Understanding Eating Disorders

Eating disorders are psychiatric illnesses with profound medical consequences — not lifestyle choices, vanity, or a lack of willpower. They carry some of the highest mortality rates of any mental illness, through both medical complications and suicide. They are also deeply treatable, and early recognition changes outcomes.

They sit on a spectrum and reach across every age, gender, race, culture, and body size. The behaviors — restriction, bingeing, purging, compulsive exercise — can appear in many combinations and can shift over time within the same person.

• ·Look past the scale to behaviors (rules, rituals, avoidance), vital signs, labs, and the person's relationship with food and body.
• ·Rapid weight change matters more than absolute weight — a body adapted to a higher set point can be in starvation physiology while still appearing 'normal.'
• ·The absence of an 'expected look' is one of the most common reasons these illnesses are missed.

Persistent restriction of energy intake relative to needs, leading to a significantly low body weight; an intense fear of weight gain (or behavior that interferes with weight gain); and a disturbance in the way body weight or shape is experienced, with weight unduly influencing self-worth or a lack of recognition of the seriousness of the low weight.

DSM-5 in brief. Two subtypes — restricting and binge-eating/purging. Amenorrhea was removed as a requirement. Severity is staged by BMI (mild, moderate, severe, extreme), though clinical risk often outpaces the number.

Recurrent episodes of binge eating paired with recurrent compensatory behaviors to prevent weight gain — self-induced vomiting, laxatives, diuretics, fasting, or driven exercise — on average at least weekly for three months, with self-evaluation overly tied to shape and weight. Weight is often normal or above, which is exactly why it hides.

Recurrent binge episodes — eating an unusually large amount in a discrete period with a sense of loss of control — at least weekly for three months, with marked distress, and without the regular compensatory behaviors that define bulimia. It is the most common eating disorder.

• ·Loss of control is the hallmark — the feeling of being unable to stop or to govern what and how much is eaten.
• ·Episodes often involve eating rapidly, past comfortable fullness, when not physically hungry, and alone out of embarrassment.
• ·Guilt, shame, and disgust typically follow, feeding a cycle of secrecy and further bingeing.

Pica is the persistent eating of non-nutritive, non-food substances — ice, clay, soil, chalk, paper, starch, hair, or paint — for at least a month, beyond what's appropriate for the person's developmental stage and outside culturally accepted practice. It is easy to overlook because patients rarely volunteer it; you have to ask.

When pica appears, check iron studies, consider lead and other toxic exposures, and place it in its developmental and life-stage context. Treat the underlying cause, not just the behavior.

Hyperphagia means pathologically excessive hunger — not overeating by choice, but a biological drive that overrides the normal sense of fullness. To understand it, start with how appetite is meant to work.

Appetite is the body's drive to eat, set by a constant conversation between the gut, fat tissue, and brain — a homeostatic system that balances hunger against fullness, layered with reward and emotion. Two hormones anchor that conversation:

When this system breaks — through leptin resistance (plenty of leptin, but the brain stops hearing it), hypothalamic injury, or a genetic syndrome — the brake fails. The person truly cannot feel full. Their hunger is real, relentless, and physiological; it is not a matter of discipline.

Prader-Willi is a genetic condition and the textbook cause of true, unrelenting hyperphagia. It arises from the loss of normally active paternal genes on chromosome 15 (region 15q11–q13). That stretch is imprinted — only the father's copy is switched on — so losing the paternal contribution silences it entirely.

Prader-Willi hunger is a genetic, hypothalamic failure of satiety. BED is a psychiatric disorder of loss-of-control eating in someone whose satiety physiology is intact. One is a broken 'off' switch; the other is a behavioral pattern.

Starvation, bingeing, and purging touch nearly every organ system. The pattern below guides both your exam and your monitoring.

Bradycardia simply means a slow heart rate. Normal resting rate in adults is 60–100 beats per minute; bradycardia is under 60.

In anorexia, the body deliberately slows its metabolism to conserve energy. The heart muscle itself becomes smaller and pumps more slowly, and resting rates can fall into the 40s or even 30s — often most pronounced overnight. It is an adaptation to starvation, not fitness.

Severe bradycardia can become life-threatening and is one of the clearest reasons a patient with anorexia may require hospitalization. Together with hypotension and orthostatic changes, it is a core trigger for inpatient medical stabilization and continuous monitoring.

One of the most misunderstood dangers in eating-disorder care: the body that has adapted to starvation cannot simply have its calories 'turned back on.' Reintroducing nutrition too quickly can trigger a cascade that is, paradoxically, most dangerous just as treatment begins.

• ·In starvation, the body burns fat and protein and quietly depletes intracellular phosphate, potassium, and magnesium — even while blood levels still look normal.
• ·Reintroduce carbohydrate, and insulin surges. Insulin drives phosphate, potassium, magnesium, and glucose into cells, and serum levels can crash.
• ·Hypophosphatemia is the hallmark — phosphate is essential for the energy (ATP) every cell, including heart and diaphragm, depends on.
• ·Carbohydrate metabolism also consumes thiamine, risking deficiency (and Wernicke's encephalopathy).

The resulting electrolyte and fluid shifts can cause cardiac arrhythmia and heart failure, respiratory failure, seizures, and death — within days of starting to feed.

Start low, go slow. Identify high-risk patients, correct electrolytes before and during refeeding, supplement phosphate, potassium, magnesium, and thiamine, and monitor labs closely. Refeeding is a medical procedure, not just a meal plan.