I recently heard a podcast about the Minnesota Starvation Experiment and found the research particularly interesting. Though the experiment took place in the 1940's, it is still referenced today when studying the physical and mental effects of starvation. The study would not be allowed today because of the ethical laws on human experimentation, but it was an extremely eye-opening experiment.
How it all began
In the mid 1940's, it was clear that World War II would end with thousands of starved and malnourished people. Little was known at the time about human starvation and how to best refeed civilians who had been food deprived for so long. Ancel Keys, a professor of physiology at the University of Minnesota, decided to conduct an experiment to help the world understand the psychological and physiological implications of prolonged and severe starvation and the best way to refeed.
Over 400 men responded to a flyer that read "Will You Starve That They Be Better Fed?" Of these 400 men, 36 healthy individuals were chosen to participate in a year long study. Those who inquired about the study were conscientious objectors who did not believe in fighting in the war due to their nonviolence beliefs but were willing to participate in a study that would help those after the war. On November 19, 1944, these men entered a laboratory at the University of Minnesota and the study began.
The first three months of the experiment were used to get the men at optimal weight and monitor them. They were fed around 3200 calories which sounds like a lot, but most of these men worked in active jobs and needed to eat more to maintain their weight. The next six months was the period of semi-starvation where calories were reduced to around 1600. The men were required to run or walk at least 22 miles per week and their rations were adjusted to meet the weekly weight loss goal of two pounds.
Meals were given twice daily, once in the morning and again in the evening. There was one day a week where they were given an extra meal. Meals typically consisted of a combination of cabbage, turnips, milk, rye bread, and beans and men lost at least 25% of their body weight during this time.
The men were allowed to leave the facilities to see their families, but after one was found sneaking in food, a buddy system was implemented to keep everyone accountable. Only 32 of the 36 men were used in the final study because some dropped out or were disqualified.
The 24 weeks of starvation was followed by 12 weeks of restricted rehabilitation. The men were divided into four groups, each receiving different and specific amounts of macronutrients, calories, and vitamins. The final eight weeks of the study was the unrestricted rehabilitation period where participants could eat whatever they wanted and how ever much they wanted. Their caloric intake and was still recorded and the participants were still monitored during this time.
When the starvation period began, food quickly became an obsession for the participants and several mental changes became obvious. They would add water to their food to make the meal more filling and started licking their plates clean. Coffee and gum eventually had to be limited because men started drinking excessive amounts tea and coffee a day and up to 30 and 40 packs of gum a day.
The men started reading cookbooks in their free time who had no previous interest in cooking and several expressed interest in becoming chefs once the experiment concluded. They noted that during movies all they would notice was what the characters were eating. Many participants suffered from severe depression, reduced concentration and comprehension, social withdrawal, hysteria, and emotional distress. One participant cut off three of his fingers with an axe though it is unclear, even for him, if it was intentional or from pure exhaustion.
Physically, many participates experienced swollen ankles, fatigue, anemia, headaches, dizziness, constant coldness, lowered heart rate and respiration, constipation, and a decreased sex drive. There was also a decrease in their basal metabolic rate which is the energy needed at rest for the body to maintain basic bodily functions such as breathing, digestion, brain function, and maintaining a heart rate.
During the refeeding period, men ate as much as 11,000 calories a day. Several participants noted that no matter how much they ate, they still felt psychologically hungry. One man was hospitalized and had to get his stomach pumped from eating so much.
57-year follow up
The importance and significance of this study was clear to physicians, doctors, and dietitians. However, what was still unclear, was the long term effects of starvation, even after full recovery. So researchers decided to track down 19 of the surviving participants, who were in their 70 and 80's, and get their subjective thoughts on what long-term effects the faced due to the semi-starvation experiment.
Several of the men discussed the struggle they had to maintain their body weight, which lasted between six months and five years after the experiment ended. Several also spoke of their short term struggle with binge eating during the refeeding period and even a few months after the study. None of the men had issues with binge eating before the experiment.
Two of the men said that during the starvation period, they viewed others, including staff conducting the study, as being overweight. Others said they were unaware of their own skeletal appearance though they noticed the other participants becoming very thin. Seven men said during the rehabilitation period, they were concerned about fat accumulation in the abdomen and buttocks, and five became bothered by how "fat" they felt after the rehabilitation period.
One man, three months after the beginning of rehabilitation, wrote in a journal, “During this week I regained my top standardization (control) weight: however it certainly is not in the same places as the 138 pounds I had on me when I came to Minneapolis. My arms, thighs, buttocks and midsection, all feel fuller than I can ever recall, my face also looks fatter. However, these reactions may be conditioned by what I got used to during semi-starvation.”
How the results of this experiment are used today
This experiment gives us insight to what the body experiences during extreme dieting. People often get frustrated that they easily gain weight back after stopping a diet but this is the body's natural physiological response after it has been deprived of nutrients. Many people do not realize the damage they do to their bodies during extreme dieting, but it can negatively effect their cognitive function at work and in school. Not to mention the host of negative physical symptoms that can come as well.
Both the physical and psychological effects that participants experienced are often seen today in those who suffer from eating disorders, especially anorexia. People with eating disorders often obsess about food and tend to withdrawal socially. It is common for them to suffer from lower heart rate, anemia, edema, constipation, and decreased basal metabolic rate. When the body goes into starvation mode, it does everything it can to slow bodily functions because it does not know when it will get food again.
The 6-month to 5 year period that it took the study participants to maintain their weight mirrors the recovery period of those with eating disorders. It is also common for those recovering from eating disorders to engage in binge eating behaviors. The Minnesota Starvation Experiment was an extremely important study showing the consequences of prolonged starvation as well as the long term refeeding process. It has helped those in the medical industry to understand both the physiological and psychological symptoms and complications of eating disorders, both short and long term.