What the Great Starvation Experiment Taught Us
You may have heard of it: the Minnesota Starvation Experiment. This was a clinical study performed at the University of Minnesota in 1944-1945 to determine the physiological and psychological effects of severe, prolonged dietary restriction and the effectiveness of different rehabilitation strategies.
Why Starve People?
One of the largest killers of World War II was hunger. Millions of people in Europe were suffering from famine and doctors did not know how to help them because almost no scientific information existed for definitive treatment. For relief efforts after the war to be effective, we needed information.
Lead investigator, Dr. Ancel Keys, recruited 36 men to participate in the starvation experiment. These were healthy, young (22-33 years old), white males who demonstrated evidence of the required mental and physical health and commitment to the objectives of the study. These men were conscientious objectors and volunteered to participate as an alternative to their military service.
While too late to help in postwar recovery efforts, Keys published the results of the experiment in a 1,385-page text (The Biology of Human Starvation). Preliminary pamphlets containing the key results were able to be distributed to aid workers in Europe and Asia, however, and were heavily relied on following the end of the war.
What Was Involved?
The 1-year study had four phases:
- Control Period (12 weeks): standardization period – participants received a controlled diet of ~3,200 kcal per day and participants maintained close to their calculated “ideal” weight. Subjects were also required to walk 22 miles each week and keep a personal diary. Metabolic and physical measurements, x-rays, treadmill tests, and intelligence and psychological evaluations were collected.
- Starvation Period (24 weeks): 6 months of semi-starvation during which calories were cut in half (~1,560 kcal per day) made up primarily of foods that were expected to make up the diets of people in Europe during times of war – potatoes, bread, macaroni, turnips, cabbage – high in carbohydrates, low in protein and split between two daily meals. The goal was a weight reduction of 25% by the end of the diet period. This included 22 miles per week of walking.
- Rehab Period (12 weeks): subjects were split into four groups, each receiving different calorie levels above the starvation level of calories (400, 800, 1200, or 1600 additional calories). Some also received vitamin and protein supplementation.
- Unrestricted Rehab Period (8 weeks): calorie intake was not controlled and subjects could eat ad libitum, however intake was still recorded and monitored.
And, no, no one died. Subjects were carefully monitored. Unlike the free-living world where 9 million people die from hunger every year – more than malaria, AIDS, and tuberculosis combined.
Mental apathy, severe emotional distress, depression, preoccupation with food, ritualized eating practices, edema, hair loss, paresthesia (burning or prickling sensation), hypersensitivity to noise and light, reduced strength, GI discomfort, dizziness, headaches, social withdrawal and isolation, decreased sex drive, decreased basal metabolic rate, mood changes, fatigue, as well as lower body temperature, respiration, and heart rate. Some of the men had enrolled in classes at the university for something to do during the study and to provide a distraction, and a few dropped out of class over the course of the starvation period due to fatigue and feeling like they were unable to concentrate. The men, in their own minds, did not perceive themselves as being excessively thin. They actually began to think that everyone else looked too fat, rather than they themselves being too thin.
Initially, Keys allowed his subjects unlimited chewing gum, water, and black coffee, but the men were chewing as many as 40 packs of gum a day and drinking up to 15 cups of coffee and limits were later enforced. A “buddy system” also had to be incorporated after subjects were found to be sneaking food during the starvation phase by going in to town.
After the starvation phase, Keys did not significantly increase their calories. Subjects were entered into one of four groups (+400, +800, +1200, or +1600 kcal above starvation level) to investigate the optimal amount of calories for rehabilitation. The men in every group felt like they were barely getting any more food than before. Keys concluded that about 4,000 calories per day for several months was needed to rebuild strength in a person recovering from starvation, more than he originally thought. He also aid that starvation did not appear to have any significant, long-term negative health impacts.
I would agree to disagree here. While one, six-month period of semi-starvation may not have long-term health impacts on these men, what about those who have a long history of dieting? What about women? What about children?
During the rehabilitation process, many of the subjects reported uncontrollable hunger and binge eating, reporting daily intakes of anywhere from 5,000-12,000 calories. Some reported the rehabilitation period to be the most difficult part of the experiment – several continued to lose weight after being provided more food (most likely due to subsiding edema). None were given detailed instructions for recommended diet or activities after they left with some estimating recovery took them anywhere from 2 months to 2 years to to feel fully recovered.
After the study ended, the participants did not become obese. Yes, they gained back to their original weight, plus about 10%. Then their weight gradually tapered down to pre-experiment levels over the next 6 months. It took about 8 months of rehabilitation for the men to recover their interest in sex – a clue to how long it takes the body to return hormone levels to normal after prolonged dieting – and for most of the men to return to normal eating patterns. Upon follow-up, they say that for many years they were afraid that food might be taken away from them again.
How Is This Helpful Today?
True, these men were part of a voluntary, controlled study and did not self-impose starvation on themselves. They were “victims of circumstance” unable to control their environment, as would be more realistic to the original goal of assisting those who are in starvation due to the political climate of where they live – perhaps as prisoners or citizens of a war-torn area. They were also probably given more food than those who they were intending to help and they at least knew when their torture would end.
However, the study has still been beneficial to those in the eating disorder recovery field.
The physical and psychological effects that came about during the study are similar to those experienced by people with eating disorders such as anorexia nervosa and bulimia nervosa. Remember, none of these men had problems with food or their bodies before the study began, but through the course of (controlled and monitored) semi-starvation, they exhibited many of the same characteristics as those with a range of eating disorders.
Because many of the symptoms associated with eating disorders were also observed in this study, some researchers believe that the psychological as well as physiological side effects may be due to under-nutrition. It also shows that weight needs to be returned to “normal” levels (or maybe even higher) for psychological functioning to return to “normal” levels as well. Weight gain is a requirement of the eating disorder treatment process – the psychological issues cannot be dealt with in a starved body.
It should be noted that the amount of calories that were used for the starvation period (about half of normal intake) is not a ludicrous amount. Compare that to many medically-supervised (and non-supervised, such as fad diets or other programs you can find and follow from online or books) weight-loss programs, which may restrict calories even lower. Is it any wonder why many of these programs are successful in the short-term but then usually result in the dieter gaining the weight back (if not more) down the road?
So, while a starvation study could not “ethically” be done today, aren’t we already doing starvation studies on ourselves in that wide world known as diet culture?
“Even people who are at a healthy weight and not inclined toward disordered eating become obsessed with food and eating when they are deprived of adequate nourishment or subjected to restrictive eating.”
Oh, and the men, upon interview almost 60 years after the study’s conclusion, said that they would do it all over again, even after knowing the suffering that they had experienced. They wanted to help people and most continued on with other humanitarian efforts.