The Minnesota Starvation Experiment - What we can learn

by Rebecca Haight and Lucas Serwinski

What is the Minnesota Starvation Experiment?

At the peak of World War II, hunger and starvation were running rampant in Europe. Up to that point, doctors and researchers relied solely on anecdotal reports when dealing with the effects of famine and starvation. Because there was very little scientific literature on the issue, they were not quite sure how to help people rehabilitate and recover from starvation.

In November of 1944, the newly founded Laboratory of Physiological Hygiene at the University of Minnesota launched a research study on the psychological and physiological effects of starvation. This study later became known as The Minnesota Starvation Experiment.

The study recruited volunteers from a pool of conscientious objectors, offering an alternative to military combat service. Over 200 ended up applying, eager to do meaningful work that would benefit humanity.

Thirty-six men were ultimately chosen – taking up residence in the rooms of the University of Minnesota football stadium.

How was the study conducted?

The course of the study lasted over a year, with protocol requiring the men to lose 25% of their normal body weight.

The experiment consisted of four phases, with differing dietary restrictions. Researchers measured the physiological and psychological changes brought on by the near starvation throughout.

Phase 1:

During the first three months of the experiment, participants were fed a normal diet of 3,200 calories a day and closely monitored.

Phase 2:

The initial three months were followed by six months of semi-starvation, where 1,570 calories a day were divided between breakfast and lunch.

Phase 3:

After the long semi-starvation period, a three month restricted rehabilitation began, moving participants back up to eating 2,000 to 3,200 calories a day. These calories were increased in increments.

Phase 4:

Finally, at the end of the experiment, participants underwent an eight-week unrestricted rehabilitation period during which there were no limits at all on caloric intake.

During the course of the entire experiment, the diet consisted of foods that were most available to Europeans during the war - mostly potatoes, root vegetables, bread and macaroni.

On top of the strict diet, participants were required to work 15 hours a week in the lab, walk 22 miles per week and participate in a variety of educational activities for 25 hours a week. All this additional activity meant, during the semi-starvation period, participants were expending over 1,000 calories more than they consumed each day.

Results of the Experiment

During the semi-starvation phase, especially, the physical and mental changes in participants were dramatic.

The men looked physically emaciated, with rips protruding and dark circles under their eyes. There were also significant decreases in their strength and stamina, body temperature, heart rate and sex drive.

Psychologically, the hunger made the men obsessed with food. They would dream and fantasize about food, read and talk about it constantly and excessively savor the two meals a day they were given.

The men reported feeling fatigued, irritable, depressed and apathetic, as well. They also reported decreases in mental ability, although mental testing of the men did not support this belief.

The study even proved too difficult for some men. In fact, data from three subjects were excluded as a result of their breaking the diet. And a fourth man was excluded for not meeting expected weight loss goals.

The Aftermath

The war ended on May 8, 1945, as participants of the Starvation Experiment were barely halfway through the starvation phase.

This meant relief efforts in Europe began far before results of the experiment were released. Experiment researchers and participants worried all the data they’d sacrificed so much to collect wouldn’t get to relief workers in time to help the starving people.

Eager to get information out quickly, members of the research staff prepared a 70-page booklet providing practical advice based on lessons learned in the lab. The book was titled, Men and Hunger: A Psychological Manual for Relief Workers.

Some of the tips included in the Men in Huger Booklet were:

• Show no favoritism and refrain from arguments. Those who are starving are ready to argue on little provocation, but they usually regret it immediately.
• Starvation increases the need for privacy and quiet - noise of all kinds seems to be very bothersome, especially during mealtimes.
• Energy is a commodity therefore living and eating quarters should be arranged conveniently, so as to leave the least amount of physical work up to the starving individuals.
• Starving people are emotionally affected by the weather - some special and cheerful activities are good to save for bad days.

The Minnesota Starvation Experiment ended in October of 1945. The University of Minnesota Press published the complete report of the experiment, entitled The Biology of Human Starvation, in 1950.

The key experiment finding was that the most reliable weight-gain strategy was high caloric intake.

Of all the various diets and supplements that were studied during the rehabilitation phase of the experiment, just plain food ended up being the key to rehabilitation.

Late in 1945, head researcher, Ancel Keys gave a speech discussing how best to re-feed malnourished people, saying: “Enough food must be supplied to allow tissues destroyed during starvation to be rebuilt … our experiments have shown that in an adult man no appreciable rehabilitation can take place on a diet of 2,000 calories a day. The proper level is more like 4,000 daily for some months. The character of the rehabilitation diet is important also, but unless calories are abundant, then extra proteins, vitamins, and minerals are of little value.”

To this day, it is still heavily cited as a source of reference by academics studying nutrition and eating disorders.

What this means for you

There has been a lot of dicussion in the fitness and nutrition community about having a "damaged metabolism".  This is the idea that going through periods of significant weight loss or gain will permanently damage your metabolism leaving you in an unrecoverable state.

What we know now is that metabolism is adaptive, not healthy or damaged.  In fact, the opposite of what most people think is usually the case in terms of metabolic rate.  Being larger regardless of body composition results in an INCREASE in metabolism.  And being smaller, even if you are very lean usually results in a decrease in metabolic rate. 

And physiologically, this makes sense: metabolic rate will rise as you gain weight in an effort by your body to burn more calories and bring your weight down to it's preferred set point.  And being small results in a lower metabolic rate so it is easier to gain weight back to your body's preferred set point.

The biggest confounder in this scenario are people who have been overweight for a very long time - often they will come to a nutrition coach like myself after trying a new diet or shake regimen and they will in fact be consuming a small number of calories without much change in weight.  But this is usually due to the calorie restricition being VERY short term when compared to how many years they have been overweight.  If you pull back to the 1,000 foot view, those small periods of calorie restriction are a blip on the radar compared to the periods of overeating.

And these severe, short term calorie restricitions almost always end in periods of bingeing which further reinforces the individuals higher body weight.  In my experience, this person thinks they have a broken or damaged metabolism but fail to see the cycle or account for how much food they truly consume when bingeing.  The answer usually lies coming back to the middle: sensible portions, eating a variety of foods and giving it TIME.  But these three factors are the hardest for many people.  So instead it's easier to latch onto the idea of having a damaged metabolism.

Lets throw one more wrench into the works: thinking that weight loss is stagnant because you aren't eating enough.  This can be a variable - women especially see some pretty dramatic resistance to weight loss with sever calorie restricition.  Leptin drops, N.E.A.T drops, motivation drops and basically you feel like crap. Plus any hormonal shifts like cortisol increases can make fat loss around the middle quite stubborn. If you combine this with a person who isn't eating much protein or fiber then we've got major issues.

The solution (yes, even for fat loss) is to increase protein, veggies and depending on the scenario, carbohydrates or fat.  Consider that the brain consumes 80-120g glucose per day all on it's own means I do not like people on very low carb diets, especially women. So again, coming back to the middle, allowing the fatigue and drain on the system to lessen and temporarily bringing calories UP, causes that metabolic adaptation to move in a positive direction.  Once a person is in a good place we can revisit lowering calories except this time not in a way that says "I hate my body".

One last note: sometimes when I increase a person's protein and vegetable intake they FEEL like they are eating more from a satiety and stomach fullness standpoint.  But this is one of the benefits of those food groups: how much they keep you feeling good while leaning out.  Often these people don't realize they are even in a calorie deficit because of how satisfied they feel incorporating the right foods.  So I'll hear "I ate MORE and lost weight".  In reality, more food volume, yes.  But not more calories.  Tricky tricky:)

The experiment above shows how the opposite end of the spectrum works.  Dieting down to even a dangerously low body weight can be reversed to a healthy normal state. But this takes time.  One giant meal isn't going to reset your metabolism.  And the psychological effects of being severely calorie restricted (or even being severly overweight) make this much more complex than calories in vs calories out. Considering they concluded that it would take months of not just adequate but abdundant calories to restore bodyweight should clue you in to how long this process takes.  And the same goes for losing weight.  If you need any practical proof, look at the Biggest Loser contestants.  Even those who have lost massive amounts of weight almost always rebound because the approach was so severe, short term and unsustainable.  Not only did their physiology not have time to properly adapt but their mindset and emotions needed more time as well.

Perhaps the hardest and longest term part of recovering from being severly underweight or overweight is the mind and emotions. Your body might be well along to a healthy place where your mind and self-image are stuck in the past.  The reason I advocate taking your FREAKING time (yes I am yelling this) is because people time and again fail or revert to their pre-diet weight due to their self-image and mentality. 

To drive this home, you will notice some of the key points (noted above) on the book written after the experiment all had to do with the participants mental and emotional state in regards to recovery.  Hmm, maybe we're onto someting?

Sources:

Baker, David, and Natacha Keramidas. “The Psychology of Hunger.” Monitor on Psychology, American Psychological Association, www.apa.org/monitor/2013/10/hunger.aspx.

Ball, Janet. “The Minnesota Starvation Experiment.” BBC News, BBC, 20 Jan. 2014, www.bbc.com/news/magazine-25782294.

Taylor, Rupert. “Minnesota Starvation Experiment.” Owlcation, Owlcation, 5 Sept. 2017, owlcation.com/humanities/Minnesota-Starvation-Experiment.