A Comprehensive Guide to Eating Disorders and How to Help
At least 9% of both the U.S. and worldwide populations are affected by eating disorders. Additionally, the illnesses continue to be stigmatized, making it harder for people to seek treatment—which means the number of cases may be higher.
In this piece, we’ll explore many types of eating disorders along with their potential causes and commonly affected demographics, as well as how to tell if you or someone you love needs help—and how to get that assistance.
What Are Eating Disorders?
“Eating disorder” (ED) is a blanket term for a variety of illnesses that greatly affect people’s eating habits and relationships with food. Many, though not all, eating disorders involve a preoccupation with weight as well. Below, we go into the details about many specific diagnoses, some of which simply aren’t discussed enough.
Eating disorders have been around since the beginnings of written history. For example, we know morality and food have been intertwined since at least the 12th century, and symptoms of anorexia—then known as “wasting disease”—were first described by a physician in 1689. EDs began to be recognized in modern ways as medical and psychological issues as early as 1873, and research and treatment have been ramping up ever since.
What is the Difference Between an Eating Disorder and Disordered Eating?
You might hear these terms used interchangeably, but they aren’t the same thing. An eating disorder is a diagnosable mental illness relating to someone’s relationship with food. Disordered eating, on the other hand, refers to an unhealthy relationship with food, fitness, and one’s body.
Disordered eating affects as much as 50% of the population. It can appear as seemingly innocuous as engaging too heavily in a diet plan or as extreme as bingeing and purging but without the medical qualifications for an eating disorder diagnosis. However, disordered eating can open the door to eating disorders, and interventions should be put in place as soon as the challenges are recognized.
What Causes Eating Disorders?
As “eating disorder” is an umbrella term, it’s challenging to develop a concise list of causes—each person’s disorder is unique. Additionally, some oft-reported “causes” are actually correlations, meaning there’s a recognizable connection, but there isn’t yet a proven causal link.
Therefore, just because a characteristic is on this list, it doesn’t mean a person who lives with it will develop an eating disorder or that the issue definitely causes such a disorder. With that in mind, here are some of the issues correlating with or potentially causing many eating disorders:
Autism spectrum disorder (ASD)
Twenty to 30% of adults with eating disorders have ASDs. Studies have shown those with autistic traits that appear before age seven are likelier to develop eating disorder symptoms in adolescence than their peers without these traits.
Those with family histories of eating disorders are likelier to develop them. Specific chromosomal abnormalities have also been seen in people with some EDs.
Interpersonal trauma and post-traumatic stress disorder (PTSD)
People who have experienced abuse, neglect, harassment, or other types of trauma are at higher risk of developing EDs. This is particularly true if the trauma was sexual in nature. PTSD is also a correlate of ED, though not all trauma results in PTSD.
Obsessive-compulsive disorder (OCD)
Many studies have shown people with EDs have higher rates of OCD, and those with OCD have higher rates of EDs—meaning it’s often unclear which came first.
Interestingly, though neglect is also connected to eating disorders, so is enmeshment, or parents’ overinvolvement in their children’s lives. Familial perfectionism and high expectations have also been linked to eating disorders in young people.
Are Eating Disorders Choices or Moral Issues?
The answer is no, on both counts. In fact, it’s essential to remember eating disorders aren’t choices, and food, body size, and morality aren’t related.
People don’t choose to have eating disorders any more than they choose what eye color they’re born with. Eating disorders correlate with or are caused by a combination of genetics, brain chemistry, and outside influences.
Additionally, it’s vital to remember people aren’t “good” or “bad” based on their weight, eating habits, or progress in ED treatment. Connecting morality with weight can exacerbate issues, resulting in extreme weight loss attempts. If treatment is sought, those with eating disorders often feel like they’re morally failing if their conditions worsen. This can cause them to withdraw from loved ones who comprise an essential support system during treatment—because they fear judgment for their perceived “failures.”
It’s important to know these things because eating disorders have the highest death rates of any mental illnesses. Believing it’s a choice or a moral issue—for yourself or someone else—can prevent the desire for or success in treatment.
Who Is Affected by Eating Disorders?
While eating disorders are most commonly associated with young women, anyone can experience an eating disorder. Regardless of gender identity, race, religion, sexual orientation—no matter how one identifies, a person can be affected by an ED at some point in their lifetime.
Types of Eating Disorders
While your high school health classes may have mentioned anorexia and bulimia, there are many types of eating disorders. All types have their own symptoms and causes—however, there are many crossovers between treatment options, which will be addressed at the bottom of this section.
Anorexia nervosa, sometimes shortened to “anorexia” or “AN,” involves a significant restriction in food intake and massive fears about gaining weight or becoming “fat.” The “Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition,” or DSM-V, states people with anorexia find their “self-worth influenced by body weight or shape” and generally don’t recognize their low weight is becoming—or already is—dangerous to their health.
Anorexia is recognized by the DSM-V and is divided into two categories. Signs must have presented within the three months before seeking treatment, though there’s never a bad time to get help.
- Restrictive type: Significantly limiting food intake
- Binge eating/purging type: Eating to excess then purging the food from the body via vomiting or laxatives
Though low body weight previously was a requirement for diagnosis, this is no longer the case. Not everyone with anorexia has low body weight.
Anorexia is diagnosed via a physical exam; lab tests including electrolyte levels and liver, thyroid, and kidney function; and psychological evaluations. Patients may also undergo X-rays to check for bone damage, heart issues, and lung problems; bone density tests; or electrocardiograms to check on heart rhythms.
Signs of Anorexia
Not everyone with anorexia will exhibit all signs, and some may display other symptoms. While many people know to look for signs such as weight loss and restrictive diets, here are other common indicators that a person may be dealing with anorexia:
- Brittle hair and nails
- Exercising to an extreme
- Participating in food rituals
- Use of diet pills, alcohol, or drugs that “increase energy,” such as caffeine or amphetamines
- Weakness and fatigue
- Loss of up to 50% of hair
Sources: Healthline; “Sick Enough” by Dr. Jennifer L. Gaudiani
Causes of Anorexia
Anorexia appears to have a genetic component. Those with family histories of this or other eating disorders seem to be at higher risk. Genomic studies are also beginning to show AN patients’ DNA—particularly in chromosome 12—is different from the norm. Those with AN also often show decreased serotonin and norepinephrine levels.
AN has been connected to increased neuroticism and perfectionism, OCD, schizophrenia, and other mental health disorders. Trauma is also believed to play a role.
Familial attitudes toward weight often influence anorexic behaviors. Pressure from peers, particularly when bullying is involved, also affects one’s possibility of developing anorexia. While not necessarily a cause, there is a correlation between social media and anorexic behaviors.
Effects of Anorexia
Anorexia can have long- and short-term effects on mental and physical health, including, but not limited to:
- Anhedonia (challenges with feeling pleasure)
- Fertility problems and abnormal or lack of menstruation
- Heart disease, particularly bradycardia (slowed heart rhythms)
- Heightened risk of osteoporosis and bone fracturing
- Organ failure and brain damage
- Suicide and self-harm
- Death: Five to 10% of those with anorexia die within 10 years, and 18% to 20% within 20 years—the highest death rate of any mental illness, and 12 times higher than all causes of death for women and girls 15 to 24.
Often called “bulimia” or “BN”, bulimia nervosa involves bingeing and purging. Bingeing is eating an unusually large amount of food—sometimes as much as 3,400 calories in about one hour or 20,000 calories in eight hours—and feeling unable to control these actions. Purging removes this food from the body through tactics including self-induced vomiting; overuse of diuretics, laxatives, or other weight-loss medications; excessive exercise; or fasting.
While this disorder is often associated with a desire to lose weight, this may not always be the primary cause. According to Dr. Jennifer L. Gaudiani in her book “Sick Enough: A Guide to the Medical Complications of Eating Disorders,” “purging can play the role of diffusing anger, sadness, loneliness, or frustration. It can help someone feel numb. It may even bring on a sense of euphoria… [or] be a mode of self-harm, punishing a body that the mental illness insists is unworthy and unacceptable.”
Diagnosing Bulimia Nervosa
According to the DSM-V, a diagnosis for bulimia must include frequent binge eating and purging—at least an average of once per week for three months. However, if symptoms have been occurring for three months or less frequently, you needn’t hold off on getting help.
The diagnosis is divided into two types:
- Purging type: Includes the use of vomiting, laxatives, diuretics, or enemas
- Nonpurging type: Includes the use of fasting or excessive exercise, but not the purging methods above
Dr. Gaudiani notes not everyone who seeks a BN diagnosis will meet all criteria; however, about 20% meet a subthreshold that may be enough to warrant the diagnosis.
BN is diagnosed via a discussion of habits, physical exam, blood and urine tests, electrocardiograms, and psychological evaluation.
Signs of Bulimia
Like anorexia, people with bulimia often display a fear of gaining weight and a preoccupation with body shape—though not always. In addition to those signs, bingeing, and purging, symptoms more specifically related to bulimia include:
- Avoiding social interaction, especially get-togethers that involve food
- Cuts, scars, or calluses on fingers or knuckles, which may indicate induced vomiting (sometimes called Russell’s sign)
- Dehydration, fatigue, and muscle weakness
- Dental problems, such as bad breath, weakened enamel, or broken teeth
- Excessive drinking (including water and diet sodas) after eating
- Frequent trips to the bathroom around mealtimes
- Hiding food
Causes of Bulimia
There is a genetic component to bulimia—if a relative has an eating disorder, it’s more likely someone else in the family does as well.
It’s common for those with BN to have anxiety or mood disorders, histories of sexual trauma, or disorders such as Borderline Personality Disorder (BPD) or OCD. Addiction often is also comorbid or correlated.
Working in a field that focuses on appearances (acting, modeling, etc.) often correlates with bulimia. Undergoing major life changes (divorce, moving, family death, etc.) and experiencing family dysfunction also can play roles. Anything that makes someone feel out of control of their situation, in short, can be correlative or causal.
Sources: “Eating Disorders: Understanding Causes, Controversies, and Treatment” by Justine Reel (book); Eating Disorder Hope; Psychology Research and Behavior Management
Effects of Bulimia
Food intake affects more than one’s weight—it affects the body’s ability to function. Not only can a lack of nutrients hurt the body, but the act of purging can also cause illnesses and injuries, including:
- Damage to the esophagus
- Gastroesophageal reflux disease (GERD)
- Heart arrhythmia
- Rectal prolapse
- Death: Those with bulimia are 1.5 times more likely to die than those without eating disorders.
Binge Eating Disorder (BED) is similar to bulimia in that those living with it eat in excess regularly and compulsively. However, unlike BN, purging doesn’t occur. According to Dr. Gaudiani, it’s common for those with BED to restrict their eating at other times, though it’s not done to balance out the bingeing. The binging almost always involves a sense of embarrassment or shame.
Though anorexia is the deadliest type of ED, and anorexia and bulimia are generally emphasized most in school health classes, binge eating disorder is the most common ED. About 3.5% of women and 2% of men are diagnosed with it, and 11% of women and 7.5% of men show signs of BED.
Diagnostic Criteria for Binge Eating Disorder
To be diagnosed with BED, the DSM-V says people must experience recurrent bingeing (with high food intake occurring over two hours or fewer) and a feeling they can’t help themselves at least one day per week for three months. To seek treatment specifically for BED, a person can’t engage in compensatory behavior like purging or experience AN or BN symptoms simultaneously. If you’re showing any signs of BED, you can still seek help even if you haven’t met the criteria.
The binge eating episodes must include at least three of the following behaviors:
- Eating to excess when not hungry
- Eating until discomfort is felt
- Eating unusually quickly
- Feeling disgusted, guilty, or depressed
- Feeling embarrassed about the amount eaten, resulting in eating alone
BED is ranked on a scale of mild (one to four binges per week) to extreme (14+ episodes per week).
Signs of Binge Eating Disorder
BED may sound easy to recognize due to the frequency of overeating, but it’s actually a very nuanced disorder. While frequent binges should be identified, there are many other signs, including:
- Changing lifestyles to accommodate binges or food rituals
- Fluctuating weight
- Frequent dieting, especially fad dieting
- Hiding foods and food packaging
- Not eating with or in front of others
- Often worrying about weight or shape
Causes of Binge Eating Disorder
Binge eating disorder, like all eating disorders, isn’t a choice. There’s a difference between taking a second (or even third) piece of pie and BED, for instance. Because many people have control over how much they eat, there’s a lack of understanding that leads to an outsized stigma attached to BED. So it’s important to remember this has causes and correlations leading to it, and having the disorder is not a choice.
Mu-opioid and dopamine receptor genes seem to play a role in BED, as do alterations in intestinal microbiota. Additionally, decreased myelination—in which nerve impulses move more slowly—on the gene CYFIP2 has been associated with the disorder. As with most eating disorders, BED patients often have family histories of eating disorders. Long-term stress can also cause the body to release cortisol for too long, which often makes people want to eat more frequently or in larger amounts. Additionally, childhood obesity also is often discovered in BED patients’ pasts.
Perfectionism and a history of abuse have been connected to BED. Body-image issues, mental health impairments, and negative self-image also contribute. The most common comorbidities are specific phobias, social phobias, PTSD, and alcohol abuse/dependence, though depression, anxiety, and bipolar disorder have been frequently discovered as well.
BED symptoms can be reactions to stress. Family members who are judgmental about weight and eating, parents who are often negative, and general family conflict also play roles.
Sources: Boston University School of Medicine; Eating Disorder Hope; Mayo Clinic; StatPearls
Effects of Binge Eating Disorder
While it would be easy to assume weight gain is universal in people with BED, Dr. Gaudiani states, “Not everyone with BED is in a larger body, and not every person in a larger body has BED.” While weight gain can be an effect of BED, there are many others, such as:
- Brittle hair and hair loss
- Constipation and IBS
- Gallbladder and liver disease
- Polycystic ovary syndrome (PCOS)
- Ruptured stomach
- Sleep apnea
Sources: StatPearls; Mayo Clinic; The Emily Program; Eating Disorder Hope
Pica is an interesting disorder because it generally has no ties to body image or self-esteem. It’s often short-term—though not always, especially if the patient has comorbid disabilities or mental health issues.
Also, unusually, it tends to “target” specific populations, particularly children or pregnant people—though anyone can be affected. It’s estimated 10% to 30% of children between the ages of one and six experience pica. Numbers in pregnant people (and those above age six in general) are harder to ascertain because many don’t report due to embarrassment.
A person with pica has a compulsive need to eat nonfood items that aren’t part of their cultural norms or aren’t developmentally normal (e.g., small children putting things in their mouth). While the compulsion can apply to any nonfood item, access is key—people with pica don’t tend to seek out things that are difficult to find. Some of the common nonfood items are:
- Dirt, clay, or pebbles
- Hair (sometimes due to comorbidity with trichotillomania)
- Talcum powder
Some products considered semi-food may also be involved, like gum, starch, or baking soda, the latter of which can be especially dangerous.
Diagnostic Criteria for Pica
As per the DSM-V, for pica to be diagnosed by a mental health professional, the following must be true:
- The person has consistently ingested nonfood items for at least one month.
- Signs must not be developmentally appropriate.
- This behavior can’t be encouraged by cultural or social norms.
- If it’s comorbid with other conditions such as intellectual/developmental disabilities, ASD, schizophrenia, pregnancy, or other eating disorders, the pica alone must be severe enough to allow individual medical intervention.
In addition to mental health professionals, obstetrician/gynecologists, pediatricians, and other doctors can also spot signs of pica and treat those symptoms—though they’ll likely refer the patient to a therapist or psychiatrist if they meet the criteria above.
With pica, the onus may often be on the patient to tell their healthcare provider about their eating behaviors. Otherwise, the medical professional may only see vitamin deficiencies and other effects and scramble to find a cause—delaying appropriate interventions.
Signs of Pica
In addition to the compulsion to eat nonfood items, other signs of pica people may notice include:
- Bloody stools and other bowel problems
- Nausea and stomach pain
- Tooth and mouth damage
Causes of Pica
Nutrient deficiencies are a major cause—the brain is trying to fill those gaps with things it thinks may have what the body needs. A family history of pica may also play a role.
While pica often exists on its own, intellectual/developmental disabilities (especially ASD), mental health issues such as OCD, schizophrenia, trichotillomania, and excoriation disorder, and other eating disorders—particularly those that involve food restriction—are often comorbid. Sensory-seeking behaviors may also play a role, as may stress.
Living in situations where food is scarce may cause pica. Abuse and neglect are often seen among patients as well. Additionally, while the diagnostic criteria state the consumption can’t be culturally accepted, these norms can escalate to a need for intervention if health problems begin or the behavior becomes compulsive rather than situational.
Sources: Healthline; Medical News Today; Rady Children’s Hospital; StatPearls
Effects of Pica
While pica, over the short term, often doesn’t have major consequences (depending on what’s ingested), long-term pica can have dire consequences, including:
- Brain damage
- Infections and parasites (especially if feces are ingested)
- Intestinal, stomach, and bowel blockages or tears, sometimes requiring surgery
- Lead poisoning
- Vitamin and nutrient deficiencies, especially anemia
- Death due to any of the above effects of pica
Sources: Healthline; Healthy Place; Medical News Today; Rady Children’s Hospital; StatPearls
Many people are picky eaters, but avoidant/restrictive food intake disorder (ARFID) takes pickiness to an uncontrollable level. While picky eaters can usually “tough it out” through foods they don’t like, those with ARFID almost universally can’t bring themselves to touch certain foods. Additionally, those with ARFID may show legitimate fear of foods or total disinterest in eating.
Diagnostic Criteria for ARFID
Previously, ARFID was only recognized if symptoms began before age six. However, the DSM-V removed that requirement when they updated criteria to include the following:
- Eating or feeding disturbance resulting in nutritional or energy deficiencies, with at least one of the following being evident: large weight loss or not meeting age-appropriate weight goals; nutritional deficiency; needing nutritional supplements or feeding tubes; psychosocial challenges
- No challenges with obtaining food and no relevant cultural norms/expectations
- Existence outside of bulimia and anorexia and no evidence of major concerns about weight or shape
- Can’t be caused by another medical condition or mental disorder unless the ARFID symptoms are severe enough to require separate treatment
Signs of ARFID
ARFID and picky eating are hard to distinguish at first glance, especially in children. For instance, both picky eaters and those with ARFID may have short lists of foods they’ll eat. However, some important differences to note are that while picky eaters seldom experience the following, those with ARFID usually do:
- Discomfort with specific food-preparation methods
- Extreme fear of or anxiety about certain foods
- Inability to eat in social settings
- Refusal to try new foods or reintroduce foods into their diets
- Requirement of nutritional supplements (Ensure, Pedialyte, etc.) or feeding tubes
- Total or near-total lack of interest in food—most “picky eaters” want to eat, just not specific foods
- Unexpected and high weight loss, including children not meeting developmental goals
- A very short list of edible foods, including the elimination of categories based on factors such as color, texture, or food group
Sources: Center for Discovery Eating Disorder Treatment; Walden Behavioral Care
Causes of ARFID
Biological causes Those with family histories of eating disorders are more likely to develop ARFID. Food allergies and gastrointestinal problems are often present.
Psychological causes Developmental disabilities such as ASD and anxiety disorders are often comorbid. Unchecked picky eating from childhood may also contribute.
Environmental causes Pressure to eat healthfully or a focus on where foods come from (processing methods, animal treatment, environmental impacts, etc.) can lead to ARFID. Trauma, abuse, and neglect may also play roles—especially if the trauma is food-related, like a choking incident.
Sources: Center for Discovery Eating Disorder Treatment; Eating Recovery Center; VeryWellMind
Effects of ARFID
While picky eating may be an annoyance, it usually doesn’t go beyond that—ARFID does. Problems caused by ARFID include:
- Bone-density reduction and osteoporosis
- Brittle nails and hair loss
- Nutritional deficiencies that may require medical intervention such as feeding tubes
- Stunted growth
- Organ failure and heart problems that could lead to death
Sources: Eating Recovery Center; Monte Nido
OSFED, an acronym for “other specified feeding or eating disorder”, is a catch-all term for eating or feeding issues that don’t fit perfectly into specific diagnoses. Symptoms may line up with a particular disorder, but perhaps they haven’t lasted the required amount of time for that diagnosis, for instance. Or there may be a combination of disordered-eating symptoms that are clearly affecting one’s life but don’t fit into a specific diagnostic box.
Some conditions that may fit into this category—a few of which are slang with no official medical terminology—include:
Unspecified feeding or eating disorders (UFEDs) differ from OSFEDs in one way: The medical professional doesn’t specify why a patient doesn’t mean the criteria for a specific eating disorder. This usually means there isn’t enough information yet, and those diagnosed with UFED may be recategorized.
Diagnoses That Resemble Eating Disorders
Some ailments may sometimes resemble eating disorders but aren’t—though they still need medical intervention. They include, but aren’t limited to:
- Body dysmorphic disorder
- Celiac disease
- Cyclic vomiting syndrome (CVS)
- Food addiction
- Food allergies (though studies show there may be a connection between these and EDs)
- Klein-Levin syndrome
- Muscle dysphoria (“Bigorexia”)
- Prader-Willi syndrome
Common Eating Disorder Treatments
Treatments vary somewhat based on the type of disorder—especially medical options, as opposed to psychological ones. However, many treatments are used more or less across the board:
Acceptance and commitment therapy (ACT)
Encourages patients to focus on actions rather than emotions, accept emotions as reality, and find ways to overcome the roadblocks they face
Cognitive behavioral therapy (CBT)
Talk therapy, sometimes including exposure therapy, in which the patient is exposed, in a safe setting, to the objects or circumstances that make them uncomfortable or fearful
Cognitive remediation therapy (CRT)
Supervised exercises targeting specific skills, like memory and attention, to help avoid or undo executive functioning damage that can be caused by malnourishment
Dialectical behavioral therapy
One-on-one or group therapy method focusing on mindfulness, ability to tolerate distress, and emotional regulation and interpersonal skills, with homework to continue skill-building outside of therapy sessions
Occurs when medical complications arise; can resemble residential treatment or lead to it if needed
Interpersonal psychotherapy (IPT)
Short-term therapy focusing on social skills, including in-person sessions and homework assignments
Working with a dietician or nutritionist to create appropriate meal plans and understand healthy eating habits
Use of medications to treat ailments; medications vary by disorder but can include SSRIs, antidepressants, anti-seizure drugs, ADHD medications, and medications related to specific health issues like diabetes
One of the oldest types of therapy, focusing on how the past influences the present and how unconscious feelings can affect daily life
Residential or day treatment
Treatment in which the patient spends 24 hours a day or several hours per day in a treatment facility, respectively
Who is Affected by Eating Disorders?
Simply put, no population is immune to eating disorders.
For all groups, genetics and comorbid mental illnesses play roles. However, different communities experience other causes at varying rates. Additionally, any of the groups can have any eating disorder, but some are more common among certain populations than others.
Below, you can find information about how different groups of people are affected by eating disorders.
Eating Disorders in Children
It’s been reported that 20% to 50% of 8- to 13-year-olds are dieting. According to Karen Lombardi, Ph.D., and her fellow researchers in the Health Promotion Journal of Australia, body image begins to develop around age three, and anorexia has been seen in children as young as seven.
Unlike older people, children with eating disorders aren’t as likely to express fear of “being fat.” Additionally, boys are more likely to be affected. These discrepancies between the usual understanding of eating disorders and how they present in children can make them hard to diagnose.
Most common eating disorders in children
ARFID, pica, anorexia
Causes/correlations of eating disorders in children
Chronic illnesses, family influences, social pressures
Sources: Johns Hopkins Medicine; Lombardi et al.; Psycom
Eating Disorders in Teens
Until about age 13, boys and girls report similar rates of body image issues. At 14 or so, the groups begin to diverge, with girls’ body images statistically worsening while boys’ improve—though this doesn’t mean teenage boys are immune to EDs. It’s important to recognize teens aren’t engaging in eating disorder behaviors for attention—no matter the age, these are legitimate struggles that need to be addressed.
Most common eating disorders in teens
Anorexia, bulimia, binge eating disorder
Causes/correlations of eating disorders in teens
Peer and family pressure, societal messaging, participation in activities (sports, dance, etc.) with a heavy focus on weight/size, major life changes
Sources: Mayo Clinic; Polaris Teen Center
Eating Disorders in Adults
While the causes and types of EDs in those in their 20s are similar to those for teens, midlife adults—between ages 35 and 55—experience EDs a bit differently. According to Bethany Bryan, author of “Dealing With Eating Disorders,” about 3.6% of women between 40 and 50 and 13% of those over 50 display eating disorder behaviors. Additionally, between 0.2% and 1.6% of men between 45 and 59 go through eating disorders in any given year. Some adults with EDs had them earlier in life, but not all.
Studies tend to focus on younger age groups, so there’s every chance this population’s rate is underreported.
Most common eating disorders in adults
OSFED, binge eating disorder, bulimia, anorexia
Causes/correlations of eating disorders in adults
Natural hormonal and bodily changes, relationship issues, family death, caregiving for parents, increases in illnesses, and other life changes
Eating Disorders in the Elderly
We tend to think of eating disorders as only affecting young people or, when older people struggle with eating, we often attribute it to aging, forgetfulness, or new food sensitivities. However, older adults can have eating disorders—even without a history of them.
Many long-term care facilities aren’t equipped to handle—or even recognize—eating disorders, so families need to keep an eye out. Challenges in long-term care are exacerbated by the fact that laxatives are readily available and handed out often, giving people who purge the means to do so.
Most common eating disorders in the elderly
Anorexia, bulimia, binge eating disorder
Causes/correlations of eating disorders in the elderly
Attempts to avoid weight-related medical problems, damaged teeth or ill-fitting dentures, changes in their bodies as they age, life transitions, and loss of loved ones
Sources: Eating Disorder Hope; Monte Nido
Eating Disorders in Cisgender Boys and Men
Unfortunately, very few eating disorder studies—less than 1%—focus on men. Additionally, sometimes men are not allowed to go to treatment centers as they’re often female-only. Society and medical professionals are also less likely to recognize the signs in men. Historically, diagnostic criteria have been heavily biased against men being diagnosed at all.
When looking at data relating to cisgender males and eating disorders, we need to remember the numbers may be off. When research is lacking, existing figures could be inaccurate. However, based on current estimates, about 10 million males will have an ED at some point in their lives; they comprise 15% of those with AN, BN, and BED, and about 22% resort to dangerous methods to become more muscular.
Most common eating disorders in cisgender boys and men
Binge eating disorder, bulimia, anorexia, muscle dysmorphia*
Causes/correlations of eating disorders in cisgender boys and men
A desire to be more muscular, participation in sports focusing on weight, substance abuse, family influences, stress, treatment avoided due to increased stigma
*Muscle dysmorphia isn’t technically an ED, but it shares many of the characteristics and is possibly the most common ED-like condition among men.
Sources: Center for Change; VeryWellMind; Psycom
Eating Disorders in the BIPOC Community
When someone imagines a person with an ED, chances are they think of a young, white girl—after all, that’s what most of us saw in our health textbooks. But just as males and older people can be affected by EDs, so can members of the Black, Indigenous, and People of Color (BIPOC) communities.
And just as with those who aren’t young and female, EDs in BIPOC populations are understudied. When they’re included, as one resource points out, some of the diagrams used—which are meant as visual means for identifying similarities to one’s own body—feature only light-skinned bodies. This could easily cause discrepancies between actual body image and what’s reported by study participants, as people may not be able to “see themselves” as easily in the images.
About two million BIPOC women in the U.S. will likely experience eating disorders in their lifetimes. Black teens are 50% more likely to purge than white ones, and Latinx people are more likely to deal with bulimia than non-Latinx people. Indigenous people are the least likely to be included in studies—leading us to almost no data (Bryan, p. 31). Perhaps most alarmingly, BIPOC individuals who admit to having disordered eating or weight concerns are less likely to be asked about these symptoms by their doctors than white people are.
Most common eating disorders in the BIPOC community
Bulimia, anorexia, binge eating disorder
Causes/correlations of eating disorders in the BIPOC community
Stress from microaggressions and other forms of discrimination, food insecurity and poverty, social expectations, trauma
Sources: F.E.A.S.T.; More-Love.org; National Eating Disorders Association
Eating Disorders in the LGBTQ+ Community
Eating disorders hit LGBTQ+ people at much higher rates than they do cisgender, straight people. This is demonstrated in the following:
- Nonbinary and transgender people experience anorexia and bulimia four times more often than cisgender people, and about 16% of transgender people in one study had diagnosed eating disorders (Bryan, p. 30-31).
- Among men with eating disorders, 42% identify as gay.
- Women who don’t identify as straight were found to have binged at least once per month in a given year.
LGBTQ+ people have challenges in receiving treatment that many other groups don’t. For one, many professionals aren’t trained in the unique health and social issues people in this community face. Secondly, due to discrimination, there may not be anyone who notices they’re struggling or to whom they feel comfortable talking. And a third factor—though there are many—is the high rate of homelessness. If you’re homeless, you likely don’t have easy access to medical care or food, plus you may feel out of control—and eating is something you can control to a certain extent.
Most common eating disorders in the LGBTQ+ community
Bulimia, binge eating disorder
Causes/correlations of eating disorders in the LGBTQ+ community
Experiencing discrimination and fear of rejection, trauma, differences between one’s body and one’s identity, internalized biases, homelessness
Source: National Eating Disorders Association
Is Social Media Affecting Eating Disorder Rates?
People are quick to blame social media for eating disorders—but are the two actually linked?
The first thing to remember is that correlation isn’t causation. Eating disorders are mental illnesses, and just like schizophrenia or bipolar disorder, you can’t “catch” an eating disorder from a computer screen.
However, there is evidence that social media use influences eating habits, body image, and more, which can affect the rate of eating disorder diagnoses, especially for those who are predisposed to developing EDs. This is possibly because, like many mental illnesses, eating disorders can be “triggered.”
When talking about the onset of mental illness, a “trigger” is the event or situation that flips the switch from off to on. It doesn’t have to be a single event—living in a negative situation can be a trigger. Not everyone with a predisposition for eating disorders will develop one, even if they spend all day on social media—but some people do say social media flipped that switch for them.
The types of social media and the people with whom one engages on these sites play roles in body image and ED issues.
Photo-based social media platforms, such as Instagram, seem to have the biggest effect on EDs:
- 49% of UK Instagram users studied show signs of orthorexia nervosa (extreme “clean” or “healthy” eating), compared to less than 1% of the overall population.
- Those who follow healthy eating Instagram accounts are the most prone to these signs.
There is a well-intentioned #bodypositive movement on many social media sites, aiming to make people of any size feel good about how their bodies look. Some people are helped by this. Others are negatively affected by the #bodypositive movement because they feel left out of the conversation or stigmatized if they don’t feel positive about their bodies 24/7. In respose, many are working toward a #bodyacceptance movement instead, which focuses on all the great things your body can do rather than how it looks, with the goal of allowing you to feel how you feel and find a way to maintain a healthy balance.
So do social media and internet usage cause eating disorders? There isn’t any causal evidence like there is with other things like family histories. However, there’s clearly a correlation for those who are already likely to develop EDs.
“I deleted tiktok from my phone because it was having an effect on my body image and exercise and eating,” said an 18-24 year old man in a UK study. But just deleting an app—especially if it’s one you connect with real-life friends on—isn’t always as simple as clicking the trash can button. That should be acknowledged, especially in a world where social media addiction is becoming more recognized.
As hard as it can be, at the very least, attempt to unfollow hashtags and influencers who make you feel bad about yourself. If your friends bring these topics up, try to ask them to stop or change the subject.
What to Do if You Think You Have an Eating Disorder
According to the preface in Dr. Gaudiani’s book “Sick Enough,” “Patients with eating disorders frequently feel that they aren’t ‘sick enough’ to merit treatment, despite medical problems that are both measurable and unmeasurable.” So if you’re hesitating about getting treatment because you believe you’re not “sick enough,” you’re not alone.
But waiting until you’re sick enough could have long-term consequences for your mental and physical health. Just as you aren’t likely to wait to get help with a broken leg, you shouldn’t hold off on getting help with eating disorder symptoms.
This isn’t to say it’s easy. For most people, it’s not. You aren’t stupid or bad for not immediately recognizing a challenge or going to a doctor. There are internal and external hurdles to overcome, societally, emotionally, and possibly financially. You may also find it hard to get a doctor who takes you seriously. But don’t give up! Those good doctors and support systems are out there. You can do this.
A great place to start is the National Eating Disorders Helpline, where knowledgeable people are standing by to talk to you via chat, text, or phone every weekday, and you can leave a message if they’re unavailable. These people can help find you find treatment, support groups, and other resources—as well as serve as someone you can talk to. More resources can be found at the bottom of this page.
What Mental and Physical Healthcare Professionals Can Do to Help
Doctors, nurses, mental health professionals, and all other healthcare workers are likely to encounter people with eating disorders during their careers—whether or not they specialize in this area. And just as it’s intimidating for those with EDs to seek medical care, it can be intimidating to treat someone with EDs if you don’t have the background knowledge.
However, some specialize in this field. “Clinicians who are drawn to this field have huge hearts, care deeply, and want the best for their clients. They often need to advocate for their clients and do so best when they know more about what is going on medically,” says Gaudiani (p. 5). So whether you work in physical or mental health, it’s essential to communicate with anyone on a patient’s medical team to get a full picture.
It’s also important to be aware of patients’ limitations—especially financial and logistical ones. According to Gaudiani, “There are, it must be noted, serious ethical problems with recommending what care patients ‘should’ receive, when in many cases there are inadequate resources to access this care” (p. 7). Learn about free and low-cost resources in your area and be ready to advocate for your patients to specialists and insurance companies.
This section discusses the challenges mental and physical health professionals have with treating EDs, the issues that cause patients concern, and how to handle these topics.
Mental Health Professionals and Eating Disorders
Mental health professionals are there to help people get through whatever challenges life throws at them.
However, even those working in this field aren’t invulnerable to weight biases. A study out of Yale University showed that 88% of eating disorder specialists surveyed feel confident in treating obese patients. However, 84% feel prepared to do so, and 56% said they’d heard their peers—those in their same field—say negative things about people with obesity. Many felt their peers held negative biases against people in larger bodies, believing stereotypes about poor choices. The observed that such biases led to worse outcomes for those clients.
Even the best mental health professional is still human, and no person is free of biases. But those in this field need to work toward shedding these feelings—it can be a matter of life and death. If you find yourself having negative thoughts about people’s weight, try to reframe the internal conversation.
Mental health professionals also need to make sure they’re the best fit for their clients. One study found typical concerns ED patients had regarding their therapists or other such specialists were:
- Ability to relate
- Ability to communicate or connect
- Knowledge of EDs
- Rapport, or how the therapists react to them
- Understanding of pressures females face
Though at lower rates, other concerns they had were feeling supported and having male therapists (versus females) when addressing these issues.
Just as a person with an ED hasn’t failed by having the disorder, a mental health worker hasn’t failed by recognizing they may not be the fit for a patient. Referring them to someone else can be hard, but if you truly believe it’s in the patient’s best interests, it may be time to open that conversation. People with EDs often need to work with specialists on those issues.
Additionally, try to ensure your client has consented for you to consult with their other doctors, including their general practitioners. You can’t force them to agree to this, of course, but if they haven’t signed off on such a consultation, it’s important to dig into their concerns. Do they not trust the other doctor? Are they worried about health insurance? Are they embarrassed for someone else to know? Once you know why, use your understanding to direct them to make a choice you think is most helpful, whether that’s considering a new doctor or agreeing to the consultation—but if they refuse, don’t push. They need to trust you.
What Role Do Social Workers Play in Eating Disorder Treatment?
While the average person may think of social workers as people who focus on child protective services, those in the field know they do much more. And they can be essential for people who are living with eating disorders.
Perhaps most importantly, social workers often have resources other mental and physical health practitioners don’t. A large part of their job is finding resources for clients. As mentioned above, there are ethical issues in determining the right kind of treatment for patients, especially those with financial or other limitations. Social workers are there to find treatment they can access more easily.
However, social workers may receive basic training in eating disorders, but their knowledge isn’t always complete. For instance, a study of 12 Master of Social Work students showed there was little to no understanding of effective treatment of BED in adult women, with nine of the students surveyed acknowledging there needs to be more training in this disorder.
If you’re a social worker or social work student and find you don’t have adequate training in this area, you should try to obtain additional training for yourself. No matter what your focus is, you’re almost definitely going to encounter a client with an ED, and you need to be able to handle their needs with confidence when planning a course of action.
Medical Professionals and Eating Disorders
No medical professional wants to make people feel unwelcome or bad about themselves, but it’s common for this to happen.
Dr. Gaudiani discusses this in “Sick Enough,” explaining that doctors are at least as prone to having internalized weight biases as other people are— if not more so (p. 133). However, she also recognizes why this happens. Her own medical training focused on how heavier weights can lead to health problems, losing weight can mitigate health problems…and that’s it. She received no training on the social factors involved with body image. She believes this led her to inadvertently harm her patients, truly thinking what she was doing was best.
Gaudiani’s observations are backed up by other studies; many doctors and other medical professionals simply feel unequipped to handle eating disorders.
She goes on to talk about the challenges people in larger bodies face when getting medical treatment. Because of weight biases, many with EDs—or anyone of “imperfect” weight—avoid going to the doctor at all. Dr. Gaudiani states such patients frequently report doctors focusing on weight instead of addressing why the patient visited the doctor in the first place. She also says many feel unwelcome, unable to fit in chairs or examination gowns, which leaves them feeling both literally and existentially exposed. Additionally, the BMI charts on the walls serve as constant reminders of how they’re viewed.
An anonymous woman in the 25- to 34-year-old age group in a study by the UK House of Commons stated, “We need to consider the way our medical professionals also talk about our bodies. I’ve never recovered from a GP telling me they could see how overweight I was just from me sitting in front of them (she then pointed at my arms and made a hefty gesture). I was 8lbs overweight and just 22 years old. This was 10 years ago and I’ve never been to the GP since.”
Therefore, it’s essential that medical professionals seek additional education about societal, medical, and psychological issues that could influence weight and, especially, how to talk to people in larger bodies. Avoid words such as “fat” unless you’re talking about the actual food group.
It’s also important for members of medical teams to keep each other in line. This can be hard, especially if you’re at a more junior level than the person you see engaging in negative behaviors. If a patient is present and the healthcare worker they’re talking to begins to focus on their weight—especially if the patient is in the office for something unrelated—gently nudge the practitioner back to the topic at hand. If you attend training about this issue, share what you learn with others, and encourage your facility’s manager to incorporate professional development on these topics as well.
What Family Members and Friends Can Do to Help
Eating disorders wreak havoc not just on the people living with the disorders but also on the lives of their loved ones. It’s terrible to watch someone you care about go through something like this. But it’s possible to help them and, along the way, help yourself.
While no one plans for their child, spouse, or friend to have an eating disorder, steps can be taken to potentially prevent such disorders before there’s even a hint of a problem—and these steps generally boil down to simply being kind in your words and actions. It comes down to reframing the way you speak and act.
Instead Of That, Do This…
Don’t: Talk about others’ weight or size as if they’re choices or moral issues.
Do: Refuse to engage in “fat talk” and call people out when they do it.
Don’t: Ignore traumas your loved ones may have faced, especially by telling them to “get over it.”
Do: Follow their lead about whether they want to talk, and help them find mental health assistance without judgment.
Don’t: Say you’re “just worried about their health” when talking about weight, especially if you don’t know anything about their health other than what you can see.
Do: Avoid saying anything because, “You cannot tell who has an eating disorder or who is healthy or unhealthy just by looking at them” (Gaudiani, p. 129).
Don’t: Talk about those with eating disorders negatively. For example don’t suggest they “just aren’t showing enough willpower.”
Do: When eating disorders come up, talk about how they’re mental illnesses, and say people who fight them are acting bravely.
Don’t: Criticize what’s on someone’s plate by saying, “Are you sure you want to eat that?” and similar comments.
Do: Offer healthy choices for food. If you’re the parent or primary cook, learn about nutrition and plan meals accordingly—and eat them yourself as well—without comment.
Don’t: Say “You look great/terrible/fat/thin/etc.”
Do: Compliment achievements (work, school, etc.) and other traits not related to their physical selves.
Don’t: Encourage people to “keep it up!” when they’re losing weight, as it implies they aren’t doing enough.
Do: Say nothing unless they bring up the weight loss, and in that case, say something supportive but noncommittal, like “I’m glad you’re happy.”
Don’t: Use the words “fat,” “overweight,” or “obese” to describe people.
Do: Avoid commenting on people’s weights in general, but if you need to use a term, adopt “people in larger bodies.”
Now you may not have said or done any of the “don’ts,” and your loved one may still have ended up with an ED. Or maybe you did engage in them without meaning any harm. Playing the blame game helps no one, so step back, take a deep breath, and focus on the problem at hand rather than on the past.
However, if you’re feeling guilty or are the caretaker of someone with an ED, find help for yourself first. Like oxygen masks on airplanes, you need to make sure you can “breathe” before you can help someone else do so. If you’re spread too thin emotionally, you can’t support another person well. Find some therapy or contact the National Eating Disorder Helpline—it’s not just for those with EDs.
If you suspect someone has an ED, don’t ignore it—but also don’t come in with guns blazing. Find a peaceful time and open the conversation
The Center for Change recommends starting with concern, a desire to help, and the opportunity for the other person to explain or refute your observations. Be honest and specific about what you’ve observed and why it worries you, ensure your loved ones that you’re here for them, and stress that this won’t change your relationship. Ask them to get help, even if they don’t admit there’s a problem. For instance, you could say something like, “I hear you and understand. But please make an appointment with your doctor, just to make sure everything’s okay.”
Below, you’ll find more specific information for parents of young children, parents of adult children, and friends of those with EDs. But no matter which category you fall into, remember this: A person is not a disorder. The disorder is something they have, not something they are. Make sure they know you still see them, not just the thing they’re going through.
Options for Parents of People with EDs
Eating disorders can affect people of all ages, and it’s essential to know the signs and what you can do to intervene for your child— regardless of how old they are. The National Eating Disorders Association has a Parent Toolkit that may help guide you.
If you’re the legal guardian of a minor whom you believe has an ED, remember: While you’re in charge of many things, you can’t force someone to not have an eating disorder. You can, however, bring your child to a doctor’s appointment and ensure the doctor knows why ahead of time. This may not be easy, especially if your child is resisting, but find a way to get it done using kindness and calmness, not anger and threats.
Many parents don’t realize that while most school staff want to help, they may not be able to. Children could admit there’s a problem to a teacher first—but teachers aren’t always allowed to pass the information along to parents. Conversely, if you report this to a school principal or nurse, the teachers may not be told. All of this comes down to complicated privacy laws.
If you’re in the latter situation, as hard as it may be, contact each teacher individually—even if you already indicated that the information could be passed along, it may not be, especially if that permission is not in writing. Information may also get lost in translation, and it’s best if it comes directly from you. Share the information, including their symptoms and treatment plan, and advise them on what you need. Be open to answering questions.
Consider arranging a meeting with all of the child’s teachers, as well as an administrator, nurse, and school counselor, so you can figure out a plan together—for instance, if your child is purging, bathroom restrictions and escorts between classes may be necessary. If possible, have your child be a part of the conversation. You may even want to take it a step further and work toward a 504 plan, which is a binding plan regarding how your child’s needs will be met.
But what if your child is over 18? You still have options, including:
- Identifying and using any leverage you have
- Being granted medical guardianship and/or conservatorship
- Calling 911 in an emergency, which may result in a 72-hour hold, after which a judge decides what needs to happen
No matter what, though, lead with love and make sure your child knows you’ll still be there for them.
A Special Heads Up for Parents
A study in the journal “Health Communication” referred to statements about how people look that are remembered years later as “memorable body messages.” These statements most commonly came from participants’ mothers, though they were heard from people all around them. Of the participants, 43.1% said the statements—from anyone—were about body size, and only 12.2% stated they were about appreciating their bodies.
At the extreme ends, a couple of these messages were:
“[M]y mom always told me, ‘its better to be depressed skinny than fat.'”
“[M]y mom always made sure that we as children felt beautiful for being just the way we were. She didn’t force me to look like the barbies I saw on T.V., which a lot of moms did to their girls.”
Options for Friends of People With EDs
While friends don’t have the same leverage as parents, they’re an essential part of the support group for someone working through an eating disorder.
In addition to opening the conversation and encouraging the person to see a doctor, as mentioned above, you can also support them in other ways.
If you’re a student, talk to your school counselor or nurse. They will keep information about who came to them with concerns confidential. You could also talk to your friend’s parents, if that feels safe, or talk to your own parents so they can help you figure out what to do.
It’s scary to talk to a friend about things like this, and you might be afraid of losing the friendship. That’s totally understandable, and we can’t promise that won’t happen. But at the end of the day, remind yourself it’s better to have a former friend who’s safe than a current friend who isn’t.
While it may seem contradictory, remember that no matter what happens — whether you spoke up or not — someone else’s mental illness and its results aren’t your fault.
Things can be even more complicated for adults. You don’t have a school counselor to go to, and you may not even know your friend’s family—though if you do and you feel they would be safe to talk to, you can certainly bring your concerns to them.
It may sound simple, but the best thing you can do is be a good friend. Never judge them. Don’t comment on their weight. If they’re in treatment, find out how you can make sure they don’t feel forgotten, even if they’re in inpatient care. Remind them you’re there, no matter what, and that eating disorders are treatable. This can be a hard balance to strike, as you want them to know you believe in them and that you also won’t be mad if they make a mistake—but, as you know your friend, you can likely find a way to strike this balance.
Helplines for Those with EDs and Their Loved Ones
These helplines can talk you through crises, provide assistance in finding resources, and more. Most options allow you to be anonymous if you choose.
NEDA Helpline (eating disorders only)
Monday-Thursday, 11 AM to 9 PM EST
Friday, 11AM to 5 PM EST
Text Monday – Thursday, 3 PM to 6 PM EST
Monday – Thursday, 9AM to 9PM EST
Friday, 9AM to 5 PM EST
ANAD Helpline (eating disorders only)
Monday – Friday, 9 AM to 9 PM CST
Crisis Text Line (any type of mental health crisis)
Text 741741 (US and Canada)
Text 85258 (UK)
Text 50808 (Ireland)
Chat Online on Facebook (Not Anonymous)
Diabulimia Helpline (for diabetes combined with EDs, depression, anxiety, PTSD, OCD, and burnout)
National Suicide Prevention Lifeline (suicide prevention hotline)
Information About and Help With Eating Disorders
General Organizations and Journals
National Eating Disorders Association (NEDA)
NEDA is the largest nonprofit dedicated to helping people and families dealing with eating disorders. They have a screening tool to see if you may have an ED (does not replace a medical evaluation), information about free and low-cost assistance, details about recovery and relapse, and other resources. NEDA recently merged with the National Association for Males with Eating Disorders (N.A.M.E.D.), allowing them to provide better information for members of that community.
National Association of Anorexia and Associated Disorders (ANAD)
The oldest organization focusing on eating disorders in the U.S., they help individuals, schools, families, and communities understand and fight eating disorders. They aim to help people find support groups and treatment, train loved ones to be grocery shopping buddies, and provide a wealth of other information.
The Alliance for Eating Disorders Awareness
This national organization can help find treatment and support groups, provide information for loved ones of those with EDs, and have a blog about all sorts of topics in the ED world.
Eating Disorders Coalition (EDC)
This group fights for eating disorder awareness and treatment at a policy level.
Eating Disorders Review
This journal provides information about diagnosis and treatment of eating disorders, focusing on practical and readable information for everyday life.
Support and Treatment
This group focuses on diabulimia—EDs combined with diabetes—and provides resources for those living with it, their loved ones, and medical professionals. They can help find treatment centers, run support groups, and more.
Eating Disorder Hope
This organization can help find eating disorder treatment, offers online support groups for BED, AN, and BN, and other education and awareness resources.
Eating Recovery Center
Though this is a treatment center, you don’t need to seek treatment through them to access their vast number of other resources for patients, families, and professionals.
Project Heal works to help those with EDs who are struggling to access treatment. They can help you understand and navigate health insurance issues and find free treatment options, as well as provide one-time cash assistance to those in need.
Trans Folx Fighting Eating Disorders (TFFED)
This collective is run by transgender and gender diverse people fighting to recognize EDs in marginalized communities as social justice issues. They offer several support groups and a list of TFFED-approved practitioners, train providers in issues unique to this demographic, and run a blog written by people in the community.
Help for Loved Ones
Families Empowered And Supporting Treatment for Eating Disorders (F.E.A.S.T.)
This organization is run by parents for parents of those with EDs. They provide various programs and services, including ways to talk with other parents about what you’re going through.
This organization exists to help parents teach their kids to appreciate their bodies, avoid disordered eating and eating disorders, and learn to deal with any fear or shame they may have while their children struggle with these issues.
Books About Eating Disorders
We’ve included Amazon links to the books below. However, don’t forget about your local library, where you can borrow these books for free. If they don’t have your chosen book in stock, contact their interlibrary loan team to see if they can get it for you.
Dealing With Eating Disorders by Bethany Bryan
This short book includes detailed information about eating disorders and their diagnoses and treatments, as well as about what it’s like to live with one. It’s best for those in middle school and older.
Sick Enough: A Guide to the Medical Complications of Eating Disorders by Jennifer L. Gaudiani, MD, CEDS, FAED
This was written for clinicians and discusses all manner of eating disorders, how to best communicate with patients, and what the medical community needs to do to improve. However, it’s also an excellent resource for anyone interested in the topic because it is comprehensive and readable.