I miss the good old days where research ethics weren’t so stringent, and we could run experiments more freely to learn about psychology and physiology. Think of all the cool stuff we could study if “human rights” didn’t stand in the way. I kid- thank goodness for research ethics, but they do prevent lots of studies that could yield fascinating results.
Fortunately, the study we are talking about today occurred in 1944-1945, long before research standards became increasingly stringent, allowing researchers to put volunteers in semi-starvation mode for 6 months. Unfortunately, but also fortunately, I don’t foresee anyone getting clearance to conduct a study of this nature these days, but there were follow up interviews with some of the participants in 2002, 57 years later.
We’re going to do a deep dive in The Minnesota Starvation Experiment because it remains the most comprehensive study on the effects starvation can have on a human being. The data from this study shows the toll food restriction can take on us, both in the short and long term, and it directly relates to the diet culture we have in this country.
I learned about this experiment briefly in undergrad, and I have had a ridiculously fun time digging deep and learning everything I can about it for this article. It has some dark origins and effects, but it’s well worth discussing.
Why Starve Men on The University of Minnesota Campus?
While WWII raged on, starvation and hunger was also running rampant around the world. The purpose of this experiment was to learn the psychological and physiological effects of starvation and how to devise a protocol for reintroducing food to those stuffing from malnutrition.
Reintroducing food to a person that has been starving for a length of time can be tricky because, to keep it simple, the body won’t be able to digest and metabolize large amounts of food properly anymore. If one were to spend months in a malnourished state and suddenly hit up a buffet every day and eat large amounts of food like I do at HuHot, it could lead to horrible consequences.
Those consequences are now collectively referred to as Refeeding Syndrome, and this term actually came about after WWII concluded. When starved prisoners of war were released and fed again, many of them began showing symptoms like fluid retention (edema), difficulty breathing (dyspnoea), and heart failure.
It’s a serious condition, and many of them died from these complications. Refeeding Syndrome is still a concern for those battling anorexia, alcoholism, or a variety of other conditions correlated with malnutrition.
Starting in 1944 and ending in 1945, 36 white men (per usual, am I right?), aged 22-33, volunteered to live on the University of Minnesota campus for a whole year. There were over 400 applicants, thanks to a tragic call-to-action flyer with a little kids and empty bowls saying “will you starve so that they be better fed?”
Of the 400 that were considered, 36 men were chosen based on their favorable physical health, sound mental health (determined by the Minnesota Multiphasic Personality Inventory), normal weight status, being unmarried, the ability to get along with others in stressful situations, and a desire to participate in rehabilitation work.
In the first phase of the study, participants were given a customized meal plan of adequate calories to get them to their ideal body weight, taking physical activity into account.
During the next phase, semi-starvation, the men were given a diet that would get the men to 25% of their ideal body weight. In this phase, their diets mimicked what one would find in European countries devastated by war, like potatoes, rutabagas, turnips, noodles, and dark bread.
Their calorie allowances were divided into two meals per day, breakfast and dinner, except for Sundays. They had a slightly larger meal for lunch on Sundays, so I can imagine they looked forward to that day as much as I look forward to Greek takeout.
The amount of calories each man was given depended on how close they were to their 25% weight loss goal, and researchers adjusted their meals by changing the amount of bread each man received.
Next, the men were put through a three month guided rehabilitation stage, and they were divided into 4 groups to see how different calorie amounts and dietary factors would impact recovery. After these three months, the men were allowed to eat a “semi-unrestricted” diet, meaning they had portioned meals during the week and no restrictions on the weekends. After this phase ended, most men left the study, but 12 stayed and were monitored during a two month unrestricted phase.
While this study went on, the participants stayed busy by being enrolled in classes, working 15 hours per week, and by walking at least 22/miles and 30 minutes at 10% grade on a treadmill each week for their required exercise. Aside from living in the dorm, eating meals together, and the above requirements, the men were able to socialize and participate in other activities freely.
The Effects of Semi-Starvation
After the boring control portion of the study, the semi-starvation phase is where things really started to get interesting. Not long after beginning this phase, the men became obsessed with food- they talked about it constantly, played with it on their plates, collected recipes, and adopted bizarre behaviors to deal with hunger (we’ll talk about this more later). Some even reported dreaming about foods that were forbidden, and they woke up feeling intense guilt.
Physically, the participants became lethargic and felt dizzy upon standing, sometimes blacking out. The men also peed a lot more, throughout the whole day and night, which sounds exhausting. Their hair started growing much more slowly, and it began falling out at a higher rate.
The participants became increasingly cold to the touch as they continued to lose weight and fat stores. They spent a good chunk of their free time laying in the sun, trying to warm up like a reptile on a rock. They requested their meals to be super hot, and they frequently wanted hot baths.
Ten of the men began pounding coffee and water back to stave off hunger, distract themselves, and keep warm too. Some began consuming up to 15 cups of coffee per day, but problems arose from the caffeine intake. The researchers had to implement a 9 cup limit per day on coffee, which still seems like a lot of caffeine to me, as my hands start shaking after two.
Fourteen men started chewing substantial amounts of gum every day. One of these gum-chewers chewed 40-60 packs of gum per day. Limits of 2 packs per day had to be put into place because this particular participant developed mouth ulcers from chewing that much gum. Beyond that, four of the men took up smoking cigs.
These behaviors and compulsions were a sign that their nutritional needs were just plain not being met. Some places on the internet actually recommend drinking tons of water or coffee and chewing gum to help you maintain your low calorie goals, but they can also be a symptom of inadequacy. Back in the day, smoking was also advertised as a way to lose weight too, but most of us know that isn’t advisable today.
Researchers evaluated the men’s mental health frequently throughout the study. In the semi-starvation phase, each and every participant scored higher on depression, hypochondriasis, and hysteria. This phenomenon was labeled “semi-starvation” neurosis.
Five participants showed symptoms that became more serious than “semi-starvation neurosis”, and two men had to go to the hospital because of “pre-psychotic” symptoms. One participant experienced cyclic episodes and plunged into what he called a “deep, dark depression” for weeks. He began to recover in the rehabilitation phase.
Other men experienced major highs and deep lows too. One man, who was later disqualified due to not adhering to the restrictions, went wild on purchasing food in town during the experiment. He later described a euphoric feeling of freedom and he stated that lights seemed brighter and life seemed better. Afterwards, he felt intense guilt about what he had done and for not being able to stick to the diet. Can you relate to the elation when eating “forbidden” foods, only to feel guilt and self-hatred later?
One participant described strange dreams of “eating senile and insane people.” His MMPI score showed that he displayed similar symptoms to someone with diagnosed schizoaffective psychosis. He actually stole candy and other goods, breaking the diet restrictions while diligently hiding it. He began making suicidal threats and displayed violent outbursts, eventually getting dismissed from the study and taken to a psychiatric facility.
Another man began rooting through garbage cans. He started eating garbage, but he was dropped from the experiment because he didn’t meet the weight loss requirement. After he was dismissed, he compulsively overate and admitted himself to a psychiatric ward.
Yet another participant chopped off three of his fingers and had to be sent to the hospital. He luckily made a quick recovery, and he was able to finish out the study. In a later follow-up, he stated that he wasn’t ready to say whether or not he did it on purpose.
All of this stuff is mind-blowing and heart-breaking, but for some reason, the fact that one participant was unable to maintain a relationship with a girl he had fallen in love with during the control period of the study made me so sad. He could feel that he wasn’t himself during the semi-starvation phase, and he described feeling like it was so much effort to spend time with her, even to hold her hand. He wanted to isolate himself instead, and he was having a hard time keeping it together with her.
Have food restrictions ever made you feel like you wanted to withdraw from society? Have they ever made it difficult to maintain relationships with significant others, friends, or family? Maybe at the time it didn’t feel like it was a diet’s fault, but it very well could have been. The word “hangry” exists for a reason, people.
Perhaps these examples from the study seem like extreme cases to you, but I think this experiment does an excellent job of showing the less-than-ideal effects food restriction and semi-starvation can have on a person’s body and mind. Again, these men had sound physical and mental health at the beginning of the study, and all of these problems were brought on by being in starvation mode.
We may not experience symptoms as severe as these participants, but we have to know that we don’t feel like ourselves when we reduce our intake for long periods of time. Maybe we become more irritable, fatigued, dizzy, and we start having major mood swings. Or, perhaps we start drinking unhealthy amounts of liquids or chewing tons of gum to cope with the hunger pangs.
Maybe we obsess over the foods we are avoiding, and have hangry outbursts at our loved ones. From my perspective, life is much too short to spend any amount of time experiencing even a mild version of these symptoms in the name of potential weight loss (that probably won’t stay off, anyway #dietsdontwork).
Rehabilitation and Unrestricted Phases
After the six months of grueling semi-starvation, the participants entered the three month rehabilitation phase in four different calorie groups. The group that received the fewest calories in this phase ended up having the highest depression scores, and the group that received the highest calories had the lowest depression scores according to their MMPIs. Eventually, all of the participants returned to their baseline for depression once their eating patterns normalized again.
Throughout the rehabilitation phase, seven of the men were preoccupied with the weight they were gaining and how “fat” they felt. Some men were even bothered by how “overweight” they felt the researchers were during semi-starvation.
Next came the unrestricted phase, and participants on average ate 10,000-11,000 calories per day. The research team then had to reinstate some portion control to avoid health consequences, so their policy became that weekdays had mild restrictions and weekends were unrestricted. Most participants began eating 50-200% more on the weekends when they were free from restrictions.
By the 33rd week of rehabilitation/unrestriction, the participants weighed, on average, 14% more than they did at the beginning of this study. Beyond this, the men had 40% more fat than at the beginning of the study.
Weighing 14% more and having 40% more fat aren’t necessarily a problem in my eyes, but these numbers show how long term restriction ends up having the exact opposite effect that dieters want it to. After nine weeks of the rehabilitation phase, the men were at their highest weights and fat mass levels.
To the dismay of many chronic dieters, the body prioritizes fat storages first after starvation mode. Bodies, understandably, freak out after being starved, or simply restricted, for an extended period of time, so they try to build up their stores when possible and hold on to everything they can.
Once a body is properly nourished for a long enough time, the body can start to shift toward building muscle. It’s almost as if your body is building up enough trust in you to not deprive it again, so it can relax and work on lean tissue for you.
When people come off diets and see that they’re starting to gain back mostly fat, many feel defeated and decide to restrict again. They get stuck in a cycle of this happening over and over again, and that’s how the diet industry makes profits off us year after year. If you are trying to break the dieting cycle, keep this in mind when you feel yourself start to want to restrict again and keep your sights set on repairing your relationship with food and your body, not your weight or body fat percentage.
It takes time and patience to find intuitive eating and get ourselves to a point where we never have to feel the need to restrict again. We have to learn to trust our bodies, and our bodies will have to learn to trust us again, and the damage from years of chronic dieting can’t be undone in a few weeks.
In fact, it took 18 months for the participants from this study to return to normal eating habits. Some men didn’t take long at all, and some took one to four years to return. This was only after 6 months of semi-starvation, not even years of diet cycling.
Fortunately, the follow-up evaluation showed that physical, emotional, and congnitive changes in the semi-starvation period were temporary, only lasting until intake levels returned to normal, which again, varied for everyone. The first signs of recovery was a decrease in dizziness, apathy, and lethargy. Improved libido and strength came back more slowly. One man said he knew he had finally recovered when his sense of humor had returned.
Why Talk About This Study?
The Minnesota Starvation Experiment shows that food and calorie restriction can really mess with our minds and bodies, and diets can give people the exact opposite of what they’re striving for. This encourages many to just end up on another diet and move further and further from intuitive eating.
There were so many instances where I could relate to the experiences the men had while I was trying to reduce my intake in the past. I felt relieved to know that I’m not the only one who has become irritable or withdrawn because of food restrictions. People don’t typically talk about how awful diets can make us feel, they only focus on the amount of weight they have lost or want to lose.
This experiment can teach us plenty, but there are important differences between it and those experiencing disordered eating or actual prisoners of war, of course. For starters, participants described feeling mostly safe during the experiment, and they knew the exact date their semi-starvation phase would end. This clearly cannot be said about those who struggle with disordered eating or those who have been starving for other reasons.
Even still, knowing more about this study can provide key insights into the biology and physiology of semi-starvation, and it can help people see the negative consequences reduced intake can have on everyday life.
I hope you found this Minnesota Starvation Experiment deep dive worthwhile! If you want to learn even more about it, check out my sources below:
- The Psychology of Hunger
- They Starved So That Others Be Better Fed: Remembering Ancel Keys and the Minnesota Experiment
- What We Can Learn from the Minnesota Starvation Study About the Impact of Restriction on Behavior
- A 57-Year Follow-Up Investigation and Review of Minnesota Study on Human Starvation and Its Relevance to Eating Disorders (PDF Download)
- Real Health Radio Podcast – The Minnesota Starvation Experiment
- Real Health Radio Podcast – The Minnesota Starvation Experiment Follow Up
As Always, A Book Recommendation
This week, the fourth edition of Intuitive Eating was released! Intuitive Eating is the very book that really got me, and countless others, off the diet culture bandwagon and onto the food freedom one.
If you find yourself still struggling with the diet cycles we talked about with this study, I highly encourage you to read the newest version a try to either get started on your intuitive eating journey, or help you along on your existing one.
You can also get third edition’s audiobook (or any other available audiobooks) for FREE if you sign up for a free 30-day trial of Audible! If you already have Amazon Prime, you get TWO FREE audiobooks with this offer.
If you don’t yet have Amazon Prime, here is a free 30-day trial of Amazon Prime that will allow you to get free 2-day shipping and the ability to borrow Kindle books! What’s not to love?
As an Amazon Associate, I earn a small percent off qualifying purchases from products linked on my website. It costs you nothing, but it helps keep my website running. I only recommend things I genuinely love. Thanks!
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