The Minnesota Starvation Experiment

In November 1944, 36 young men moved into the halls and rooms of the University of Minnesota’s football stadium. These individuals were not football players but volunteers for a nearly yearlong study on the psychological and physiological effects of starvation. This study, known as the Minnesota Starvation Experiment, was conducted by the newly established Laboratory of Physiological Hygiene at the University of Minnesota, an interdisciplinary research center focused on nutrition and human biology.

At the time, World War II was raging around the world, and so, too, were hunger and starvation. Over the centuries, people have recorded anecdotal reports of the effects of famine and starvation, but there is little scientific literature that describes its physiological and psychological effects. Just as important, doctors and researchers didn’t know how to help people rehabilitate and recover from starvation.

Eager to take on the challenge was Ancel Keys, PhD, the physiologist in charge of the Minnesota lab. The lab’s chief psychologist, Josef Brozek, PhD, was responsible for gathering the psychological data on the effects of starvation. Brozek completed his doctoral degree in 1937 at Charles University in Prague with interests in applied psychology, physiology and physical anthropology and joined the Minnesota lab in 1941.

Among his duties, Brozek assisted in recruiting subjects for the study. In previous nutrition studies at the lab, Keys had drawn subjects from the ranks of the Civilian Public Service (CPS). During World War II, the CPS provided conscientious objectors an alternative to military combat service. These objectors were often referred to as human guinea pigs because of their willingness to serve in medical experiments. Keys knew from experience that many conscientious objectors were eager to do meaningful work that would benefit humanity and was confident that the starvation experiment would attract the needed volunteers.

Subject selection was stringent. Subjects had to be male, single and demonstrate good physical and mental health (largely based on the newly developed Minnesota Multiphasic Personality Inventory). They also had to show an ability to get along well with others under trying circumstances and an interest in relief work. The final 36 men were selected from more than 200 volunteers and in November 1944 made their way to the University of Minnesota to begin their service.

The research protocol called for the men to lose 25 percent of their normal body weight. They spent the first three months of the study eating a normal diet of 3,200 calories a day, followed by six months of semi-starvation at 1,570 calories a day (divided between breakfast and lunch), then a restricted rehabilitation period of three months eating 2,000 to 3,200 calories a day, and finally an eight-week unrestricted rehabilitation period during which there were no limits on caloric intake. Their diet consisted of foods widely available in Europe during the war, mostly potatoes, root vegetables, bread and macaroni. The men were required to work 15 hours per week in the lab, walk 22 miles per week and participate in a variety of educational activities for 25 hours a week. Throughout the experiment, the researchers measured the physiological and psychological changes brought on by near starvation.

During the semi-starvation phase the changes were dramatic. Beyond the gaunt appearance of the men, there were significant decreases in their strength and stamina, body temperature, heart rate and sex drive. The psychological effects were significant as well. Hunger made the men obsessed with food. They would dream and fantasize about food, read and talk about food and savor the two meals a day they were given. They reported fatigue, irritability, depression and apathy. Interestingly, the men also reported decreases in mental ability, although mental testing of the men did not support this belief.

For some men, the study proved too difficult. Data from three subjects were excluded as a result of their breaking the diet and a fourth was excluded for not meeting expected weight loss goals.

The men and the study became subjects of national interest, even appearing in Life magazine in 1945. But in some ways, world events overtook the study. The war in Europe ended on May 8, 1945, barely halfway through the starvation phase of the experiment. Keys and the men worried that the data they had sacrificed for would not get to relief workers and the starving people they wished to serve in time to help them. Relief efforts were underway and there was no clear guide for rehabilitating those who were starving.

In response, members of Keys staff prepared a 70-page booklet, Men and Hunger: A Psychological Manual for Relief Workers. The book provided practical advice based on lessons learned in the lab.

The Minnesota Starvation Experiment ended in October 1945. Its results painted a vivid picture of the physical and psychological decline caused by starvation and offered guidelines on rehabilitation. In the restricted rehabilitation, calories were increased in increments. The experiment also looked at unrestricted rehabilitation and — even though participants were warned against it — some engaged in extreme overeating. Of the various diets and supplements studied during the experiment’s rehabilitation phase, the most reliable weight-gain strategy was high caloric intake. Simply put, starving people needed calories. Food and lots of it was the key to rehabilitation. It was as true for those released from the laboratory in Minnesota as it was for those freed from the privations of war in Europe.

In 1950, Keys, Brozek and other members of the team published their data in the two-volume set “The Biology of Human Starvation,” which is still a landmark work on human starvation. The men who served as subjects went their separate ways, some into relief work, the ministry, education and other service-oriented occupations. Brozek, who had developed an interest in the history of psychology, would go on to Lehigh University and became a recognized psychology historian. Keys, who is well-known for his work on the Mediterranean diet, is also remembered for popularizing the body mass index. His contributions and visibility were significant enough to earn him a place on the cover of Time magazine in 1961.

The story of the Minnesota Starvation Experiment is many stories rolled into one. It reminds us of the privilege we have; most of us can avoid the unpleasant sensation of hunger by simply reaching for something to eat. Hunger is debilitating and tragic, all the more so when it is created by human affairs. The Minnesota Starvation Experiment also tells the story of service and sacrifice among those who served in the Civilian Public Service and raised questions about the ethics of human experimentation. Mostly, it reminds us that in psychology studies of mind and body, science and practice can converge to deal with real problems in the real world.

Key Lessons

1. Psychological Effects:
   • Increased Obsession with Food: Participants developed an intense preoccupation with food, often engaging in food-related behaviors such as hoarding recipes and discussing meals.
   • Emotional Disturbances: Depression, irritability, and mood swings were common among participants, highlighting the psychological toll of severe calorie restriction.
   • Social Withdrawal: Many participants became socially withdrawn and isolated, avoiding social interactions and activities they previously enjoyed.
2. Physiological Effects:
   • Metabolic Slowdown: Participants experienced a significant decrease in their basal metabolic rate (BMR), indicating the body’s adaptive response to conserve energy during periods of starvation.
   • Physical Weakness and Fatigue: Severe calorie restriction led to extreme physical weakness, fatigue, and a loss of interest in physical activity.
   • Edema: Some participants developed swelling in their extremities (edema), likely due to the body’s response to severe nutritional deficiencies.
3. Refeeding Phase:
   • Challenges in Refeeding: Rapid refeeding led to gastrointestinal distress, highlighting the importance of a gradual and monitored refeeding process after periods of severe calorie restriction.
   • Hyperphagia: Participants experienced periods of extreme hunger and overeating during the refeeding phase, which underscores the difficulty in returning to normal eating patterns after prolonged starvation.

Implications for Modern Weight Management Courses

1. Balanced Approach to Calorie Restriction:
   • Avoid Extreme Calorie Deficits: Severe calorie restriction can lead to both physical and psychological harm. Modern weight management should focus on moderate, sustainable calorie reductions.
   • Focus on Nutrient Density: Ensuring that individuals get sufficient nutrients even when reducing calorie intake is crucial to prevent deficiencies and associated health issues.
2. Psychological Support:
   • Address Emotional and Behavioral Aspects: Understanding that dieting can affect mental health, weight management programs should include psychological support to help individuals cope with potential emotional disturbances.
   • Develop Healthy Eating Behaviors: Encourage mindful eating practices and strategies to manage food preoccupation and emotional eating.
3. Gradual and Monitored Refeeding:
   • Controlled Refeeding Plans: After periods of calorie restriction, refeeding should be gradual and carefully monitored to prevent gastrointestinal distress and other refeeding-related issues.
   • Educate on Normalizing Eating Patterns: Provide guidance on how to transition back to regular eating patterns to avoid binge eating and ensure long-term success.
4. Understanding Metabolic Adaptations:
   • Awareness of Metabolic Slowdown: Educate individuals about the body’s adaptive mechanisms that can reduce metabolic rate during prolonged calorie restriction and how to counteract this effect.
   • Incorporate Physical Activity: Encourage regular physical activity to help maintain metabolic rate and preserve muscle mass during weight loss.

Conclusion

The Minnesota Starvation Experiment highlights the complex interplay between psychological, physiological, and behavioral factors during severe calorie restriction and refeeding. Modern weight management courses can draw from these insights to promote balanced, sustainable, and psychologically informed approaches to weight loss, ensuring that individuals achieve their goals in a healthy and supportive manner.

Look after yourself and live with intention!

References:

• Garner, D. M., Rockert, W., Olmsted, M. P., Johnson, C., & Coscina, D. V. (1985). Psychoeducational principles in treatment. In D. M. Garner & P. E. Garfinkel (Eds.), Handbook of treatment for eating disorders (pp. 147-177). New York, NY: The Guilford Press.
• 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.