THE STARVATION EXPERIMENT

To inform treatment, mental health providers often like to discuss research findings with their patients. It offers an opportunity for individuals to understand a providers reasoning for using a particular modality while eliciting change. For the treatment of eating disorders in particular, Garner (1997) recommends providing information from research or psychoeducation to individuals with eating disorders. It is suggested to be a core component of eating disorder treatment because it can act as a source of motivation and reduce defensiveness in patients (Garner, Rockert, Olmsted, Johnson, & Coscina, 1985). One of the most prominent studies used as a source of psychoeducation in eating disorder treatment is the Minnesota Starvation Study by Keys et al. (1950). Not only did it provide a wealth of knowledge about the psychological and physiological effects of starvation, a key component in anorexia nervosa, but it also offered insight into the rehabilitation/refeeding process. Discussing these findings helps our patients and providers understand the process of restrictive eating and how to implement adaptive refeeding. 

Origin 

During this time in history, starvation and other forced atrocities were occurring throughout Europe in World War II. It was clear there would be a critical need for a large-scale relief feeding (Keys et. al, 1950). As a consultant to the War Department and a professor of physiology at the University of Minnesota, Ancel Keys sought to explore how individuals would be affected physiologically and psychologically by a limited diet. Additionally and most importantly, he wanted to identify how he could best help these individuals in the refeeding process to provide postwar rehabilitation.  

What is the Minnesota Starvation Study? 

In November 1944, physiologist, Ancel Keys, and psychologist, Josef Brozek, conducted a study at the University of Minnesota to identify the best type of rehabilitation diet for individuals who had experienced starvation. In order to test types of refeeding, the researchers first had to conduct a study on semi-starvation. This additional exploration provided information about the effects of semi-starvation on the mind and body and offered significant insight into symptoms related to anorexia nervosa and bulimia nervosa.  

Recruitment Process 

To conduct this research, Keys et al. (1950) recruited thirty-six young, healthy men to participate in this almost year-long study. This was a difficult task due to many young men serving in the military at the time. Fortunately, there was a group of young men assigned to the Civilian Public Service in the United States and Keys received approval from the War Department to recruit from this sample. In order to participant in the study, individuals had to meet the following criteria: Must be in good physical and mental health; must be able to get along reasonably well with others; and must have a true interest in relief and rehabilitation. In order to have optimal motivation and cooperation in the study, the researchers believed that the participants needed to have a personal sense of responsibility in improving the nutritional status of famine victims. 

Study Activities 

Throughout the entire study, participants worked on tasks in the laboratory and were allowed to take university classes and participate in university activities.  Each participant was required to keep a personal journal of their daily lives within the study. The participants’ basic functions, body weight, size, and strength were recorded regularly. They were given psychomotor and endurance tests as they walked or ran on treadmills in their laboratory as well as intelligence and personality measures from psychologists (Keys et al., 1950). 

Phases 

The experiment was conducted in the following way: The first 12-weeks was a control period, the next 24 weeks involved semi-starvation, and the last 12-weeks involved controlled rehabilitation. An additional 8 weeks of unrestricted rehabilitation was held for twelve of the subjects. For 8 to 12 months following the starvation recovery, the study conducted follow-up examinations.  

During the first three months, the researchers observed and collected data about their participants’ normal eating behaviors. The participants ate food provided by a full-time cook and two assistants under the supervision of a trained dietitian. Each individual’s meals were adjusted to their body size in order to maintain caloric balance. They consumed around 3500 calories of food per day and were determined to have had an appropriate amount of nutrients and vitamins. 

For the following six months, the men’s diets were restricted to half of their normal intake to reflect the conditions of war in Europe. They were served two meals a day and ate approximately 1570 calories a day. As a result, they lost approximately 25% of their weight.  

For the final three months of the study, participants were refed and rehabilitated. They were divided into 4 groups and refed with different caloric amounts starting at a low quantity. A small group of subjects stayed for an additional 8 weeks and were fed an unrestricted diet. During those first two weeks of the unrestricted diet, each participant was allowed to choose their own meals and consequently ate between 7,000-10,000 calories per day.  

Results and Observations 

After reviewing and analyzing the data collected throughout the baseline, starvation period, and refeeding/rehabilitation period, notable changes were observed in physical, psychological, behavioral, and social aspects of the volunteers’ lives. Not only had the participants’ bodies’ gone through physical changes, but their psychological well-being had been impacted. 

Cognitive Differences. First, Keys et al. (1950) noticed a significant difference in the themes of the participants’ cognitions. Compared to the start of the study, the participants were far more preoccupied with food. Food and eating became focal points in conversations, reading, dreams, and even daydreams. For example, when they watched movies, the study’s participants were recorded commenting on the frequency of food and eating mentioned. Some volunteers developed concentration issues due to their preoccupation with food. Additionally, their interest in food expanded into new habits of reading cookbooks and collecting recipes (Garner & Garfinkel, 1985). Three participants even changed their occupations to reflect their extreme interest in eating and food: Three became chefs and one went into the agriculture field (Keys et al., 1950). 

Eating Changes. Second, Keys et al. (1950) observed changes in the participant’s baseline behavior. During mealtimes, participants were recorded becoming possessive over their food. Worried that others may try to eat their meals, they would guard their food defensively with their elbows. At meal times, participants were recorded eating all the food on their plates to the “last crumb” and “licking” their plates clean. Some even became upset when non-participants in the cafeteria “wasted” food.  

Moreover, those that enjoyed gum started chewing to excess. Gum-chewing became a health concern due to participants “rapidly” chewing 2-3 sticks at a time until their mouths became sore. The researchers had to place a cap on gum packages chewed per day to two. Others developed tobacco-smoking habits because it provided some relief from the hunger they experienced during the semi-starvation phase. 

During the rehabilitative phase, more eating behaviors developed. Men started eating “several” meals in one sitting and developed gastrointestinal upset and headaches as a result. They experienced difficulties in reading their own hunger cues. Participants described feeling hungrier and using binge-eating and purging behaviors during the refeeding period. Even after five-months of refeeding, they continued to use these behaviors and developed body image concerns. 

Behavioral and Personality Changes. Many were observed collecting food-themed items and even rummaging through garbage to find food. The participants developed an extreme distaste for wasting food. Such behaviors have been observed in individuals with anorexia nervosa (Crisp, Hsu, Harding, & Hartshorn, 1980). Similarly, participants used methods to create the illusion that they had more food on their plates than in reality. They started “toying” with their food, cutting it into small pieces, and making their meal consumption last for hours, which previously would have lasted minutes. There was also a remarkable increase in the use of spices and salt to add flavor to meals. Moreover, participants who had been mostly extraverted in their social life, became isolated and described themselves as feeling socially inadequate. Keys et al. (1950) also reported a decrease in the sex drive and interest of their volunteers. 

Emotional Changes. During the semi-starvation and the rehabilitative phases, participants were recorded developing new anxiety and depressive symptoms not present at the beginning of the study. Using the Minnesota Multiphasic Personality Inventory (MMPI), Keys et al. (1950) recorded significant increases on the Hysteria, Hypochondriasis, and Depression scales indicating increased anxiety related to somatic concerns and depressive symptoms. Especially during the semi-starvation period, some participants endorsed becoming more sensitive and argumentative with others. Over the first 6 weeks of the rehabilitation period, many men reported feeling even more depressed than the semi-starvation phase; especially those individuals in the rehabilitation group that were fed less calories in the beginning of the phase to test refeeding strategies. Keys et al. (1950) remarked that the only times these participants showed positive emotional reactions were in response to discussing their weight, food, or hunger. 

Physical Observations. Lastly, the participants’ physical changes throughout the experiment were significant. Not only had the participants’ weight changed during the different stages of the study, they started to experience new issues with gastrointestinal discomfort, dizziness, headaches, decreased need for sleep, edema, hair loss, and cold intolerance. Even their basal metabolic rate (BMR), or amount of energy in calories the body requires at rest, changed depending on the stage of the study. By the end of the semi-starvation period, the volunteers’ BMRs had decreased by 40% from their baselines. Keys et al. (1950) suggested that this was due to the low caloric intake which reduced the body’s need for energy. Additionally, in the semi-starvation period, the volunteers’ weight dropped by 25% and their muscle mass decreased by 40%.  

What does this all mean? 

Keys et al. (1950) originally explored optimal methods for the refeeding of individuals following starvation. In order to do so, the researchers had to conduct a study in which healthy participants were voluntarily semi-starved. As a result, Keys et al. (1950) discovered a wealth of knowledge pertaining to the detrimental effects of starvation and restriction to physical and psychological functioning. The men in this study were healthy physically and psychologically at the beginning of the experiment. Following semi-starvation, the participants developed symptoms similar to those of anorexia nervosa, bulimia nervosa, and binge-eating disorder.  

Understanding the findings from this study is important for several reasons. First, it may provide insights into why starvation may be reinforcing for some individuals. The description of the experience of extreme caloric restriction sounds aversive. Yet, it is possible that the food preoccupation that accompanies extreme caloric depletion is reinforcing in the sense that the individual struggling thinks less about other things that may be stressful – but seemingly less in the individuals’ “control.” In this way, the starvation of anorexia nervosa is functioning as a distraction or avoidance behavior. At the same time, this preoccupation may give individuals with anorexia nervosa the mistaken impression that there is not much that constitutes who they are other than restricting food – thereby making the prospect of recovery quite scary. Thus, understanding that this is an artifact of starvation can be very hope producing. Second, it may help parents have a greater understanding of some of the perplexing and sometimes frustrating behaviors that arise during the course of meal management (e.g., slow eating, shredding food). By appreciating that these are adaptations of starvation rather than overt acts of defiance, parents may be in a better position to understand the behaviors of their children.  

In summary, this study suggests that the act of restriction and extreme dieting impacts an individual’s physical, social, behavioral, and psychological well-being. To this day, the Minnesota Starvation Study is considered one of the most critical pieces of psychoeducation to share in the treatment of eating disorders.

By Chantal Gil, PsyD

References 

Crisp, A. H., Hsu, L. K. G., Harding, B., & Hartshorn, J. (1980). Clinical features of anorexia nervosa: A study of a consecutive series of 102 female patients. Journal of Psychosomatic Research, 24(3), 179-191. 

Garner, D. M. (1997). Psychoeducational principles in treatment. In D. M. Garner & P. E. Garfinkel (Eds.), Handbook of treatment for eating disorders (pp. 147-177). New York, NY, US: The Guilford Press. 

Garner, D. M., & Garfinkel, P. E. (1985). Handbook of psychotherapy for anorexia nervosa and bulimia. Guilford Press. 

Kalm, L. M., & Semba, R. D. (2005). They starved so that others be better fed: remembering Ancel Keys and the Minnesota experiment. The Journal of nutrition, 135(6), 1347-1352. 

Keys, A., Brozek, J., Henshel, A., Mickelson, O., & Taylor, H.L. (1950). The biology of human starvation, (Vols. 1–2). Minneapolis, MN: University of Minnesota Press.

Tucker, T. (2007). The great starvation experiment: Ancel Keys and the men who starved for science.Minneapolis, MN: University of Minnesota Press. 

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