Anorexia nervosa produces symptoms across three categories: physical changes from malnutrition, psychological distortions around body image and food, and behavioral patterns that become increasingly rigid over time. Many of these symptoms overlap and reinforce each other, making the condition progressively harder to reverse the longer it continues. Anorexia carries the highest mortality rate of any eating disorder, with a death rate roughly five times that of the general population.
The Core Psychological Symptoms
The defining psychological feature of anorexia is a persistent, intense fear of gaining weight or becoming fat, even when a person is clearly underweight. This isn’t ordinary body dissatisfaction. People with anorexia often hold convictions about being overweight that can reach delusional intensity, persisting despite substantial evidence to the contrary. They tend to focus on specific body areas they perceive as “fat,” particularly the abdomen, hips, and face.
Research on visual processing shows that people with anorexia exhibit hypervigilant attention to details of their own appearance, with a tendency to zero in on perceived flaws while missing the bigger picture. This pattern of over-focusing on specific body parts while underprocessing their overall appearance helps explain why someone who is severely underweight can genuinely believe they look overweight. Importantly, this perceptual distortion tends to improve with weight restoration, suggesting it is a symptom of the illness rather than a fixed personality trait.
Low self-esteem is deeply intertwined with these body image symptoms. A person’s sense of self-worth becomes almost entirely tied to their weight and shape, so any perceived change in their body triggers anxiety that can feel unbearable.
Behavioral Warning Signs
The earliest and most common behavioral change is dieting. In adolescents, dieting typically begins around age 14, followed by increasingly rigid food restriction, and formal diagnosis usually doesn’t happen until slightly past age 15. That gap of a year to a year and a half between the first behavioral changes and diagnosis is significant, because it represents a window where early intervention could make a real difference.
As the disorder progresses, eating rituals become elaborate and highly specific. These include cutting food into tiny geometric shapes, separating food groups on the plate, chewing each bite a set number of times, diluting food with water to make it appear like more, eating extremely slowly with long pauses between bites, counting morsels, and hiding or discarding food. These rituals serve a dual purpose: they slow down eating and create an illusion of control over food intake.
Other behavioral patterns to watch for include excessive exercise (which often develops after restriction is already established), wearing layered or baggy clothing to hide weight loss, withdrawing from meals with family or friends, and cooking elaborate meals for others while refusing to eat. People with the binge-eating/purging subtype also engage in episodes of eating followed by self-induced vomiting or laxative misuse, and they tend to show higher levels of distress around eating and greater preoccupation with shape and weight compared to those who only restrict.
Physical Signs of Malnutrition
The body responds to prolonged starvation in ways that become visible over time. One of the more distinctive signs is the growth of lanugo, a fine, soft, colorless hair that appears on the face, arms, and torso. The body produces this hair as an insulation response when it can no longer regulate temperature normally due to lost body fat. Feeling cold all the time, even in warm environments, is a related and very common complaint.
Other visible physical changes include dry, yellowish skin (from elevated levels of a pigment found in vegetables, which the body can no longer metabolize efficiently), brittle nails, thinning hair on the scalp, and a gaunt or hollow appearance in the face. Hands and feet may appear bluish or purple from poor circulation.
Cardiovascular Effects
The heart is one of the organs most affected by anorexia. Bradycardia, a resting heart rate below 60 beats per minute, is the most common heart rhythm abnormality in both adolescents and adults with the condition. In clinical studies, about 36% of eating disorder patients show this slowed heart rate, with some individuals dropping as low as the 40s. Blood pressure also falls, sometimes to levels like 99/60 mmHg. These changes reflect the body’s attempt to conserve energy by slowing everything down, but they can become life-threatening if not recognized. The good news is that heart rate and blood pressure typically improve with even modest weight gain.
Digestive Complications
Constipation is the single most common gastrointestinal symptom in anorexia. Malnutrition causes the smooth muscle lining the digestive tract to weaken and atrophy, which slows the movement of food through the gut. Even after someone begins eating again, the sensation of constipation can persist because of damage to the pelvic floor muscles from prolonged malnutrition.
Gastroparesis, where the stomach empties much more slowly than normal, is also common. It causes bloating, nausea, a feeling of fullness after eating very little, and abdominal pain. This creates a vicious cycle: the physical discomfort of eating reinforces the desire to avoid food. Gastroparesis tends to worsen with longer duration and greater severity of malnutrition, but it generally improves with consistent nutritional rehabilitation.
Hormonal and Reproductive Changes
Anorexia disrupts the hormonal signaling chain that controls reproduction. As body fat drops, leptin levels plummet. In adolescent girls with anorexia, overnight leptin levels run about 71% lower than in healthy peers. Since leptin is one of the key signals that tells the brain it’s safe to reproduce, the brain essentially shuts down the reproductive system. Periods stop (a condition called amenorrhea), and estrogen and testosterone levels fall significantly.
The reproductive system is surprisingly responsive to recovery. In one study of 100 adolescent girls with anorexia, 86% of those who reached 90% of their ideal body weight had their period return within six months. However, about 15% of women continue to experience amenorrhea even after reaching a normal weight, and there is no exact body weight or body fat percentage that guarantees periods will resume. Elevated cortisol, the body’s stress hormone, is another hallmark of active anorexia and contributes to both the anxiety and depression that commonly accompany the disorder.
Bone Density Loss
One of the most serious and potentially permanent consequences of anorexia is damage to the skeleton. In adults with the condition, 92% have some degree of bone thinning, and 38% meet the threshold for osteoporosis at one or more skeletal sites. Adolescents are affected too: up to 50% of girls with anorexia show compromised bone density, and boys fare even worse, with 70% showing measurable bone loss.
This matters because the teenage years and early twenties are when the skeleton is supposed to be building to its peak strength. Disrupting that process has consequences that persist for life. Research shows that anorexia’s effects on bone mass remain detectable even after full recovery, making this one of the few complications that may not fully reverse with treatment.
Atypical Anorexia: Symptoms Without Low Weight
A person can experience nearly all of the psychological and behavioral symptoms of anorexia while still being at a normal or higher body weight. This is classified as atypical anorexia nervosa, and it is not a milder version of the illness. People with atypical anorexia actually report higher levels of preoccupation with their weight and shape than those with the classic form. No significant differences exist between the two groups in overall eating disorder severity, harmful eating behaviors, rates of other psychiatric conditions, or levels of perfectionism.
The key distinction is that those with classic anorexia tend to score higher on food-related fears, including anxiety about eating in social settings and obsessive-compulsive symptoms. But in terms of the damage the illness does to a person’s life and functioning, the two presentations are equally impairing. This means that someone who has lost a significant amount of weight rapidly, or who shows the psychological and behavioral symptoms described above, warrants concern regardless of what the scale says.