Diets Debunked

During the Second World War, as famine ravaged parts of Europe, scientists became increasingly concerned about how to help starving populations recover after the conflict. This led to one of the most revealing and ethically complex studies in nutrition science: the Minnesota Starvation Experiment. Conducted in 1944-1945, this study sought to understand the physiological and psychological effects of prolonged calorie restriction and the best methods for refeeding malnourished individuals.

What Was the Minnesota Starvation Experiment?

The experiment was led by Dr Ancel Keys and his team at the University of Minnesota. They recruited 36 healthy male volunteers, all of whom were conscientious objectors to the war. These men were selected for their physical and mental resilience, as the study would push them to extreme limits.

The study was divided into three phases:

1. Control Period (12 weeks): The men ate normally while their baseline health and metabolism were recorded.
2. Starvation Period (24 weeks): Their calorie intake was halved, reducing them to around 1,570 calories per day, while they were required to walk 22 miles per week to increase energy expenditure.
3. Refeeding Period (12+ weeks): The men were gradually reintroduced to higher calories to study recovery.

The Findings: Physical and Psychological Effects

The results were profound, illustrating just how devastating calorie restriction is on both body and mind.

Physical Changes

• Rapid weight loss (around 25% of their body weight).
• Decreased muscle mass, strength, and endurance.
• Lowered heart rate and body temperature (signs of a slowed metabolism).
• Severe fatigue, dizziness, and oedema (swelling from fluid retention).

Psychological and Behavioural Effects

• Obsessive thoughts about food, including collecting recipes and hoarding utensils.
• Increased irritability, depression, and social withdrawal.
• Loss of libido and general apathy.
• Some men even resorted to chewing excessive amounts of gum (up to 40 packs a day) to cope with hunger.

Refeeding: A Slow and Complex Process

When the men were allowed to eat more again, their recovery was not straightforward. Many experienced extreme hunger, binge-eating behaviours, and continued psychological distress. Some never fully regained their pre-experiment relationship with food.

Interestingly, those who were given higher protein and calorie diets during refeeding recovered faster, but they also gained significant fat, suggesting that the body prioritises restoring energy stores after deprivation.

Modern Applications: Weight Loss, Dieting, and Metabolism

The Minnesota Starvation Experiment holds crucial lessons for today’s discussions on dieting, weight loss, and metabolism.

1. Extreme Calorie Restriction Is Unsustainable

The men in the study were eating roughly what many modern crash diets recommend (1,500-1,600 calories). Yet, they suffered physically and mentally, proving that severe restriction is not a healthy or maintainable way to lose weight.

2. The Body Fights Weight Loss

As the men lost weight, their metabolisms slowed dramatically. This aligns with modern research showing that prolonged dieting leads to adaptive thermogenesis, where the body burns fewer calories to conserve energy. This is why many people hit weight loss plateaus.

3. Psychological Impact of Restriction

The obsessive food thoughts seen in the study mirror what many chronic dieters experience. Restriction often leads to preoccupation with eating, binge cycles, and emotional distress.

4. Refeeding Requires Care

Just as the study participants struggled with recovery, people who have lost weight often regain it rapidly if they return to previous eating habits. This underscores the need for gradual, sustainable dietary changes rather than extreme cuts.

Conclusion: A Cautionary Tale

The Minnesota Starvation Experiment was a brutal but enlightening study that revealed the dangers of severe calorie restriction. While it was designed to help war victims, its findings remain relevant today, particularly in a world obsessed with rapid weight loss.

The key takeaway? Sustainable, moderate approaches to nutrition are far healthier than extreme dieting. The body resists starvation, and the mind suffers alongside it. For those looking to lose or maintain weight, the best strategy is balanced eating, patience, and avoiding the kind of deprivation that leads to long-term physical and mental harm.