The Minnesota [Semi] Starvation Study

[Tatyana]

Introduction

The biological reality of our weights and weight control, and the effects of dieting, were clinically demonstrated more than 50 years ago in what remains the definitive research on the subject. The findings in this famous study, revolutionary at the time, have been replicated in the most precise, complicated metabolic studies of food intake behavior, energy expenditure and the biochemistry of fat conducted by the country’s top obesity researchers.

This classic study made the most important contributions to our understanding of dieting, yet surprisingly few consumers today have ever heard of it. It was led by one of the world’s most renowned scientists, Ancel Benjamin Keys, Ph.D., popularly known for inventing K-rations — those indestructible transportable foodstuffs of white crackers, greasy sausage, chocolate and candy — that kept our soldiers alive during World War II.

In the 1940s, when starvation was widespread throughout war-torn Europe, little was known about the effects of human starvation or how to best refeed people who’d suffered from such deprivations. Dr. Keys led the first scientific study of calorie restrictions, at the Laboratory of Physiological Hygiene at the University of Minnesota, for the War Department. The researchers wanted to understand the medical needs facing millions of starving war victims and how best to renourish and rehabilitate them to health after the war. Their study was known as the Minnesota Starvation Study and the results were published in the legendary two-volume, Biology of Human Starvation (Minneapolis: University of Minneapolis, 1950).

The study itself was so comprehensive and intense, however, that even Dr. Keys admitted no other human experiment quite like it will ever be done again because, given what we now know, it would be seen as too cruel and life-threatening. While the degree of suffering the participants underwent would violate what is seen as the ethical rights for human research subjects today, in one respect this study was different from obesity and weight loss research done today. These men were not volunteering because they felt they needed to lose weight for fear that their own lives were endangered, nor were the study authors motivated by personal gain or selling a weight loss program.

The experiment — the starvation syndrome

The 40 young male participants were carefully selected among hundreds of volunteers for being especially psychologically and socially well-adjusted, good-humored, motivated, well-educated, active and healthy.

They were put on calorie-restrictive diets of about 1,600 calorie/day, meant to reflect that experienced in war-torn regions, for 3 months. They dieted to lose 2.5 pounds a week to lose 25% of their natural body weight. The calories were more generous than many weight loss diets prescribe today!

What this study was actually studying, of course, was dieting and restrictive eating — our bodies can’t tell the difference if they’re being semi-starved involuntarily like war victims or voluntarily. During the 3-month nutritional rehabilitation period after the diet, the men were randomly assigned to various nutritional regimens, with differing levels of calories, proteins and vitamins. The men lived at the lab and everything they ate and did was closely monitored, as was their health with a battery of tests. Daily exercise was walking about 3 miles a day.


As the men lost weight, their physical endurance dropped by half, their strength about 10%, and their reflexes became sluggish — with the men initially the most fit showing the greatest deterioration, according to Dr. Keys. The men’s resting metabolic rates declined by 40%, their heart volume shrank about 20%, their pulses slowed and their body temperatures dropped.

They complained of feeling cold, tired and hungry; having trouble concentrating; of impaired judgment and comprehension; dizzy spells; visual disturbances; ringing in their ears; tingling and numbing of their extremities; stomach aches, body aches and headaches; trouble sleeping; hair thinning; and their skin growing dry and thin. Their sexual function and testes size were reduced and they lost all interest in sex. They had every physical indication of accelerated aging.


But the psychological changes that were brought on by dieting, even among these robust men with only moderate calorie restrictions, were the most profound and unexpected.

So much so that Dr. Keys called it “semistarvation neurosis.” The men became nervous, anxious, apathetic, withdrawn, impatient, self-critical with distorted body images and even feeling overweight, moody, emotional and depressed. A few even mutilated themselves, one chopping off three fingers in stress. They lost their ambition and feelings of adequacy, and their cultural and academic interests narrowed.

They neglected their appearance, became loners and their social and family relationships suffered. They lost their senses of humor, love and compassion. Instead, they became obsessed with food, thinking, talking and reading about it constantly; developed weird eating rituals; began hoarding things; consumed vast amounts of coffee and tea; and chewed gum incessantly (as many as 40 packages a day). Binge eating episodes also became a problem as some of the men were unable to continue to restrict their eating in their hunger.

The aftermath

The last part of the Minnesota Starvation Study revealed perhaps the most important effects. When the men were allowed to eat ad libitum again, they had insatiable appetites, yet never felt full. Even five months later, some continued to have dysfunctional eating, although most were finally regaining some normalization of their eating. As they regained their weights, their suppressed metabolism and energy levels returned, although even three months after ending the diet none of the men had yet regained their former physical capacity, noted Dr. Keys.

While it seemed the men were “overeating,” Dr. Keys discovered that their bodies actually needed inordinate amount of calories for their tissues 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 kcal 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


In other words, they weren’t really “overeating,” it was a biological, normal effect of hunger and weight loss. The men regained their original weights plus 10%. The regained weight was disproportionally fat, and their lean body mass recovered much more slowly.

With unlimited food and unrestricted eating, their weights plateaued and finally, about 9 months later, most had naturally returned to their initial weights without trying — giving scientists one of the first demonstrations that each body has a natural, genetic set point, whether it be fat or thin.

Despite the fear that with unrestrained eating everyone would continue to grow larger, it isn't true.


Full article at
http://junkfoodscience.blogspot.com/2008/02/how-weve-came-to-believe-that.html


The majority of the participants were Quakers, a science article about this:
http://jn.nutrition.org/cgi/content/abstract/135/6/1347

 

[Tatyana]

An article from the University of Minnesota about the study:
http://www.epi.umn.edu/about/history/lab.shtm#starvation


The effects of semi-starvation
http://www.possibility.com/wiki/index.php?title=EffectsOfSemiStarvation


The Effects Of Starvation On Behavior: Implications for Eating Disorders

by David M. Garner, Ph.D.

The following is an adaptation of a portion of a book chapter: Garner, D.M. (1997). Psychoeducational principles in the treatment of eating disorders. In: Handbook for Treatment of Eating Disorders. (145-177). D.M. Garner & P.E. Garfinkel (Eds). New York, NY: Guilford Press.

One of the most important advancements in the understanding of eating disorders is the recognition that severe and prolonged dietary restriction can lead to serious physical and psychological complications (Garner, 1997). Many of the symptoms once thought to be primary features of anorexia nervosa are actually symptoms of starvation. Given what we know about the biology of weight regulation, what is the impact of weight suppression on the individual? This is particularly relevant for those with anorexia nervosa, but is also important for people with eating disorders who have lost significant amounts of body weight. Perhaps the most powerful illustration of the effects of restrictive dieting and weight loss on behavior is an experimental study conducted almost 50 years ago and published in 1950 by Ancel Keys and his colleagues at the University of Minnesota (Keys et al., 1950). The experiment involved carefully studying 36 young, healthy, psychologically normal men while restricting their caloric intake for 6 months. More than 100 men volunteered for the study as an alternative to military service; the 36 selected had the highest levels of physical and psychological health, as well as the most commitment to the objectives of the experiment. What makes the "starvation study" (as it is commonly known) so important is that many of the experiences observed in the volunteers are the same as those experienced by patients with eating disorders. This section of this chapter is a summary of the changes observed in the Minnesota study.

During the first 3 months of the semistarvation experiment, the volunteers ate normally while their behavior, personality, and eating patterns were studied in detail. During the next 6 months, the men were restricted to approximately half of their former food intake and lost, on average, approximately 25% of their former weight. Although this was described as a study of "semistarvation," it is important to keep in mind that cutting the men's rations to half of their former intake is precisely the level of caloric deficit used to define "conservative" treatments for obesity (Stunkard, 1993). The 6 months of weight loss were followed by 3 months of rehabilitation, during which the men were gradually refed. A subgroup was followed for almost 9 months after the re-feeding began. Most of the results were reported for only 32 men, since 4 men were withdrawn either during or at the end of the semistarvation phase. Although the individual responses to weight loss varied considerably, the men experienced dramatic physical, psychological, and social changes. In most cases, these changes persisted during the rehabilitation or re-nourishment phase.

Attitudes and Behavior Related to Food and Eating

One of the most of the striking changes that occurred in the volunteers was a dramatic increase in food preoccupations. The men found concentration on their usual activities increasingly difficult, because they became plagued by incessant thoughts of food and eating. During the semistarvation phase of the experiement, food became a principal topic of conversation, reading, and daydreams. Rating scales revealed that the men experienced an increase in thinking about food, as well as corresponding declines in interest in sex and activity during semistarvation.


One man was released from the experiment at the end of the semistarvation period because of suspicions that he was unable to adhere to the diet. He experienced serious difficulties when confronted with unlimited access to food "He repeatedly went through the cycle of eating tremendous quantities of food, becoming sick, and then starting all over again" (p. 890). During the refeeding phase of the experiment, many of the men lost control of their appetites and "ate more or less continuously" (p. 843).

Even after 12 weeks of refeeding, the men frequently complained of increased hunger immediately following a large meal.

During the weekends in particular, some of the men found it difficult to stop eating. Their daily intake commonly ranged between 8,000 and 10,000 calories

After about 5 months of refeeding, the majority of the men reported some normalization of their eating patterns, but for some the extreme overconsumption persisted "No. 108 would eat and eat until he could hardly swallow any more and then he felt like eating half an hour later" (p. 847). More than 8 months after renourishment began, most men had returned to normal eating patterns; however, a few were still eating abnormal amounts "No. 9 ate about 25 percent more than his pre-starvation amount; once he started to reduce but got so hungry he could not stand it" (p. 847).

Factors distinguishing men who rapidly normalized their eating from those who continued to eat prodigious amounts were not identified. Nevertheless, the main findings here are as follows: Serious binge eating developed in a subgroup of men, and this tendency persisted in come cases for months after free access to food was reintroduced; however, the majority of men reported gradually returning to eating normal amounts of food after about 5 months of refeeding. Thus, the fact that binge eating was experimentally produced in some of these normal young men should temper speculations about primary psychological disturbances as the cause of binge eating in patients with eating disorders. These findings are supported by a large body of research indicating that habitual dieters display marked overcompensation in eating behavior that is similar to the binge eating observed in eating disorders (Polivy & Herman, 1985, 1987; Wardle & Beinart, 1981). Polivy et al., (1994) compared a group of former World War II prisoners of war and non-interned veterans and found that the former prisoners lost an average of 10.5 Kg. They also reported a significantly higher frequency of binge eating than non-interned veterans according to a self-report questionnaire sent by mail.

Emotional and Personality Changes

The experimental procedures involved selecting volunteers who were the most physically and psychologically robust. "The psychobiological 'stamina' of the subjects was unquestionably superior to that likely to be found in any random or more generally representative sample of the population" (pp. 915-916).

Although the subjects were psychologically healthy prior to the experiment, most experienced significant emotional deterioration as a result of semistarvation. Most of the subjects experienced periods during which their emotional distress was quite severe; almost 20% experienced extreme emotional deterioration that markedly interfered with their functioning. Depression became more severe during the course of the experiment. Elation was observed occasionally, but this was inevitably followed by "low periods." Mood swings were extreme for some of the volunteers


Irritability and frequent outbursts of anger were common, although the men had quite tolerant dispositions prior to starvation. For most subjects, anxiety became more evident. As the experiment progressed, many of the formerly even-tempered men began biting their nails or smoking because they felt nervous. Apathy also became common, and some men who had been quite fastidious neglected various aspects of personal hygiene. During semistarvation, two subjects developed disturbances of "psychotic" proportions. During the refeeding period, emotional disturbance did not vanish immediately but persisted for several weeks, with some men actually becoming more depressed, irritable, argumentative, and negativistic than they had been during semistarvation.

Several days latter, this man actually did chop off three fingers of one hand in response to the stress.

Standardized personality testing with the Minnesota Multiphasic Personality Inventory (MMPI) revealed that semistarvation resulted in significant increases on the Depression, Hysteria, and Hpochondriasis scales. The MMPI profiles for a small minority of subjects confirmed the clinical impression of incredible deterioration as a result of semistarvation. One man who scored well within normal limits at initial testing, but after 10 weeks of semistarvation and a weight loss of only about 4.5 kg (10 pounds, or approximately 7% of his original body weight), gross personality disturbances were evident on the MMPI. Depression and general disorganization were particularly striking consequences of starvation for several of the men who became the most emotionally disturbed.

Social and Sexual Changes

The extraordinary impact of semistarvation was reflected in the social changes experienced by most of the volunteers. Although originally quite gregarious, the men became progressively more withdrawn and isolated. Humor and the sense of comradeship diminished amidst growing feelings of social inadequacy. The volunteers' social contacts with women also declined sharply during semistarvation. Those who continued to see women socially found that the relationships became strained. These changes are illustrated in the account from one man's diary:

I am one of about three or four who still go out with girls. I fell in love with a girl during the control period but I see her only occasionally now. It's almost too much trouble to see her even when she visits me in the lab. It requires effort to hold her hand. Entertainment must be tame. If we see a show, the most interesting part of it is contained in scenes where people are eating. (p. 853)
Sexual interests were likewise drastically reduced. Masturbation, sexual fantasies, and sexual impulses either ceased or became much less common. One subject graphically stated that he had "no more sexual feeling than a sick oyster." (Even this peculiar metaphor made reference to food.) Keys et al. observed that "many of the men welcomed the freedom from sexual tensions and frustrations normally present in young adult men" (p. 840). The fact that starvation perceptibly altered sexual urges and associated conflicts is of particular interest, since it has been hypothesized that this process is the driving force behind the dieting of many anorexia nervosa patients. According to Crisp (1980), anorexia nervosa is a adaptive disorder in the sense that it curtails sexual concerns for which the adolescent feels unprepared. During rehabilitation, sexual interest was slow to return. Even after 3 months, the men judged themselves to be far from normal in this area. However, after 8 months of renourishment, virtually all of the men had recovered their interest in sex.

Cognitive and Physical Changes

The volunteers reported impaired concentration, alertness, comprehension, and judgment during semistarvation; however, formal intellectual testing revealed no signs of diminished intellectual abilities. As the 6 months of semistarvation progressed, the volunteers exhibited many physical changes, including gastrointestinal discomfort; decreased need for sleep; dizziness; headaches; hypersensitivity to noise and light; reduced strength; poor motor control; edema (an excess of fluid causing swelling); hair loss; decreased tolerance for cold temperatures (cold hands and feet); visual disturbances (i.e., inability to focus, eye aches, "spots" in the visual fields); auditory disturbances (i.e., ringing noise in the ears); and paresthesias (i.e., abnormal tingling or prickling sensations, especially in the hands or feet).

Various changes reflected an overall slowing of the body's physiological processes. There were decreases in body temperature, heart rate, and respiration, as well as in basal metabolic rate (BMR). BMR is the amount of energy (in calories) that the body requires at rest (i.e., no physical activity) in order to carry out normal physiological processes. It accounts for about two-thirds of the body's total energy needs, with the remainder being used during physical activity. At the end of semistarvation, the men's BMRs had dropped by about 40% from normal levels. This drop, as well as other physical changes, reflects the body's extraordinary ability to adapt to low caloric intake by reducing its need for energy. More recent recent research has shown that metabolic rate is markedly reduced even among dieters who do not have a history of dramatic weight loss (Platte, Wurmser, Wade, Mecheril & Pirke, 1996). During refeeding, Keys et al. found that metabolism speeded up, with those consuming the greatest number of calories experiencing the largest rise in BMR. The group of volunteers who received a relatively small increment in calories during refeeding (400 calories more than during semistarvation) had no rise in BMR for the first 3 weeks. Consuming larger amounts of food caused a sharp increase in the energy burned through metabolic processes.

Significance of the "Starvation Study"

As is readily apparent from the preceding description of the Minnesota experiment, many of the symptoms that might have been thought to be specific to anorexia nervosa and bulimia nervosa are actually the results of starvation (Pirke & Ploog, 1987). These are not limited to food and weight, but extend to virtually all areas of psychological and social functioning. Since many of the symptoms that have been postulated to cause these disorders may actually result from undernutrition, it is absolutely essential that weight be returned to "normal" levels so that psychological functioning can be accurately assessed.

The profound effects of starvation also illustrate the tremendous adaptive capacity of the human body and the intense biological pressure on the organism to maintain a relatively consistent body weight. This makes complete evolutionary sense. Over hundreds of thousands of years of human evolution, a major threat to the survival of the organism was starvation. If weight had not been carefully modulated and controlled internally, early humans most certainly would simply have died when food was scarce or when their interest was captured by countless other aspects of living. The Keys et al. "starvation study" illustrates how the human being becomes more oriented toward food when starved and how other pursuits important to the survival of the species (e.g., social and sexual functioning) become subordinate to the primary drive toward food.

One of the most notable implications of the Minnesota experiment is that it challenges the popular notion that body weight is easily altered if one simply exercises a bit of "willpower." It also demonstrates that the body is not simply "reprogrammed" at a lower set point once weight loss has been achieved. The volunteers' experimental diet was unsuccessful in overriding their bodies' strong propensity to defend a particular weight level. Again, it is important to emphasize that following the months of refeeding, the Minnesota volunteers did not skyrocket into obesity. On the average, they gained back their original weight plus about 10%; then, over the next 6 months, their weight gradually declined. By the end of the follow-up period, they were approaching their preexperiment weight levels.

Providing patients with eating disorders with the above account of the semistarvation study can be very useful in giving them an "explanation" for many of the emotional, cognitive and behavioral symptoms that they experience. This as well as other educational materials (Garner, 1997) is based on the assumption that eating disorder patients often suffer from misconceptions about the factors that cause and then maintain symptoms. It is further assumed that patients may be less likely to persist in self-defeating symptoms if they are made truly aware of the scientific evidence regarding factors that perpetuate eating disorders. The educational approach conveys the message that the responsibility for change rests with the patient; this is aimed at increasing motivation and reducing defensiveness. The operating assumption is that the patient is a responsible and rational partner in a collaborative relationship.

References

Crisp, A. J. (1980)). Anorexia Nervosa: Let me be. London: Academic Press.

Crisp, A. H., Hsu, L. K. G., & Harding, B. (1980). The starving hoarder and voracious spender: Stealing in anorexia nervosa. Journal of Psychosomatic Research, 24, 225-231.

Garner, D.M. (1997). Psychoeducational principles in the treatment of eating disorders. In: Handbook for Treatment of Eating Disorders. (145-177). D.M. Garner & P.E. Garfinkel (Eds). New York, NY: Guilford Press.

Fantino, M., & Cabanac, M. (1980). Body weight regulation with a proportional hoarding response in the rat. Physiology and Behavior, 24, 939-942.

Keys, A., Brozek, J., Henschel, A., Mickelsen, O., & Taylor, H. L. (1950). The biology of human starvation (2 vols.). Minneapolis: University of Minnesota Press.

Pirke, K. M., & Ploog, D. (1987). Biology of human starvation. In P. J. V. Beumont, G. D. Burrows, & R. C. Casper (Eds.), Handbook of eating disorders: Part 1 Anorexia and bulimia nervosa (pp. 79-102). New York: Elsevier.

Platte, P., Wurmser, H., Wade, S. E., Mecheril, A., & Pirke, K. M. (1996). Resting metabolic rate and diet-induced thermogenesis in restrained and unrestrained eaters. International Journal of Eating Disorders, 20, 33-41.

Polivy, J., Zeitlin, S.B., Herman, C.P. & Beal, A.L. (1994). Food restriction and binge eating: A study of former prisioners of war. Journal of Abnormal Psychology, 103, 409-411.

Polivy, J., & Herman, C.P. (1985). Dieting and bingeing: A causal analysis. American Psychologist, 40, 193-201.

Polivy, J., & Herman, C. P. (1987). Diagnosis and treatment of normal eating. Journal of Consulting and Clinical Psychology, 55, 635-644.

Stunkard, A. J. (1993). Introduction and overview. In A. J. Stunkard & T. A. Wadden (Eds.), Obesity: Theory and therapy (2nd Ed., pp. 1-10). New York: Raven Press.

Wardle, J., & Beinart, H. (1981). Binge eating: A theoretical review. British Journal of Clinical Psychology, 19-20, 97-109.

Retrieved from "http://www.possibility.com/wiki/index.php?title=EffectsOfSemiStarvation"

 

[Bikini Mod]

EXCELLENT READ! Thanks Tatyana

If only more people would *get* this.

 

[the_alcatraz]

very good read. I actually read all of this

 

[sessa]

Wow, I have totally been there before. Hard dieting is not the answer....
I totally lost interest in everything and i also lost a lot of muscle and yup my BMR went down and the last month of my dieting phase I didn't change too much. I seemed to loose muscle and fat at the same rate. That article is SO true!

I am now working with a new trainer to get me ready this year, and we are dieting me on higher cals, and so far so good I am sure I will plateau at some point and we will adjust it then, but I was surprised at the 2 different dieting philosophy's of the 2 trainers I have worked with.

 

[Tatyana]

I thought I would bump this as this is one of the few scientific studies we have that have measured the effects of semi-starvation diet, both physically and psychologically.

I would also argue that a BBing comp diet, and some of the rigorous diets that women seem to love to put themselves through are also semi-starvation diets.

The body protects us against starvation.

It really doesn't work all that well in the long run, in fact it appears that it does more damage in the long run.

With fat loss, while it really, really sucks, it is slow and steady is the way to go.

 

[Gatorlee04]

Wow... great stuff. Thanks for posting it!