An Evolutionary Approach to Understanding and Treating Anorexia Nervosa and Other Eating Problems

By Shan Guisinger

Understanding and Treating Anorexia Nervosa: A Biopsychosocial Approach offers a new evidence-based intervention for anorexia nervosa that accounts for strange symptoms. The book provides an intervention that is more accurately tailored to the three phases (biological, psychological and social) of interventions observed in this disorder. The book's chapters walk the reader through motivational interviewing, dialectical behavioral therapy, and other clinical techniques to help tailor therapeutic work to specific challenges. Written by Dr. Shan Guisinger, a leading expert in the field, this book will be the main treatment guide for treating anorexia nervosa.

Treating anorexia nervosa (AN) can be one of the hardest job clinicians face. People with AN fear eating despite being seriously underweight and experiencing hallucinations. Current interventions lack options to address such non-traditional symptoms ultimately resulting in relapse.

• Reviews the neuroendocrine changes altering behaviors and attitudes toward eating, activity and body image
• Introduces a novel treatment that relies on the biological, psychological and social phases
• Discusses psychotherapy outcome research on both adolescents and adults

• Language: English
• Publisher: Academic Press
• Release date: Jan 30, 2024
• ISBN: 9780443189050

Shan Guisinger

Shan Guisinger is an eating disorders therapist and researcher. Shan trained as an evolutionary biologist before getting a Ph.D. from the University of California, Berkeley in clinical psychology and doing postdoctoral work at the Yale University’s Eating Disorders Clinic. In her research and practice, she seeks to understand how biological, psychological, and social factors interact to create or ameliorate emotional and eating problems. She has written about how chaos theory can help us understand the spontaneous patterning of evolution and our emotional and cognitive lives. Shan has authored theoretical articles on the interplay of individuality and interpersonal relatedness for The American Psychologist and on the evolutionary sense of anorexia nervosa for Psychological Review. She is coeditor and author of a recent book on some applications of chaos theory to psychology from Oxford University Press.

Book preview

Chapter 1: A brief overview of human evolution and eating problems

Abstract

Our evolution over the last 5 million years has left many of us with genetic vulnerabilities to develop eating disorders and to store fat. Attempting to understand our eating problems without considering the behavioral ecologies of our ancestors has generated incorrect attributions to individual psychopathology, deficits in self-control, and/or biological dysfunctions. Eating disorder symptoms and storing fat evolved as adaptions to survive famine and are composed of behaviors mediated by complex biological mechanisms rather than choice. When our ancestors left subtropical forests they needed new strategies to thrive, including taking extra care to avoid eating dangerous foods, the ability to binge eat when they found a rich, ephemeral food source, and storing fat. When local resources were depleted and mountains, deserts, or other barriers barred further movement, starving individuals able to develop anorexia and hyperactivity searched for new lands.

Keywords

Anorexia nervosa; ARFID; Avoidant restrictive feeding intake disorder; Behavioral ecology; Binge-eating disorder; Bulimia nervosa; Eating disorders symptoms; Evolution; Famine; Fat; Migration; Picky eating; Savannah

Seven million years ago, a period of cooling reduced the area of subtropical forests in Africa where our chimp-like ancestors had a safe, reliable, and familiar diet of ripe fruit, nutritious leaves, and the occasional freshly killed monkey. As climate cooled, the lineage that ultimately led to modern humans began to spend more time searching for food on the savannah (11).

They dug tubers and scavenged other animals' kills; the meat could be rotten, and many plant parts were toxic. Avoidant restrictive feeding intake disorder (ARFID) is the latest eating disorder added to psychiatry's Diagnostic and Statistical Manual of Mental Disorders (DSM), but it may have been the first eating disorder caused by adaptations to our ancestors' new foraging ecology. This foraging environment would have led to the selection for heightened sensory mechanisms to detect signs of poisonous plant parts and spoiled animal remains, to feel repulsion and disgust to these signs, to resist eating them or letting rotten food contaminate other foods. Such evolutionary adaptations may underlie picky eating, now called ARFID. All people pick up cues of rotten meat (putrid smell, slimy texture, off colors) and plant toxins (bitter taste) but the genetic reassortment at sexual reproduction likely deals some unlucky individuals with many mechanisms tuned to be alerted to cues of potentially dangerous foods. It is as though on a sensitivity scale of from 1 to 10 for, people with ARFID are set to 11. There are strategies on how to deal with ARFID and each of the other eating problems in Chapter 10.

As hominids left the subtropical forests of their ancestors and moved into more seasonal or arid regions, they needed new strategies to thrive. People with binge-eating disorder (BID) experience a loss of control over their eating. Intriguingly, most are not fat. Why would such a mechanism have evolved? Before refrigerators and grocery stores, being able to binge eat could allow individuals to utilize foods that would otherwise go to waste. Behavioral and neuroendocrine strategies to gorge on bonanza, windfall, and seasonal food sources probably helped some ancestors thrive as they moved into habitats with seasonal or erratic food availability.

It is hard on the body to eat considerable food at once, and it is normally aversive for the well-fed to gorge but as humans colonized the world, many lineages seem to have developed improved abilities to tolerate binge eating physiologically and an impulse to gorge on a rich or ephemeral food sources at times. Binge eating is not a sign of psychopathology. It is exacerbated by weight loss dieting, but some binges may occur almost randomly when the nonconscious brain's energy regulation center deems the time is right. Offer compassion to yourself if this occurs. We did not evolve with hyperpalatable food and our hunter-gatherer ancestors had more social support and thus perhaps less stress than many of us today.

People with bulimia nervosa (BN) undo an eating binge by vomiting, fasting, or overexercising. Although it seems like a way to have your cake and eat it to, what began as a choice rapidly becomes an addiction. Moreover, BN drives up a person's weight set point over time. Treatment of BN is the one traditional ED success story. Cognitive behavioral therapy (CBT) for BN provides accurate biological information about how food restriction leads to predictable physiological and psychological changes that drive binge eating and purging. When people vomit or undereat, this causes satiety signals to decrease and hunger signals to increase pushing the person into an eating binge, then feeling remorse, and uncomfortably stuffed, many find relief by vomiting, fasting, or overexercising. This process is highly addictive, both the extreme joy of eating when starved and the extreme joy from the relief of anxiety when purging are powerfully rewarded in the same area of the brain that street drugs exploit. People with BN blame themselves and think that they lack willpower (12). In fact, when the brain determines that a person should eat, it turns down their ability to use self-control. The solution is to teach the body that it does not live with famine by not undoing the eating binge. BN patients learn strategies to delay, distract, and seek support for their intentions from others. A powerful incentive for recovery is learning that BN leads to greater weight gain over time. This is because the body is biased to signs of food scarcity, and it reads each purge as a sign of famine and the need to increase the body's fat reserves. Accurate biological and psychological knowledge helps people understand what they must do to recover.

Anorexia nervosa was likely the last adaptation to famine to evolve. People with AN feel it is vitally important to restrict feeding although they are seriously under their healthy weight; they hallucinate fat on their thin bodies, most feel driven to move, and 90% are female (13,14). AN is our deadliest psychiatric illness, causing 600% more cases of death than in the normal population; 20% take their own lives (15). Current treatments are ineffective.

Here I present evidence that AN is initiated by serious weight loss in those with a genetic vulnerability (16). I have long argued that the singular symptoms of AN helped a starving hunter-gatherer to use their last reserves to search for better lands (17). When local resources were depleted and mountains, deserts, or other barriers barred further movement, genetic evidence indicates that energetic, young women able to ignore hunger and fatigue traveled in search for new lands (18).

Storing extra fat is a rare adaptation available only to animals like bears that are not prey. When our ancestors began to use fire and group defense to protect themselves against predators (19), they were freed to store fat. No other primate developed the amazing biological trick of storing much fat and none has colonized every part of the globe. Homo sapiens likely evolved mechanisms to store fat to survive unreliable food availability as they moved into marginal parts of the world. Both natural and sexual selection may have played a part in developing the ability to store fat. Ancient Venus figurines found in Central European caves from 20,000 to 30,000 years ago suggest that fat was prized in a wife.

Being fat is not a sign of an eating disorder. However, the American Medical Association (AMA) recently voted, against the advice of their own committee, to label everyone with a body mass index (BMI) over 30 as having the disease of obesity (BMI is calculated as weight in kilograms divided by height in meters squared (kg/m²)). This is scientifically unsupported, morally harmful, and defies common sense. Humans have always been recognized as coming in three weight morphs (types), constitutionally thin, normal (it would be more appropriate to say average) weight, and constitutionally fat. Although certain metabolic diseases are associated with higher weight, thin people can suffer from them and fat people can have none. Lineages that evolved to store considerable fat likely evolved physiological adaptations to maintain metabolic health at higher weight. Multiple studies have found that cardiorespiratory fitness is more important to health than weight (20). Perhaps some physician voters had internalized Americans' hatred of fat or were motivated by the hope of being paid for treating the disease of being over 30 BMI.

Today, discrimination against fat people is on par with discrimination against racial minorities and it is growing (21). Some obesity experts have said that weight stigmatization is justified to motivate individuals to adopt healthier behaviors (22). People with higher weight are exhorted to diet, but dieting leads to higher weight (2). The weight of the average Americans has increased by 30 pounds over the last 50 years, in part because of epigenetic upregulation of obesity-promoting genes that evolved as adaptations to famine. Evidence that weight loss dieting leads to higher weight is so strong that a review commissioned by the Centers for Medicare Services concluded that CMS should not pay for weight loss programs because they are counterproductive (2).

Comfort and meaning

I hope that evolutionary explanations for ARFID, BED, BN, and AN, and fatness can provide comfort and meaning to sufferers and their therapists and correct over a century of false beliefs about AN. I am not arguing that eating disorders and higher weight do not lead to serious mental and physical illness at times. I am asserting that the fault is in ancient genetic adaptations to famine rather than people's character.

Now we turn back to anorexia nervosa, the most deadly and mysterious eating disorder.

Chapter 2: Understanding anorexia nervosa

Abstract

AN takes over the victim’s mind and compels them to restrict feeding and move actively. In 1980 the DSM III described AN as refusal to maintain normal weight due to relentless pursuit of thinness. Attributing AN to psychological motives has not led to effective treatments. Psychiatrists no longer classify psychiatric illnesses as either organic or functional caused by mental activity except for AN where the intuition persists that it is caused by patients' fear of getting fat, rather than arising from hormonal changes and altered neurocircuits. In 2003, I proposed that serious weight loss triggered biological adaptations selected when migration was the best solution to local famine considerable evidence supported this hypothesis, and I predicted that scientists would find biological mechanism behind the distinctive symptoms. I pointed out that other animals that made a living as omnivorous, opportunistic, nomadic foragers also develop anorexia and hyperactivity when starved.

Keywords

AN experts; Anorexia nervosa; Cognitive behavioral therapy; Current theory-based explanations; Family-based treatment; Fat

There was nothing else in my life, the anorexia controlled every second of every day, every uttered word from my mouth, every fleeting thought in my head. I was no longer myself, and anyone who has had anorexia or known someone with it will have seen that transformation themselves.

Good Girls, Hadley Freeman, 2023.

I felt I had to do something I didn't want to do for a higher purpose. That took over my life.

AN patient quoted by Hilde Bruch in The Golden Cage, 1978.

(23)

Claire

The first client I saw with AN changed the course of my life. I had just received my Ph.D. in clinical psychology from the University of California, Berkeley and begun a private practice. When Claire (I am using a pseudonym and changing some details to protect her privacy) walked into my office I thought she looked like a model. She was tall and very thin, with the big, curly, highlighted hair popular in the 1980s. Warm and open, Claire told me her anorexia had begun at 13 when she joined her mother in giving up sweets for Lent. Before puberty, she had grown 5 in. and was already very thin. She was not trying to lose weight, but when she lost a little it sent her down the rabbit hole described in the epigrams; AN blighted her life for the next 10 years. Claire did not fit the description in the Diagnostic and Statistical Manual of Mental Disorders-III (DSM-III) (24) that sufferers refuse to eat enough. She insisted, I want to eat more, but I can't.

In other ways, Claire was a typical AN patient. She saw fat on her thin body; she felt inexplicably afraid of eating normal amounts or rich foods, and she exercised compulsively.¹ A hairdresser, she was popular for her meticulous work. Claire was a delightful client, engaging, curious, and committed to recovery. Without health insurance, she saved her earnings to pay my fee as we tried on the current theory-based explanations for AN. In the 1980s, AN was attributed to a controlling mother, perfectionism, needs for control, or fear of getting fat. Claire insisted that she felt well accepted and loved by parents who were not controlling. She also denied that she had a fear of getting fat, reminding me that she was trying to gain weight. She did admit to being a perfectionist but exploring her needs for perfection and control did not alter the fear that took over when she tried to eat more. Something was not being reached as we searched together for plausible explanations for her difficulty eating.

When she caught a bad cold and lost more weight, she even became afraid of drinking water. That made no sense. Her fear of ingesting food or water seemed visceral, biological; but I could not imagine why her body would signal that eating was dangerous. I was not able to help her and eventually she stopped coming. Claire haunted me for years.

Diagnostic and Statistical Manual of Mental Disorders-III (DSM-III) in 1980

AN was first described in the Diagnostic and Statistical Manual of Mental Disorders-III (DSM-III) in 1980 (24). Although many AN patients insisted that inadvertent weight loss rather than dieting had led to the disorder the authors of the DSM continued to attribute it to patient's refusal or in later editions, restriction of food. After 1970, when dieting had become common among girls and women striving to attain the new ultra-thin beauty ideal, AN patients began saying that they feared getting fat. Although for 20 centuries, people had given other explanations—the first century AD Greco-Roman physician, Aulus Cornelius Celsus simply wrote: Through great fear someone takes too little food—the DSM authors concluded that fear of getting fat was a primary feature of the disorder (25,26).

Some AN patients insisted that they did not want to look like a fashion model; others reminded the DSM authors that they were not deliberately restricting and had sought treatment to be able to eat normally. Even the anorexic saint, Catherine of Siena insisted to her confessor, I pray to God to allow me to eat like other people, if it was His will (27). Nonetheless, each new edition of the DSM from 1980 to the most recent, The DSM-5-TR in 2022, continued to attribute AN to the patients' fears of getting fat and psychologically motivated restriction of feeding.

Cognitive behavioral therapy for AN was developed to use CBT strategies to convince patients that they overvalued their body size for their self-esteem (28). Therapists also treated their patients' anxiety, perfectionism, needs for control, or trauma from bullying or sexual assault in the hope that this would help them to eat normally. Family systems therapists focused on overly controlling mothers. In the last century, parents were commonly separated from their children for treatment, a trauma to mother and child that sometimes ended in the child's death. The 21st century saw family systems researchers bringing parents into the team. However, they continued to believe that poor parental boundaries were causal and they attempted to strengthen the parents' confidence that they could get their children to eat without appreciating how difficult this was for the child.

AN experts' confident theorizing about psychological motives and defects has not led to effective treatments (29). A randomized controlled clinical trial of two popular therapies, cognitive behavioral therapy for AN (CBT-E), which is based on the belief that anorexia is due to fear of getting fat and interpersonal therapy (IP), which looks for dysfunction in patients' relationships found both performed worse than a control group (30). The control group offered no theory to explain the illness but gave emotional and nutritional support, considered the minimum one could offer in a control group for a deadly disorder (30). This study's outcome indicated that it does not help people recover if their therapist believes that their fear of getting fat or their loved ones made them ill.

Certainly, many patients have recovered with the help of caring and curious therapists of every stripe. However, the McIntosh study may reflect a broader reality. Epidemiological evidence suggests that conventional therapies may be iatrogenic, that is, they may make the disorder worse. Large population studies found that AN is far more common in young women than had been thought based on clinical statistics. They found evidence that up to 3.7% of young European women develop the disorder and most recover on their own without ever being diagnosed or treated. This contrasts with traditional therapies where less than half fully recover (29).

Best practice today

It was considered a radical break with the past when family-based treatment (FBT) included parents on the treatment team and sought to empower them to refeed their child, (31). Focusing on weight restoration improved outcomes, but even then treatment is often ineffective (32). Consider this 2021 description by Karl Deisseroth, a psychiatrist and neuroscientist of families and adolescents receiving FBT at Stanford University Hospital.

On the pediatric ward, I had seen AN in its most severe and devastating form—a disease dwelling mostly within teenage girls, with both patients and families consumed. These were uniquely deadly dynamics I saw, mixing love and anger, with parents frantic to feed their young, full of fury at this inexplicable monster. Families would blame each other, with hints and digs and clawed swipes and violent detonations, since there was nobody else in reach, and no other way to make sense of their emaciated child, surrounded by yet refusing food. There is no clearer example in psychiatry of human suffering that would be addressed just by understanding—even without a cure. These were children who had been so strong—stars and performers, disciplined across dimensions, utterly beloved.

Karl Deisseroth, Projections, 2021 p. 163; italics mine.

Diesseroth captures the agonizing reality in which these anorexia patients and their families find themselves and their inevitable blaming of each other with hints and digs and clawed swipes. Parents' appreciated being included in the treatment, but some complained that their therapist offered little practical help on how to help their child with her extreme, delusional fear or an explanation for why she was afraid. (31). For Diesseroth, the parents, and the treatment team the juxtaposition of youthful promise and family devotion with a mysterious life-sucking pathology remains a tragic mystery.

Historical understanding of AN

Saints or hysterics?

There was a small epidemic of AN during the early Middle Ages (33). The Catholic Church prescribed so many fasts that some pious individuals, mostly female, developed holy anorexia. They were believed to have been chosen by God to live without carnal needs for an important mission. For example, St. Gregory of Nyssa wrote,

What human words can make you realize such a life as this, a life on the borderline between human and celestial nature? That nature should be free of human weakness is more than can be expected from mankind, but these women fell short of the angelic and unmaterial only in so far as they appeared in bodily form, were contained in a human frame, and were dependent on the organs of sense.

In Holy Anorexia, Rudolf Bell describes how these religious women pushed themselves through hunger and fatigue to care for the sick and the poor (27). The Church canonized over 80 people with holy anorexia as saints. A patron saint of Italy, Catherine of Siena died of malnutrition at 32, but not before she successfully challenged Pope Gregory XI to return the seat of the papacy from Avignon to Rome. The Pope was so impressed by her that he sent her as his emissary to negotiate peace with Florence.

Joan of Arc lived in the 15th century during the 100 Years War. Joan often fasted and observers commented on how little she ate (34). She did not menstruate and showed extraordinary physical endurance and athleticism. When English soldiers pillaged her village, burned the church, raped girls and women, (Joan and her family had fled) and the French army did nothing she heard God call her to act (35). Perhaps emboldened by her exceptional physical and mental toughness, she understood herself part of God's plan to drive the English out of France. Joan's otherworldly confidence rallied France's demoralized troops to lift the siege of Orleans. She was only 17 when her determined leadership drove the English out of the Loire valley. Her actions ultimately ended the Hundred Years War, although by then she had been burned alive at the stake.

Scientific explanations

Scientific men of the Enlightenment thought claims that fasting saints existed on nothing but God's grace wwere just the sort of superstitious, unscientific explanations they were battling (36). They were less intrigued by their patients' abilities to resist hunger and work actively when starving than by their delusional and aggravating fear of eating, drive to move, and conviction that they had fat stores. Walter Vandereycken and Ron Van Deth wrote that the disorder became part of a philosophical battle between materialists and spiritualists (25). In 1878 Dr. Campbell wrote in the British Medical Journal, No one should be considered sane who, without cause, starves so as to endanger health and life. Should cases of ‘fasting girls’ continue to crop up, I think it would be well if the subject were brought under the notice of the Commissioners in Lunacy. The fact that most patients were teen girls or women led doctors to interpret the disorder according to Victorian ideas about feminine mental problems. They had hysteria (37).

In 1873 England, Queen Victoria's physician, William Gull, coined the name we use today, anorexia nervosa, which means lack of hunger for psychiatric reasons. The fact that what people with AN can do is incredible was obscured by the view of patients as histrionic. Patients with AN were viewed with distrust and dislike by healthcare workers. This still, to some degree, shapes our attitudes today. The alleged female psychological motives simply changed with the times.

For example, in 1918, Freud wrote, it is well known that there is a neurosis in girls which occurs … at the time of puberty or soon afterward, and which expresses aversion to sexuality by means of anorexia (38). Early in the 20th century, the fear of feeding was attributed to a fear of oral impregnation (39). Crisp thought self-starvation was an attempt to regress to childhood (40). In the 1970s, systems therapists saw the anorexic child sacrificing her health to maintain the equilibrium of a pathological family system (41). By 1980, the dominant explanation was that females wanted to look like thin models and feared getting fat.

It is hard for others to sympathize with them when that individuals with AN are believed to willing to compromise their health to look like models. According to Kelly Vitousek, and her colleagues (42) many clinicians dislike working with anorexia patients because of the perception that clients habitually deny, deceive, and rationalize to protect their symptomatology (p. 392), and anorexics' denial and sometimes defiant stance can adversely affect the therapeutic relationship, and may contribute to punitive treatments, patient abandonment, and intense emotional reactions by professionals (p. 394).

Controlling mothers

In the 1970s and 1980s, the influential psychoanalyst, Hilde Bruch, listened sympathetically to her young patients and wrote rich, precise, and compassionate descriptions in a popular book, The Golden Cage. Although they are starving, Bruch realized, anorexics seemed unaware of that fact. Struck by her patients' apparent sincerity, she struggled to understand why they would refuse food while starving (43).

Bruch noted that patients with anorexia look alike. She wrote, The youngsters came from widely differing backgrounds, but when I first saw them they looked, acted, and sounded amazingly alike … during recovery individual features gradually begin to emerge (p. xi).

A patient named Helga explained, After a certain point, I really felt full. And then you get tormented by this awful guilt feeling after you have eaten any food …. I felt as though a slave driver were whipping me from one activity to the other (p. 21). Bruch wrote, She felt as if an internal dictator were preventing her from satisfying her needs … being helplessly in the grip of a demonic power that controls their life (p. 9).

Bruch quoted another patient (p. 18–19),

My thought processes became very unrealistic. I felt I had to do something I didn't want to do for a higher purpose. That took over my life. It all went haywire. I created a new image for myself and disciplined myself to a new way of life. My body became the visual symbol of pure ascetic and aesthetics, of being sort of untouchable in terms of criticism. Everything became very intense and very intellectual, but absolutely untouchable. If you indulge in being a person who doesn't eat and who stays up all night, then you can't admit, I feel miserable or I feel hungry. Being hungry has the same effect as a drug, and you feel outside your body. You are truly beside yourself—and then you are in a different state of consciousness and you can undergo pain without reacting. That's what I did with hunger. I knew it was there—I can recall and bring it to my consciousness—but at that time I did not feel pain. It was like self-hypnosis. For a long time I couldn't talk about it because I was scared it would be taken away from me.

Although a wonderful observer and reporter of her patients' experiences, Bruch worked during atime when the mind was seen as almost a blank slate and serious mental illnesses were attributed to the family environment. In the 1970s, Bruch found roots of the disorder in her patients' mothers.

It is relatively easy to explain anorexics' misconception and misinterpretation of bodily sensations and experiences. Anorexics were not encouraged during childhood to be honest or accurate in verbal communication or in their view of the world. Instead, they were praised and encouraged to present an artificial front. Consistent