ANOREXIA, BULIMIA and THE MINNESOTA STARVATION EXPERIMENT
Starvation experiment participant Sam Legg
There are striking parallels between victims of semi-starvation/starvation and those who suffer from bulimia and/or anorexia nervosa.
There are striking parallels between victims of semi-starvation/starvation and those who suffer from bulimia and/or anorexia nervosa.
Physiologist Ancel Keys led the starvation experiment
Probably
the most systematic study of the effects of starvation was conducted
over 30years ago by Ancel Keys and his colleagues at the University of
Minnesota (Keys, Brozek, Henschel, Mickelsen & Taylor, 1950). The
experiment, commonly referred to as the Minnesota Starvation Experiment/Study,
involved restricting the caloric intake of 36 young, healthy,
psychologically normal men who had volunteered for the study as an
alternative to military service.
During the first three months of
the experiment, the men ate normally, while their behavior,
personality, and eating patterns were studied in detail. During the
subsequent six months, the men were restricted to approximately half of
their former food intake and lost, on average, 25% of their original
body weight. This was followed by three months of rehabilitation, during
which time the men were gradually re-fed.
Although their
individual responses varied considerably, the men experienced dramatic
physical, psychological, and social changes as a result of the
starvation. In most cases, these changes persisted during the
rehabilitation or re-nourishment phase.
An inevitable result of
starvation was a dramatic increase in preoccupation with food. The men
found concentration on their usual activities increasingly difficult,
since they were plagued by persistent thoughts of food and eating. In
fact, food became a principal topic of conversation, reading, and
daydreams. Many of the men began reading cookbooks and collecting
recipes.
Starvation subjects became overwelmingly preocupied with food.
Some collected dozens of cookbooks
Some
developed a sudden interest in collecting coffee-pots, hot plates, and
other kitchen utensils. This hoarding even extended to non-food-related
items:
Some of the men collected old books, unnecessary
second-hand clothes, knick knacks, and other "junk." Often after making
such purchases, which could be afforded only with sacrifice, the men
would be puzzled as to why they had bought such, more or less, useless
articles. (Keys et al., 1950, p. 837)
One man even began
rummaging through garbage cans with the hope of finding something that
he might need. This general tendency to hoard has been observed in
starved anorexic patients (Crisp, Hsu, & Harding, 1980) and even in rats deprived of food (Fantino & Cabanac, 1980).
Despite
little interest in culinary matters prior to the experiment, almost 40%
of the men mentioned cooking as part of their post-experiment plans.
For some, the fascination was so great that they actually changed
occupations after the experiment: three became chefs, and one went into
agriculture.
During starvation, the volunteers' eating habits
underwent remarkable changes. The men spent much of the day planning how
they would eat their allotment of food. Much of their behavior served
the purpose of prolonging the ingestion and hedonic appeal or saliency
of food. The men often ate in silence and devoted total attention to
consumption.
The
Minnesota subjects were often caught between conflicting desires to
gulp their food down ravenously and consume it slowly so that the taste
and odour of each morsel would be fully appreciated. Toward the end of
starvation, some of the men would dawdle for almost two hours over a
meal which previously they would have consumed in a matter of minutes.
(Keys et al.,1950, p. 833)
The men demanded that their food be
served hot, and they made unusual concoctions by mixing foods together.
There was a tremendous increase in the use of salt and spices. The
consumption of coffee and tea increased so dramatically that the men had
to be limited to 9 cups per day; similarly, gum chewing became
excessive and had to be limited after it was discovered that one man was
chewing as many as 40 packages a day.
During the 12-week
rehabilitation phase, most of these attitudes and behaviors persisted.
For a small number of men, these became even more marked during the
first six weeks of refeeding:
In many cases the men were not
content to eat "normal" menus but persevered in their habits of making
fantastic concoctions and combinations. The free choice of ingredients,
moreover, stimulated "creative" and "experimental" playing with food,
licking of plates, and neglect of table manners persisted. (Keys et al.,
1950, p. 843)
Bulimia
During the
starvation regimen, all of the volunteers reported increased hunger;
some appeared able to tolerate the experience fairly well, but for
others it created intense concern, or even became intolerable. Several
men failed to adhere to their diets and reported episodes of bulimia followed
by self-reproach. While working in a grocery store, one subject
suffered a complete loss of willpower and ate several cookies, a sack of
popcorn, and two overripe bananas before he could "regain control" of
himself. He immediately suffered a severe emotional upset, with nausea,
and upon returning to the laboratory he vomited. He was
self-deprecatory, expressing disgust and self-criticism. (Keys et al.,
1950,p. 887)
During the eighth week of starvation, another subject "flagrantly
broke the dietary rules, eating several sundaes and malted milks; he
even stole some penny candies. He promptly confessed the whole episode,
[and] became self-deprecatory" (Keys et al.,1950, p. 884).
When
presented with greater amounts of food during rehabilitation, many of
the men lost control of their appetites and "ate more or less
continuously" (Keys et al., 1950, p. 843). Even after 12 weeks of
rehabilitation, the men frequently complained that they experienced an
increase in hunger immediately following a large meal:
[One
of the volunteers] ate immense meals (a daily estimate of 5,000 to
6,000 calories) and yet started snacking" an hour after he finished a
meal. [Another] ate as much as he could hold during the three regular
meals and ate snacks in the morning, afternoon and evening. (Keys et al., 1950, p. 846)
This
gluttony resulted in a high incidence of headaches, gastrointestinal
distress and unusual sleepiness. Several men had spells of nausea and
vomiting. One man required aspiration and hospitalization for several
days. (Keys et at., 1950, p. 843)
There
were weekend "splurges" in which intake commonly ranged between 8,000
and 10,000 calories. The men frequently found it difficult to stop
eating:
"Subject
No. 20 stuffs himself until he is bursting at the seams, to the point
of being nearly sick and still feels hungry; No. 120 reported that he
had to discipline himself to keep from eating so much as to become ill;
No. 1 ate until he was uncomfortably full; and subject no. 30 had so
little control over the mechanics of "piling it in" that he simply had
to stay away from food because he could not find a point of satiation
even when he was "full to the gills." . . . Subject no. 26 would just as
soon have eaten six meals instead of three." (Keys et al., 1950, p. 847)
After
about five months of rehabilitation, the majority of the men reported
some normalization of their eating patterns; however, 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" (Keys et al., 1950, p. 847).
More than 8 months after renourishment, a few men were still eating abnormal amounts, and one man still reported consuming "about 25 per cent more than his pre-starvation amount; once he started to reduce but got so hungry he could not stand it" (Keys et al., 1950, p. 847).
Factors
that distinguished men who rapidly normalized their eating from those
who continued to eat prodigious amounts were not identified. However,
the important point here is that there were tremendous differences among
volunteers in their responses to the starvation experience, and that a
subset of these men developed bulimia, which persisted many months after they were permitted free access to food.
Emotional Changes
The
strict procedures used to select subjects for the experiment led the
experimenters to conclude that 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" (Keys
et al., 1950, p. 916). Although the subjects were psychologically
healthy prior to the experiment, most experienced significant emotional
changes as a result of semi-starvation. Some reported transitory and
others protracted periods of depression, with an overall lowering of the
threshold for depression. Occasionally elation was observed, but this
was inevitably followed by "low periods." Although the men had quite
tolerant dispositions prior to starvation, tolerance was replaced by
irritability and frequent outbursts of anger. 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 became common, and some men who had been quite
fastidious neglected various aspects of personal hygiene. Most of the
subjects experienced periods during which their emotional distress was
quite severe, and all exhibited the symptoms of "semi-starvation
neurosis" described above.
Almost 20% of the group experienced
extreme emotional deterioration that markedly interfered with their
functioning. Standardized personality testing with the Minnesota Multiphasic Personality Inventory (MMPI)
revealed that semi-starvation resulted in significant increases in
depression, hysteria, and hypochondriasis for the group. This profile
has been referred to as the "neurotic triad" and is observed among
different groups of neurotically disturbed individuals (Greene, 1980).
These emotional aberrations did not vanish immediately during
rehabilitation, but persisted for several weeks, with some men actually
becoming more depressed, irritable, argumentative, and negativistic than
they had been during semi-starvation.
During semi-starvation two
subjects developed disturbances of "psychotic" proportions. One of
these was unable to adhere to the diet and developed alarming symptoms:
"[He
exhibited] a compulsive attraction to [garbage] and a strong, almost
compelling, desire to root in garbage cans [for food to eat]. He
repeatedly went through the cycle of eating tremendous quantities of
food, becoming sick, and then starting all over again [and) became
emotionally disturbed enough to seek admission voluntarily to the
psychiatric ward of the University Hospitals." (Keys et al., 1950, p. 890)
After nine weeks of starvation, another subject exhibited signs of disturbance:
"[He
went on a] spree of shoplifting, stealing trinkets that had little or
no intrinsic value. He developed a violent emotional outburst with
flight of ideas, weeping, talk of suicide and threats of violence.
Because of the alarming nature of his symptoms, he was released from the
experiment and admitted to the psychiatric ward of the University
Hospitals." (Keys et al., 1950, p. 885)
Another man chopped off three fingers of one hand in response to stress.
For a few volunteers, mood swings were extreme:
"[One
subject] experienced a number of periods in which his spirits were
definitely high. These elated periods alternated with times in which he
suffered "a deep dark depression." [He] felt that he had reached the end
of his rope [and] expressed the fear that he was going crazy [and]
losing his inhibitions." (Keys et al., 1950, p. 903)
Personality
testing (with the MMPI) of a small minority of subjects confirmed the
clinical impression of incredible deterioration as a result of
semi-starvation. "...one
man's personality profile [was] initially...well within normal limits,
but after 10 weeks of semi-starvation and a weight loss of only about
4.5 kg (10 lb, or approximately 7% of his original body weight), gross
personality disturbances were evident." On the second
testing, all of the MMPI scales were elevated, with severe personality
disturbance on the scales for neurosis as well as those for psychosis.
Depression and general disorganization were particularly striking
consequences of starvation for several of the men who became the most
emotionally disturbed.
It may be concluded from clinical
observation as well as standardized personality testing that the
individual emotional response to semi-starvation conditions varies
considerably. Some of the volunteers in Keys et al.'s experiment seemed
to cope relatively well, and others displayed extraordinary disturbance
following weight loss. The type of disturbance was quite similar to that
described in obese individuals exposed to "therapeutic" semi-starvation
(Glucksmaii & Hirsch, 1969; Rowland, 1970).
In the Minnesota
experiment, pre-starvation personality adjustment did not predict the
emotional response to caloric restriction. Some of the men who appeared
to be the most stable reacted with severe disturbance. The fact that
people respond so differently and unpredictably to weight loss is
clearly relevant to an assessment of those who have dieted below their
optimal weight.
Since the emotional difficulties in the Minnesota
volunteers did not immediately reverse themselves during
rehabilitation, it may be assumed that the abnormalities were related
more to body weight than to short-term caloric intake. It may be
concluded that many of the psychological disturbances found in anorexia nervosa and bulimia may be the result of the semistarvation process.
Social and Sexual Changes
The
extraordinary impact of semi-starvation is reflected in the social
changes experienced by most of the volunteers. Although originally quite
gregarious, the men became progressively more withdrawn and isolated.
Humour and the sense of comradeship diminished markedly amidst growing
feelings of social inadequacy:
Social initiative especially, and
sociability in general, underwent a remarkable change. The men became
reluctant to plan activities, to make decisions, and to participate in
group activities. They spent more and more time alone. It became "too
much trouble" or "too tiring" to have contact with other people. (Keys
et al., 1950, pp. 836-837)
The volunteers' social contacts with
women also declined sharply during semi-starvation. Those who continued
to see women socially found that the relationships became strained.
These changes are illustrated in the description 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." (Keys et al., 1950, 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.) The investigators observed that "many of the men welcomed the freedom from sexual tensions and frustrations normally present in young adult men" (Keys et al., 1950, 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 an 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 three
months, the men judged themselves to be far from normal in this area.
However, after eight months of re-nourishment, virtually all of the men
had recovered their interest in sex.
Cognitive Changes
The
volunteers reported impaired concentration, alertness, comprehension,
and judgment during semi-starvation; however, formal intellectual
testing revealed no signs of diminished intellectual abilities.
Physical Changes
As
the six months of semi-starvation progressed, the volunteers exhibited
many physical changes, including the following: 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
paresthesia (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 (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 semi-starvation, the men's BMRs had dropped by
about 40% from normal. 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. One volunteer described that it was as
if his "body flame [were] burning as low as possible to conserve precious fuel and still maintain life process" (Keys et al., 1950, p. 852).
During
rehabilitation, metabolism again 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 rehabilitation (400 calories more than during
semi-starvation) had no rise in BMR for the first three weeks. Consuming
larger amounts of food caused a sharp increase in the energy burned
through metabolic processes.
The changes in body fat and muscle
in relation to overall body weight during semi-starvation and
rehabilitation are of considerable interest. While weight declined about 25%, the percentage of body fat fell almost 70%, and muscle decreased about 40%. Upon
re-feeding, a greater proportion of the "new weight" was fat; in the
eighth month of rehabilitation, the volunteers were at about 100% of
their original body weight, but had approximately 140% of their original body fat! How did the men feel about their weight gain during rehabilitation?
Those
subjects who gained the most weight became concerned about their
increased sluggishness, general flabbiness, and the tendency of fat to
accumulate in the abdomen and buttocks. (Keys et al., 1950, p. 828)
A page of Harold Blickenstaff's diary during his participation in the starvation experiment.
Here, Blickenstaff tracks his weight loss
These complaints are similar to those of many bulimic and anorexic
patients as they gain weight. Besides their typical fear of weight
gain, they often report "feeling fat" and are worried about acquiring
distended stomachs. However, the body weight and relative body fat of
the Minnesota volunteers had begun to approach the pre-experiment levels
after just over a year.
Physical Activity
In
general, the men responded to semi-starvation with reduced physical
activity. They became tired, weak, listless, and apathetic, and
complained of lack of energy. Voluntary movements became noticeably
slower. However, according to the original report,
"...some
men exercised deliberately at times. Some of them attempted to lose
weight by driving themselves through periods of excessive expenditure of
energy in order either to obtain increased bread rations or to avoid
reduction in rations." (Keys et al., 1950, p. 828)
Starvation experiment participants on the treadmill
This is similar to the practice of some anorexic and bulimic
patients, who feel that if they exercise strenuously, they can allow
themselves a bit more to eat. The difference is that for the patients
the caloric limitations are self-imposed.
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 or bulimia
are actually the result of starvation. 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
under-nutrition, it is absolutely essential that weight be returned to
"normal" levels in order that emotional disturbances may 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 the 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, animals most certainly would simply have died
when food was scarce, or when their interest was captured by countless
other aspects of living. The 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 starvation experiment is that
it provides compelling evidence against the popular notion that body
weight is easily altered if one simply exercises a bit of "will power." It also demonstrates that the body is not simply "reprogrammed" to adjust to a lower weight once it has been achieved. The volunteers' experimental diet was unsuccessful in
overriding their bodies' strong propensity to defend a particular
weight level. One might argue that this is fine as long as a person is
not obese to start with; as we point out later, however, these same
principles seem to apply just as much to those who are naturally heavy
as to those who have always been lean.
It should be emphasized
that following the months of rehabilitation, 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 pre-experiment weight levels.
American RadioWorks has an excellent article on the Minnesota Starvation Experiment here:
A
half-hour later, Jeremy approached the counter again and dug his hand
into his pocket, plucking out a tiny, folded-up coupon. It entitled him
to a kids' meal—a third the size of an adult sub. Jeremy got a scoop of
tuna fish on wheat, a small milk, a four-ounce yogurt, and a cookie.
Other celebrities rumored to have suffered from "manorexia" include Ethan Hawke and Billy Bob Thornton (post-Angelina Jolie).
"It
serves two purposes," Jeremy says. "It serves a very applied purpose in
that if you're doing the behaviors, you don't have time to think about
being gay. And also being malnourished, you don't feel sexual, so you
don't have to worry about being gay or straight."
