1944 Minnesota Starvation Experiment

The 1944 Minnesota Starvation Experiment was a medical and psychological study designed to find solutions to the widespread hunger and malnutrition crises faced by civilian populations toward the end of World War II. Conducted at the University of Minnesota’s Laboratory of Physiological Hygiene by physiologist Ancel Keys and psychologist Josef Brozek, the study aimed to map the effects of prolonged caloric restriction on human physiology and psychology and to determine the most effective refeeding strategies for postwar relief efforts. The experiment’s data and findings were published in a comprehensive monograph in 1950.^【1】

Visual representation of the 1944 Minnesota Starvation Experiment (generated by artificial intelligence)

Background and Selection of Participants

Famine in Europe and Asia during the war became an urgent medical issue as Allied forces encountered weakened civilian populations on the brink of starvation. Ancel Keys, then an advisor to the U.S. War Department, sought volunteers among conscientious objectors who had refused military service and were performing alternative civilian duties. From approximately 400 applicants who responded to distributed brochures, candidates were filtered through interviews to identify individuals with sound physical and mental health, good group cohesion, and strong motivation to contribute to the rehabilitation of war victims.^【2】 Ultimately, 36 healthy young men were selected as subjects, capable of enduring the rigorous physiological tests.^【3】

Phases and Methodology of the Experiment

The research consisted of three consecutive phases, during which participants’ weight, basal metabolic rate, blood values, cardiac function, and psychological profiles were meticulously recorded at each stage.

Visual representation of the 1944 Minnesota Starvation Experiment (generated by artificial intelligence)

• Standardization Phase (12 Weeks): During the initial three-month period, participants’ normal eating habits and caloric needs were established. They were provided with nutrient-dense meals totaling approximately 3200 to 3500 calories per day, tailored to their body size and energy expenditure.^【4】 Participants reported feeling physically energetic and actively participated in university courses and social activities during this phase.
• Semi-Starvation Phase (24 Weeks): Participants’ diets were halved and restricted to carbohydrate-heavy foods such as potatoes, turnips, Swedish turnips, pasta, and whole grain bread, intended to mirror conditions in war-torn Europe. Daily caloric intake was reduced to between 1570 and 1800 calories, and subjects were required to walk approximately 35 kilometers per week and perform specific laboratory tasks to maintain energy expenditure.^【5】 The goal was for participants to lose approximately 25 percent of their initial body weight during this phase.^【6】
• Rehabilitation and Refeeding Phase (12 Weeks): After the starvation period, participants were divided into four groups and given refeeding diets differing in caloric, protein, and vitamin content. In subsequent weeks, some participants were also offered an additional eight-month period of free feeding, during which they could choose their own foods.^【7】

Physiological and Physical Effects

As the semi-starvation phase progressed, the body redirected energy use toward vital organs, suppressing other systems to sustain life. Early findings included a 40 percent reduction in basal metabolic rate and persistent feelings of cold due to the inability to maintain body temperature.^【8】 Cardiac muscle weakened, blood pressure and pulse rate declined, and participants developed shortness of breath and iron-deficiency anemia due to energy insufficiency.

Visual representation of the 1944 Minnesota Starvation Experiment (generated by artificial intelligence)

Visible physical changes included prominent ribcages, hair loss, dry skin, and severe edema in the lower limbs. Systems responsible for producing reproductive hormones such as testosterone were suppressed due to energy deficiency, and sexual desire disappeared entirely as a result of cellular breakdown.

Psychological, Emotional, and Behavioral Effects

Food restriction altered the brain’s neurochemical structure, leading to significant behavioral deviations. Participants developed an obsessive preoccupation with food. When watching films, they focused not on the plot but on scenes involving meals; they began reading cookbooks and collecting recipes as a habit. Some even decided to change careers to become chefs or farmers.

Observers noted that participants guarded their food by shielding it with their arms, developed extreme sensitivity to waste, and began rummaging through trash. New behaviors emerged to create a greater sense of fullness: cutting food into tiny pieces, stretching meal times over long periods, diluting portions with water to make them appear larger, and using excessive salt and spices to stimulate taste. To suppress hunger, participants developed compulsive habits such as chewing up to 40 packs of gum per day, beginning tobacco use, or biting their nails. Two participants were disqualified from the study after being caught stealing ice cream or extra vegetables by chewing them raw.Minnesota Multiphasic Personality Inventory results showed that participants who initially had normal mental health developed symptoms of depression, social isolation, hysteria, hypochondriasis, and outbursts of anger.^【9】

Visual representation of the 1944 Minnesota Starvation Experiment (generated by artificial intelligence)

Rehabilitation Findings and Impact on Modern Medicine

The refeeding phase demonstrated that returning to a healthy weight and rebuilding tissue could not be achieved through standard diets. Transitioning to normal caloric intake did not immediately result in weight gain; participants required months of consuming between 4000 and 10,000 calories per day. When free feeding was introduced, many subjects experienced persistent hunger, loss of control, and binge-eating episodes, leading to severe gastrointestinal distress. Full recovery of physical strength and previous psychological states took years.

The Minnesota Starvation Experiment is now used in modern psychiatry to explain the mechanisms of anorexia nervosa and eating disorders such as bulimia nervosa. The findings revealed that symptoms such as food obsession, rigid rituals, and mental distress caused by dietary restriction are not merely psychological but are physiological and inevitable responses of the body to starvation.