What is an Anorexic BMI?

Anorexia nervosa is a serious eating disorder that affects millions of people worldwide. One of the most common diagnostic criteria for anorexia is a low body mass index (BMI). However, what exactly is an anorexic BMI, and how is it calculated? In this article, we will discuss the definition of BMI, what qualifies as an anorexic BMI, and the dangers of having an extremely low BMI.

What is BMI?

Body mass index (BMI) is a measurement of body fat based on height and weight. BMI is a relatively simple and inexpensive way to screen for weight categories that may lead to health problems. BMI is calculated by dividing a person’s weight in kilograms by the square of their height in meters. For example, if a person weighs 60 kg and is 1.65 meters tall, their BMI would be calculated as follows:

BMI = 60 / (1.65 x 1.65) = 22.03

The World Health Organization (WHO) has established the following BMI ranges:

Underweight: less than 18.5 kg/m²
Normal weight: 18.5 to 24.9 kg/m²
Overweight: 25.0 to 29.9 kg/m²
Obese: 30.0 kg/m² or higher

You can also calculate BMI using NHS BMI Calculator.

What is an anorexic BMI?

An anorexic BMI is a BMI that falls below the normal weight range, specifically less than 18.5 kg/m². An anorexic BMI is one of the diagnostic criteria for anorexia nervosa, a type of eating disorder characterized by a distorted body image and an intense fear of gaining weight. People with anorexia may restrict their food intake, engage in excessive exercise, and engage in other unhealthy behaviors to maintain an extremely low body weight.

It’s important to note that not all people with anorexia have a low BMI. Some individuals with anorexia may have a normal BMI or even be overweight. This is because BMI is only one indicator of body weight, and does not take into account factors such as muscle mass, bone density, and body composition.

Why is an anorexic BMI dangerous?

Having an extremely low BMI can be dangerous for several reasons. First and foremost, it can lead to malnutrition and starvation. When the body doesn’t receive enough nutrients, it can’t function properly and this can lead to a host of health problems, including:

  • Weakness and fatigue
  • Dizziness and fainting
  • Constipation and digestive problems
  • Irregular or absent periods in women
  • Reduced bone density and increased risk of fractures
  • Slow or irregular heartbeat
  • Low blood pressure
  • Electrolyte imbalances
  • Weakened immune system
  • Cognitive impairment

In addition to physical health problems, having an anorexic BMI can also lead to psychological problems, such as depression, anxiety, and social isolation. People with anorexia may become obsessed with their weight and body shape and may experience feelings of shame, guilt, and worthlessness. They may also have difficulty maintaining relationships and engaging in social activities.

How is an anorexic BMI treated?

Treating anorexia nervosa can be challenging, as it is a complex disorder that involves both physical and psychological factors. The first step in treating anorexia is usually to restore the person’s weight to a healthy level. This may involve hospitalization or residential treatment, where the person can receive 24-hour medical care and support.

Once the person’s weight is stabilized, the focus shifts to addressing the psychological factors that contribute to their eating disorder. This may involve individual therapy, family therapy, and/or group therapy. Cognitive-behavioral therapy (CBT) is a common type of therapy used to treat anorexia, which helps the person change their thoughts and behaviors related to food and body image.

In addition to therapy, medication may be prescribed to help manage the physical and psychological symptoms of anorexia. Antidepressants, antipsychotics, and anti-anxiety medications may be used to treat depression, anxiety, and other psychological symptoms. Nutritional supplements and vitamins may also be recommended to help the person regain their physical health.


Preventing anorexia nervosa is not always possible, as it is a complex disorder that can develop for a variety of reasons. However, some steps can be taken to reduce the risk of developing an eating disorder. These include:

  1. Promoting a healthy body image and self-esteem
  2. Encouraging healthy eating habits and regular exercise
  3. Educating young people about the dangers of fad diets and extreme weight loss measures
  4. Encouraging open communication about feelings and emotions
  5. Seeking professional help if you or a loved one is struggling with an eating disorder
  6. Conclusion

An anorexic BMI is a BMI that falls below the normal weight range, specifically less than 18.5 kg/m². Having an anorexic BMI can be dangerous, leading to malnutrition, physical and psychological health problems, and social isolation. Treating anorexia involves restoring the person’s weight to a healthy level and addressing the psychological factors that contribute to their eating disorder. Prevention involves promoting a healthy body image, encouraging healthy habits, and seeking professional help if needed.

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