You're listening to Food is Food, the podcast that will support you to ditch diet culture, break free from food rules, and debunk nutrition misinformation. I'm your host, Talia Chiquelli, specialist eating disorder dietitian and founder of the TC Nutrition Clinic. If you would like to learn more about our one-to-one nutrition support and group program, or download your free portioning guide, head to wwwtaliachely.com. Each week we will cover topics that delve deeper into nutrition, intuitive eating, psychology, diet culture, and the consequences of under eating. Our relationship with food is so complex and it's influenced by our thoughts, emotions, and life experiences. Which is why healing from disordered eating is about more than just food. Welcome back to Food Is Food. A little disclaimer for you jump into today's episode. Just so you know, I do mention calories, weight, and some numbers specific to the findings from the starvation study. I do also talk about weight changes that occur as a result of undereating. I do not in any way want to deter you from nutritional rehabilitation or for you to be worried. The purpose of this episode is to give you hope that change can happen and symptoms are reversible. However, I just wanted to forewarn you if hearing about the science behind weight change, calories, or numbers might be triggering for you at the stage of recovery that you're in. Welcome back to Food is Food. Today we are going to be talking about the starvation or semi-starvation study. And to be honest, I'm not sure why people aren't talking more about phase four of this study. Being very vulnerable here, I didn't know about the fourth phase of this study until I was researching for this episode. And I have been a registered dietitian working in the eating disorder space for a decade, and it's like no one else knows about this phase of the study. So I cannot wait to get into that with you today. For those of you that aren't familiar with the semi-starvation or starvation study, it is also referred to online as the Ansel Keyes study or the Minnesota study. Now, being an evidence-based practitioner, I'm often looking for the most recent research when I think about evidence-based and ensuring that I am up to date. However, the semi-starvation study is one of those groundbreaking studies that you will hear many clinicians working in eating disorders still referring to because a lot of what we learnt about semi-starvation or malnutrition and the impact on the body comes from this landmark study. Ethically, you know, there's lots of complications as to how it can't be replicated in the same way these days. There have been further studies mostly in the armed forces and military where they have looked at the impacts of under-eating and semi-starvation. However, it's not to the extent or length of what happened during the semi-starvation study in 1944. So, for those of you that aren't familiar, this study took place during World War II. And during the time there were a lot of humans across the globe being faced with semi-starvation or starvation due to rations and also due to the famine experienced during the war. So Ansel Keys, who was the lead researcher, undertook an almost year-long study to look at the impact of semi-starvation and also how to safely refeed the population because this was really important due to what was happening around the world. So 36 young men ended up taking residence in the rooms of the University of Minnesota. That's where the study took place. These were all conscientious objectors, so men that didn't want to be engaged in the military service but still wanted to help with war efforts at the time. The average age of the men was 25, so quite young, ranging from 20 to 33. Really important to note they were all Caucasian males, and part of the criteria was that they had to be single and they had to demonstrate good physical and mental health. Now, part of the experiment was that these men had to lose 25% of their body weight during the semi-starvation period, so that was over six months. So I'm going to talk you through what the experiment was and looking at what the main findings were. The experiment was divided into four phases, not three, as I originally thought for so many years, and that's what I have been teaching my clients up until now, so I will be correcting that from now on. The first phase was the control period. So this was a 12-week period where basically the men underwent a whole bunch of studies, and they were all given a calorie-controlled diet, which averaged to approximately 3,200, 3,500 calories per day for the men. And this food mimicked the main foods that were available during European wartime. So their diet included mostly cabbage, potatoes, pasta, and minimal amounts of meat and dairy. And so during this time, it was really important for the men to maintain the weight that they entered the study, and they had to also engage in a certain amount of occupational or educational activities, about 25 hours per week, and they had to maintain a certain level of activity, which was 35 kilometers of walking per week, plush some additional time on the treadmill. During the control period, 12 weeks, they underwent a bunch of physical psychological tests so that that could be used as the baseline or control for the rest of the study. Phase two is what we call the semi-starvation period, and this took place over 24 weeks, so approximately six months. On day one of the semi-starvation phase of the experiment, the men's intake was cut by approximately 50%. So about 1600 calories, remembering that they were all on slightly different intakes because we're all humans, our energy requirements vary a little bit compared to one another. And each week the rate of weight loss was reviewed and their intake tweaked. So they were either given more food or less food to ensure that they were losing weight at approximately one kilo per week to achieve that 25% weight loss over the 24-week period. Now, this is where we see the huge impact of energy restriction over really a short period, long period. I I guess I can't really put a label to it, but over that six-month period, we learned a lot about how the human body reacts to receiving less energy than what it needs. So I'm going to go through the three main categories of changes that were observed over this time. The first is physical changes. So as you can expect with the degree of weight loss that these men experienced, the researchers saw a change in heart muscle, so a reduction in muscle mass of the heart. And this led to symptoms such as a low heart rate. The men experienced a decrease in their basal metabolic rate, so the amount of energy required at rest, and that was up to a 40% reduction by the end of the semi-starvation phase. They also experienced a decrease in their tolerance to cold weather. By the end of the study, they often were asking for extra blankets at nighttime. They experienced a lot of fatigue, hair loss, dry skin, increased hunger. The frequency of their bowel movements reduced to about once per week. Some of the men's face became puffy due to edema, so an increase in fluid being held by the body. They had difficulty sleeping. Some of the men experienced that they required less sleep. They experienced dizziness, 21% reduction in strength, and they felt old and tired all the time. So one of the men actually described that he, as part of the 35-kilometer walks, he would try to find ways to reduce his energy expenditure. So if he was on the road, he would try to find a driveway in order to walk up to the path rather than taking a step or over the gutter because that was really effortful. Next, I want to talk about the psychological changes. So the impact of semi-starvation had a huge influence on the psychological shifts for the men, including a decrease in alertness and focus. The men experienced impaired decision making. They found it hard to concentrate. There was an increase in obsessive thoughts and rigid thinking, and a lot of this increase in obsessive thoughts was regarding food. A couple of the men developed uh psychotic episodes. So one man, after only a few weeks of the study, was actually admitted into a psychiatric ward because he became quite angry towards Ansel Keys and threatened to take his own life. So he was dismissed from the study, entered a psychiatric ward, or was admitted to a psychiatric ward. And interestingly, after only a few days of being on a normal diet as a patient on the ward, his symptoms completely disappeared and he presented normally again, so was discharged, which is just fascinating the impact of that semi-starvation or dietary restriction, how instant it increased his mood and the emotional regulation. Throughout the semi-starvation period, many of the men did experience an increase in depression, dregulation, anxiety, and irritability. They also experienced isolation and withdrawal and a decrease in sex drive. That irritability also was seen within the group, not just with others. There was also a decrease in sense of humor, so just connecting back to that energy and lack of like zest for life. And that also impacted on relationships. So relationships became very strained due to that increase in irritability, depression, withdrawal, you know, reduced sense of humor and wanting to be around other humans. There was also a decline in personal hygiene. And some of the men started to dream about food, with one of the men sharing that he had dreamt that he'd eaten forbidden foods and actually reported feeling guilty when he woke up from that dream. And then we have the behavioral changes. So this specifically relates to sort of eating behaviors. So some of the men during this 24 weeks started to hoard and steal food. So a couple of the men were removed from the study because they broke the diet. One of the men was so tempted by food when he was out on one of his walks that he ended up going from sort of ice cream parlor, milk, milkshake bar, and having ice cream and milkshakes. And as a result, he was removed from the study. Another man was really tempted on his walk by the delicious smell of a bakery. And so he walked past and purchased a dozen donuts and gave them to children and watched them eat it. Sounds a little bit creepy, but this is what we see in clinic all the time is when someone is undernourished. I'm going to connect all of this back to what we see in eating disorders, but when someone is undernourished, they start to notice other people's eating behaviors and either get sort of turned off how other people eat or they can become fascinated by watching others eat. Some of the men also began obsessing over food and recipe books. Five men collected recipe books, with one man collecting over 100 books during the year. That is so many recipe books. Many of the men, about a third, reported distress about the waste of food, with one looking at food in bins as well. As I mentioned, there was this increase in pleasure watching others eat, and others couldn't stand watching other people or other volunteers in the study eat. Food became very central to the conversation, and some of the men became very possessive over their food. So they were worried that others would steal their meals and they would guard their food quite defensively with their elbows. So during this phase of the study, so the 24 weeks of semi-starvation, the men were getting two meals a day, so that European style food, one at 8 a.m. in the morning and the other in the evening. What was also observed is that the men developed strange eating behaviors. So some of the men would water down their food to try and make it last longer. Others started to add additional spices, some ate really rapidly, some people ate really slowly, and some started to lick their plates clean. So none of these behaviors were present at the beginning of the study. Interestingly, men also increased their coffee consumption. So some men were having up to 15 cups of coffee per day as a way of managing their high hunger levels. Other behaviors that were used to try to reduce the intensity of hunger were smoking. So four of the men started smoking during the semi-starvation period. And some of the men, so a handful, started to chew gum excessively, which was freely available at the beginning of the study. However, because one of one or some of the men were starting to consume high amounts, it was reported up to 40 to 60 packets per day. Ansel Keys ended up putting a cap on the amount of chewing gum that the men could have. So there were 36 men that entered the start of the study. Four men ended up being removed during that semi-starvation period because three broke the diet and one didn't achieve the weight loss goal. So after the 24 weeks, we then move into the rehabilitation phase or phase three. And this was a controlled phase of rehabilitation. So now we have 32 men, which were divided into four different groups, and they were each given different caloric amounts because Ansel Keys wanted to see just how much energy the human body needed in order to rehabilitate safely. And some of the men were prescribed vitamins and some were given some extra protein. Now at the beginning of the 12-week period, it didn't make any difference as to which calorie-controlled intake the men were on in terms of restoring the weight they lost and reversing these physical, psychological, and behavioral symptoms that had developed over the semi-starvation period. So what ended up actually happening was that Ansel Keys kept increasing the men's caloric intake to the point that by the end of that 12-week period, some of the men were on approximately 4,200 calories. So about what 500 to 1,000 calories, if I'm doing my maths correctly, compared to what they were on in that control period. Also really interesting during this rehabilitation phase is that none of the men returned to their control weight. So after 24 weeks of semi-starvation, 12 weeks of control or rehabilitation, sorry, none of them were able to return to that control weight. Now, what's really interesting if we just look at those three phases of the study and why this is such a landmark study in the context of an eating disorder or disordered eating is because so many of those physical, psychological, and behavioral changes that the men experienced, we see in the context of an eating disorder. So it's really important when we think about eating disorders as an illness that a lot of the behaviors that are presenting are not because of the eating disorder itself, but typically they're a result of a person just not having enough energy. So when the human body isn't getting enough energy, all of those body systems are going to downregulate, and that's going to have an impact on both the physical and psychological functioning. Just like the men experienced low heart rate, poor digestion, feeling cold all the time, that psychological changes, feeling irritable, not able to concentrate, socially withdrawing. These are all traits that develop as part of the body being undernourished. None of these men had an eating disorder. Part of the criteria was they had to be in good physical and mental health. So none had disordered eating or an eating disorder at the beginning of the study. And yet what they presented was what we see in eating disorders such as anorexia and bulimia nervosa or in disordered eating. And the behavioral aspect as well. We see eating behavior change in eating disorder presentations. People cutting food into tiny pieces, people are eating food in a particular order on their plate. Some eat really slow to try to space out the meal, others eat really quickly to get it over with. We see people excessively use condiments quite often, adding more salt and chili and herbs and spices to their food. And we see people take away all of the condiments from the food that they're eating. These can all be connected to undernutrition rather than it being part of the eating disorder. And this is why this study is so incredibly helpful for people to understand the impact of undernutrition and under-eating. Now let's move on to phase four. So this was the new phase that I'm being very vulnerable here. I did not know about until a few days ago. So after the almost year-long study, so those 12 weeks of controlled rehabilitation, Ansel Keys actually convinced 12 men to stay in the study for a further eight weeks. And this was an unrestricted period where the men were able to eat an amount of food that they wanted. Now, this is where it's really important in the context of overcoming undereating or restrictive eating. So when the men were allowed to eat in an unrestricted way, the amount of energy that they consumed increased to approximately 4,500 to 5,000 calories per day on average, with some of the men consuming up to 7,000 to 11,000 calories on a single day. Now, after some time, unfortunately, Ansel Keys did put a limit on the volume of food that the men were eating because he was worried. However, even just that initial period tells us a lot about how the human body works and how it's programmed to increase hunger levels and return to that baseline or control in terms of body mass, fat mass, muscle mass. So for many months, the men reported having this sensation of hunger that they just could not satisfy, no matter how much they ate. And what the researchers are calling this intense sort of hunger is compensatory hypagia. And I love that word, compensatory hyperphagia. So compensatory hyperphagia is an intense adaptive increase to the intake of food that occurs to counteract calorie loss or restore energy balance after starvation, fasting, or maybe specific medical treatments. So this is what the men were experiencing when they were, you know, when that lid was lifted, the gate was opened, and they were allowed to eat whatever their body was communicating that they needed. So they experienced this compensatory hypophagia. So this short-term adaptation of increased hunger levels to increase food intake. Now, what's even more interesting is that we started to observe behaviors that are very closely aligned with bulimia nervosa and binge eating disorder. So of those 12 men, two engaged in purging behaviors on a couple of occasions. One of the men had to go to hospital and get his stomach pumped because he ate too much in one sitting. And of all of the men during both phase three and phase four, 10 experienced overeating, and six engaged in what we would classify as binge eating behaviors. And that is just so interesting. Again, it highlights that as part of the behaviors that we see in eating disorders, they can be closely linked to under eating rather than it being driven by another factor such as maybe emotional dysregulation or as a coping mechanism. So we we have to always think about is this being driven by under eating and ruling that out? As a factor. Now, in terms of follow-up, so after phase three of the study, 21 of the males were re-evaluated after eight months of rehabilitation, and then eight were re-evaluated at one year. And in 2002, 2003, there were two really fantastic studies that came out where the participants who were still on this earth in their 70s and 80s by that stage were interviewed again. So 18 in one study and 19 participants in another study were interviewed. And the original research was re-evaluated. And the purpose of this research was to, I guess like the overall question was to see if there were any long-lasting physical or psychological side effects that the men experienced. To give you the short answer, no. However, what the men did share is that it took anywhere from six months to five years for eating behaviors and weight to return to normal. So some of the men experienced what we call overshoot, where during that rehabilitation period, where there were no restrictions on the amount of food that they were eating, both when they returned to home as well, their weight ended up restoring above that control weight or when they first started the study. So the mean average of that overshoot, so weight gain above that control weight, was 3.3 kilos. However, that's the mean on one end of the range. There was reported to be about 116% increase above the control weight. So just to spit out some numbers, so the men that were part of this study were below the average weight of American men at the time. So just to give you an example, if one of the men was 70 kilograms at the start of the study, then that 116% would take him up to 81 kilograms as part of that rehabilitation and the body restoring towards baseline again. Interestingly, three of the men never returned to their pre-study weight, so they did stay at higher weight. And one of the other findings from this review of the study and interviews with the men is that in terms of returning to a healthy weight, it wasn't impacted by the distribution of different macronutrients. What they observed was that energy alone is what the body needed in order to restore those physical, psychological, and behavioral side effects or symptoms that the men experienced. So why this study is important is because it really gives us an insight into the physical, cognitive, and behavioral changes that occur as a result of under-eating. It also gives us beautiful insight into the impact on hunger and how hunger following a period of restriction can lead to a person engaging in behaviors such as overeating, binge eating, or even purging. And also it gives us really wonderful evidence of how the human body is built to survive and to come out of a period of semi-starvation or under eating, in that how some human bodies restore and return to full physical health. So through nutritional rehabilitation, and what I'm referring to here is the body returning back to a healthy one for that person, is that for some people that happens quickly within a matter of months when they are meeting their nutritional needs. For others, it can take many years in order to get there. And this really just highlights the individuality of a person's experience. Similarly, with how that weight change occurs, is that some people will return to their healthy weight. Others will need to go through a period of quote-unquote overshoot where they restore above their previous weight in order to overcome that period of under eating. And for some, it might be that they end up restoring to a bit above where they were previously, because biologically that's where their genetics have been programmed in order to be healthy and safe following a period of undereating. And what's really interesting in terms of body composition changes during weight restoration is that for some people, and this was showed in the starvation study, is that during that restoration period or rehabilitation period, the men restored fat mass quicker than fat-free mass. And I'm going to have to do a whole nother podcast on the science behind weight changes and weight restoration because it deserves its own podcast. But I will just say that it's really interesting what we see in the study and also in more recent research that has come out is how the body prioritizes fat mass in terms of restoring that versus fat-free mass. And this is where the overshoot theory comes in is that for some people, just how they're genetically programmed, if they have gone through a period of undereating and weight loss, they may need to restore fat mass to a certain degree, and then they will build muscle mass, and then the fat mass reduces back towards normal again. And this is very typical in what we see in eating disorders and the sort of concept or theory of weight redistribution, where some people will experience sort of more fat being stored around their abdominal regions, protecting those internal organs, and with time that fat being used by the body and the fat being redistributed or used by the body, and therefore weight settling back towards where it was previously, or what is the new sort of healthy for someone. I promise you I would do an episode on what is a healthy weight, what is the science behind weight change. But for now, I hope that just having an understanding of the impact of under-eating on the human body and some of those key behaviors that we see in eating disorders has given you a different insight or angle to view where some of these behaviors may be coming from. And also giving you hope that through nutritional rehabilitation, eating adequately, those behaviours that have been influenced by under-eating, whether it be physical changes, psychological, andor eating behaviors, will improve and reverse through adequate nutrition. Thank you so much for listening today, and I'll catch you next week. Thank you for tuning in to Food Is Food. If you found the episode nourishing, hit subscribe so you don't miss our weekly episodes. And just before we wrap up, a little reminder that the discussions in each episode are for informational purposes and don't replace individualized advice. Because every recovery journey is so unique. Please consult your healthcare provider for support. That's all for today. Stay nourished and see you next time.