

In the first study, participants agreed to take part in an experiment investigating the effects of hunger on taste perception.  Sixty-eight female Introductory Psychology students as well as student volunteers were administered a consent form, followed by the Restraint Scale (Herman & Polivy, 1980). After the completed Restraint Scales were scored, only those individuals scoring a 15 or higher were asked to return for follow-up procedures.  Of the total sixty-eight participants that were originally administered the Restraint Scale, thirty-five were classified as restrained eaters, and therefore asked to return.  Of the thirty-five restrained eaters that were contacted, only ten of them ultimately took part in the study.  The ten restrained eaters were then randomly assigned to one of two dieting conditions.  All participants were told they would perform a taste perception task and then return on another date to perform additional testing. 
Participants assigned to the weeklong dieting condition were told that, immediately following the study; they would start a regulated diet for seven days.  These participants were shown a dieting meal plan.  The fictional meal plan was taken directly from Urbszat, Herman, & Polivy’s (2002) study, the only difference being that the title was changed to The Saint Anselm College Student Meal Plan (See Appendix D).  The meal plan was a low fat, calorie reduced diet, which consisted of slim fast shakes and lean cuisine meals.  Participants were also informed of specific guidelines laid out by the meal plan regarding which foods were forbidden to eat.  The high calorie forbidden foods included, chips, soda, cookies, ice cream, fried foods, pizza, and popcorn.
    Although participants were not actually required to go on a diet, it was important for the study that the participants genuinely believed that they would be requested to comply with the meal plan for however long the duration of their anticipated diet before returning to the laboratory.  Due to the use of deception, this study was reviewed by the Saint Anselm College Institutional Review Board.
    Participants in the forty-eight hour dieting condition were given a slightly modified version of the previously described procedure.  Due to a number of difficulties presented in the weeklong dieting condition, the participants in the forty-eight hour dieting condition were given a less strict diet to follow.  In fact, participants in this condition were not given a meal plan at all.  Instead, the participants were instructed to only eat 2,000 calories a day and restrict themselves from the same “forbidden” foods that the weeklong dieting condition participants were asked to.  The modification of this diet was done as a means to keep participants from walking out on the study, which is what happened in the previous condition, due to complaints of the diet being too strict.
    Participants in both conditions were presented with three plates of food, bottled water, and a taste-rating form.  The first plate consisted of Oreos, the second, chocolate chip cookies, and the third, cupcakes.  Participants were asked to rate each food type based on dimensions listed on the rating forms (See Appendix E).  Subjects were then instructed to have as much food as was necessary to achieve accurate ratings, which would provide a baseline measure of taste perception against which to compare ratings after the duration of the diet.
    Participants were then given 10 minutes to perform the taste-rating task.  During this time, participants were observed from behind a two-way mirror, and individual amounts of food were recorded.  When 10 minutes had elapsed, a manipulation check was conducted by asking participants to rate the likelihood that they would stick to the diet and how much weight they expected to lose during the duration of the diet (See Appendix F). 
    After completing the study, participants were thoroughly debriefed about the true purpose of the study and told that they would not be required to actually follow through with any diet or return to do another taste-rating task.  The use of deception in this study was explained, and all questions about the study were answered.  Participants were also given information regarding counseling services offered through the college.

Study 2:
Participants
   
Twenty female undergraduate students from Saint Anselm College were recruited as participants for this study.  All of the subjects were student volunteers who received no form of compensation in return for their participation.  Participants ranged in age from 18-22 and all were treated in accordance with the ethical standards set fourth by the APA.

Materials
  
 Instruments were given to the participants concerning the nature and purpose of the study.  A consent form was also distributed detailing the rights of the participants.
    The Restraint Scale (Herman & Polivy, 1980) as well as a food checklist was administered to the participants.  The food checklist was created by the experimenter and consisted of a list of foods provided by the Saint Anselm College Coffee Shop (See Appendix G). 

Procedure
   
Participants agreed to take part in a follow up study examining food preference as a result of eating behavior. Participants consisted of 10 restrained and 10 unrestrained eaters who were recruited based on their Restraint Scale scores collected in a previous study.
    All participants were asked to imagine a hypothetical situation in which they would be asked to take part in a two-day water fast following the termination of this study.  Based on this information, participants were administered the food check-list and asked to check off the foods they would most like to eat the night before going on the diet.  Participants were then debriefed about the true purpose of the study, and all questions regarding the use of slight deception were answered. 



Results

Study 1:

Sixty-eight female Introductory Psychology students as well as student volunteers were originally administered the Restraint Scale (Herman & Polivy, 1980).  Of the total sixty-eight participants that were administered the Restraint Scale, thirty-five were classified as restrained eaters, and therefore asked to return.  Of the original thirty-five restrained eaters, only eight showed up to take part the weeklong dieting condition.  Of these nine participants, five left the study because they did not want to participate in the anticipated diet.  When questioned on their motives for not partaking in the diet, participants gave one of two answers: (1) “ I am already on a diet and don’t want to have to change it” Or (2) “I play a sport and this will interfere with my training.”  The two-day dieting condition yielded a total of six participants.  The final number of participants in each condition were as follows: weeklong-day diet condition, restrained eaters, n = 4; two-day diet condition, n = 6.
Due to the small sample size, no statistical analyses were able to be performed, however, a significant amount of qualitative data was obtained.  Ultimately, the results supported the hypothesis that restrained eaters in the weeklong dieting condition would eat more in the initial taste-rating than restrained eaters in the two-day dieting condition, was supported.  The four restrained eaters in the weeklong dieting condition consumed a total of 19 ½ pieces of food, while the six restrained eaters in the two-day dieting condition only consumed a total of 14 ½ pieces of food.
When participants were finished with their taste-rating task they were asked to fill out a final questionnaire, which served as a manipulation check for the experiment.  One part of the manipulation check asked participants to indicate the extent to which they believed they would be able to stick to the diet.  On a Likert scale ranging from 1-5 (1=not at all, 5=completely), the overall mean for restrained eaters in the weeklong dieting condition (M=4.75) as well as for restrained eaters in the two-day day dieting condition (M=4.16) suggests that participants believed they would be able to stick to the diet relatively well.  Another part of the manipulation check asked participants to indicate how much weight they expected to lose on the diet.  As expected, the mean number of pounds expected to be lost by the restrained eaters in the weeklong dieting condition (M=3.71) was slightly higher than the restrained eaters in the two-day dieting condition (M=1.41).  This simply shows that the participants were realistic in their expectations of anticipated weight loss.  It only makes sense that a weeklong diet would yield more weight loss than that of a two-day diet. 

Study 2:
   
An independent t-test was used to compare the mean scores of “fattening” foods consumed by restrained and unrestrained eaters.  Unrestrained eaters chose to eat less items considered “fattening” (M=6.7, SD=3.43) than did restrained eaters (M=14.0, SD=4.44) when anticipating a hypothetical two-day water fast (See Figure 1).  The results ultimately showed that there was a significant difference between restrained and unrestrained eaters when it came to food choice (t (18) = -4.109, p< .001; restrained eaters choosing the fatter foods.



Discussion

Ultimately, both hypotheses of this study were supported.  In the first study, it was hypothesized that in an experimental situation in which restrained eaters were made to anticipate a weeklong diet, more food would be consumed than by restrained eaters made to anticipate a two-day diet.  The results were in support of this hypothesis, with restrained eaters in the weeklong dieting condition eating a total of 19 ½ pieces of food and the restrained eaters in the two-day dieting condition eating a total of 14 ½ pieces of food.  This seems to substantiate the original assumption that disinhibition is proportional to the length of the anticipated diet.  In other words, according to these results, the longer the duration of the anticipated diet, the more disinhibited restrained eaters will be in their consumption of food.  Therefore, food consumption is dependent on the duration of the anticipated diet. 
In the Second study, it was hypothesized that restrained eaters would choose high-calorie foods and unrestrained eaters, lower calorie foods to eat when anticipating a hypothetical 2-day water fast.  This was supported with the mean number of high calorie foods chosen by restrained eaters being 14.0 and the mean number of high calorie foods chosen by unrestrained eaters only being 6.7. These findings show support that anticipated deprivation effects food intake in restrained eaters, however it does not have implications for how the duration of anticipated deprivation effects restrained eaters.  There were some limitations to this study which may have effected the overall findings.  To begin with, the sample size in the first study proved too small to yield statistical analyses (n=9).
Many participants dropped out of the study because they did not want to partake in the anticipated diet, this finding was of particular interest due to the fact that the opposite was found in a similar study done by Urbszat, Herman & Polivy (2002); instead of participants refusing to partake in the anticipated diet, experimenters were surprised at the amount of participants willing to go on a diet for one week.  Another limitation has to do with the restraint scale itself.  Researchers have questioned the ability of the Restraint Scale (Herman & Polivy, 1980) to truly identify restrained eaters.  Other measurements such as the Dutch Eating Behavior Questionnaire (Van Strien, Frijters, Staveren, Defares, & Deurenberg, 1986) and the Three-Factor Eating Questionnaire (Stunkard & Messick, 1985) have shown to be more accurate in identifying restrained eaters.
 Finally, in the second study, the food checklist was designed only by the author of this study and was not developed with the help of a professional. Future studies are advised to have professionals unrelated to the research create the food checklist.



Acknowledgements


I would like to begin by thanking my mother, grandmother, and aunt for their unconditional support and love, without which I never would have had the strength to finish this thesis.  I would also like to take this opportunity to thank all my friends, especially my roommates, who were always able to put a smile on my face when I was stressed out. There are a few friends in particular that I would like to say a special thank you to: Meghan, thank you for always helping me to look on the bright side-- I honestly don’t think I could have made it through this without you; andHannah, thank you for being my partner through it all--you made sitting through experimental much more tolerable.
Most importantly I would like to thank my professors for helping me accomplish an endeavor that at first seemed insurmountable.  Specifically, I would like to thank professor Finn for instilling a sense of confidence within me.  Without this self-assurance I would not have been able to persevere and ultimately accomplish such an incredible task.  I would also like to thank professor Troisi for introducing psychology into my life in a manner that was both interesting and comprehensible, as well as for helping me develop the origins of this thesis.    



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Relevant Links

Saint Anselm College
National Eating Disorders Association
Dieting Detox
APA
Finding Balance