One of the first scientific studies on what hunger does to the mind was observed in a study remembered as the Minnesota Starvation Experiment performed by the University of Minnesota back in 1944. The lead investigator was Ancel Keys who had two Ph.D. one in biology and one from psychology. Thirty-six men were selected that were healthy and had no eating disorders from hundreds that volunteered.

Minnesota starvation experiment was a study where the goal was to live on a diet of 1500 calories for six months. In the first 12 weeks, there was a 3200-calorie control period, and then a real experiment started. Now 1500 calories are far from real starvation. The American government wanted to understand what psychological and physiological effects are going to be on war-torn Europe with starvation and the holocaust. There was no industrial or direct military interest in this. It was done as a defense interest project because no one has done anything similar in the past and there was a real concern about the behavior of people that have been exposed to terror and starvation. There was a concern that people that have been released from concentration camps and that have gone through starvation on the battlefront might pose a threat to society. Also, the government wanted to have a guide for rehabilitating those who were starving.

Men were housed in a basement of the Minnesota University Stadium in windowless rooms with a program of mental and physical exercises. Diet was strictly controlled, and they could not cheat because they were in some sense incarcerated for six months. The scientist initially didn’t think of this experiment as a behavioral experiment in terms of evolutional psychology. The experiment without their initial realization reconstructed the conditions of habitat that existed during the evolution of the human species. An environment of scarcity. Starvation and survival of the fittest. This was an environment that was similar to most of human evolution and as such was more normal than our current environment. It was an environment in which our brain evolved and was designed to cope with. Normal conditions of our current abundance of food were in an essence unnatural. The behavior and hunger in an environment of scarcity with a high death rate were the groundwork for understanding what drives our instincts and how strong those instincts are.

On a calorie restriction of 1500 calories after some initial period subjects started to lose weight and by the end of the study, they lost a significant number of pounds. What was more important is that the experiment did show significant behavioral changes. Starvation did have psychological effects on them.

In the beginning, they started to be apathetic and irritated and they developed ritualized eating patterns. Putting water into potatoes to make them bigger. Holding the food in the mouth and chewing for an extended period. Licking the plates. Daydreams of food, chewing gum, and smoking cigarettes until someone had 30 packs per day. Drinking a ton of water to fill their stomachs. Then they started to enjoy solitary activities and looked at food in a sexual manner. They had no regular sex drive and were only interested in what people ate. They developed an eating disorder mentality. They started to feel bad about themselves if they binge and felt guilty about food. What they considered normal weight before, during the study was considered to be overweight. When they look at their old pictures, they thought they have big stomachs and much more weight than what will in that situation for them be a normal human physique. They experienced confusion when they are hungry and also when they are not.

This is an extract from one of the volunteer’s diaries:

“I am beginning to isolate myself from other subjects. We are developing all kinds of weird behaviors. Everyone seems to be losing their interpersonal skills and starvation is less than half over. One of them bit the other volunteers. Many tried to escape from the compound to eat grass from nearby gardens. Another became so deranged that he chopped three of his fingers off with an ax.”

Later the ax men stated that he was “messed up” and that he could not remember why or how he chopped his fingers, and he could not say that he did not do it on purpose. This is what a strict diet of 1500 calories did to this person in less than six months.

In cases of hunger, human behavior was shifted to survival mode. Nothing was important except for food. They didn’t care about moral and social norms and didn’t care about sex. They have completely emerged into existentialism that any external input that didn’t have a direct effect on their survival was of less importance to them. Aggressive behavior was avoided only because there was no chance of escaping and because of legal consequences. They were locked in underground “prison” in the stadium and had very little chance of physically escaping. The scientist predicted this and was strict in subject selection. Before they were chosen to be part of the experiment subjects had to show an ability to get along well with others under trying circumstances and had to have an interest in relief work. They selected nice young men with a good moral compass that had no psychological disorders before the experiment.

What happened after the experiment is even more important. 

When they started to feed on their own wish there was something entirely unexpected. They rapidly put on weight but not only that. They gained more than what they had at the starting point. Dieting made them fatter. They experienced something called extreme hunger. They ate and ate and ate and ate and never felt satisfied. Most companies in the diet industry and medical care know about this.

Dieting can make you fatter. Fear of starvation is real. Psychophysical dependence on supernormal stimuli is real. Human beings are evolutionarily conditioned for extreme eating because of the scarcity in nature.

Keys published “The Biology of Human Starvation” in 1950, which describes the impact of long-term food deprivation on human physiology and behavior. The Minnesota Starvation Experiment’s legacy, however, is the impact it has had on research into the effects of food deprivation in those with eating disorders (9).

Minnesota starvation experiment in later years became a base for an understanding of human psychology. Most of the scientists that work for the food industry know about the Minnesota starvation experiment very well. It is a well-known fact from that period onward that dieting does not work. After the Minnesota starvation experiment, the term “yo-yo” dieting was coined. Everyone that sells diets and supplements, diet plans, and books, all of the scientists in the labs of big food companies knows about this experiment. It was one of the ground-breaking experiments that build a foundation of nutritional science. Food companies, for example, will promote food that is supernormal stimuli (a combination of fat and sugar at the same meal) to the children knowing that once when the brain adapts to that stimulation they will be addicted for life.

The way that we are conditioned to behave is the number one avoidance of pain. When pain is avoided pleasure-seeking comes into play. Because of a self-preservation mechanism our brain works by the “carrot and a stick” mechanism. Avoidance of pain is the foundation of individual behavior. Until the pain is removed the pleasure-seeking does not exist and is redundant. People can lose their entire identity and their entire self-controlling mechanisms when forced to be in a state of extreme hunger. We are not in charge.

Psychologists were well aware of this even before the Minnesota starvation experiment. But what was a real discovery is that the fear of starvation never, in reality, went away.

Today there is a wide range of clinical experiments have been done. At the University of Gothenburg in recent years, there was a line of studies but in all cases the conclusion was similar. Ghrelin, the “hunger hormone”, was found for example to directly effects the ventral tegmental area, the part of the brain that is a crucial component of the reward system. Ghrelin injections in rats also caused changes in dopamine-related genes and enzymes (controlling the reward and pleasure centers of the brain) and were also found to make rats more impulsive (1).

Millions of years of evolution have conditioned our behavior and in a normal natural environment is an evolutionary protective mechanism. In our modern technology-driven environment without scarcity self-controlling mechanisms don’t really work.

I always like to give a comparison with drowning. If we want to commit suicide by holding our breath, for example, we will not be able to. Sooner or later our brain will override our behavior and will gasp for air. It detects pain and it is in a state of dying one way or the other so there is nothing to lose anyway. This is a reason people always drown and do not suffocate. The same story is with food or water. People will overeat because they can. Any type of dieting will make things even worse in the long run. Even if we try to lose weight we are going to be in a constant struggle against our conditioning. And even if we do prevail, it is not possible to be in a state of hunger and enjoy life. Especially because now we are removed from our natural environment and we have supernormal stimuli everywhere. Even a normal feeling of hunger is something that we cannot take as a normal feeling anymore.

Sources:

Passages selected from a book: “Go Vegan? Review of Science: Part 1” [Milos Pokimica]

1. The Stomach-Derived Hormone Ghrelin Increases Impulsive Behavior. doi: 10.1038/npp.2015.297
2. They starved so that others be better fed: Remembering Ancel Keys and the Minnesota Experiment. J Nutr. 2005 Jun;135(6):1347-52.
3. The biology of human starvation, (Vols. 1–2). Minneapolis, MN: University of Minnesota Press. Keys, A., Brozek, J., Henshel, A., Mickelson, O., & Taylor, H.L. (1950).
4. From Belly to Brain: Targeting the Ghrelin Receptor in Appetite and Food Intake Regulation. DOI: 10.3390/ijms18020273 
5. Metabolic adaptation to caloric restriction and subsequent refeeding: the Minnesota Starvation Experiment revisited doi: 10.3945/ajcn.115.109173.
6. Physiology of weight regain: Lessons from the classic Minnesota Starvation Experiment on human body composition regulation doi: 10.1111/obr.13189. 
7. The effects of partial starvation on somatotype: an analysis of material from the Minnesota starving experiment doi: 10.1002/ajpa.1330050305.
8. Autoregulation of body composition during weight recovery in human: the Minnesota Experiment revisited PMID: 8696417
9. Keys et al. (1950) “The Biology of Human Starvation (2 volumes)”. University of Minnesota Press.

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