What BMI is Considered Morbidly Obese?

Body Mass Index (BMI) is a widely used tool for assessing the weight status of an individual. It is a measure of body fat based on a person’s height and weight. BMI is used to screen for overweight and obesity, which is a growing concern globally. The World Health Organization (WHO) defines obesity as having a BMI greater than or equal to 30, and morbid obesity is having a BMI greater than or equal to 40. In this article, we will discuss in detail what BMI is and what BMI is considered morbidly obese.

What is BMI?

BMI is a measure of body fat based on a person’s weight and height. It is calculated by dividing a person’s weight in kilograms by the square of their height in meters. The formula for calculating BMI is:

BMI = weight (kg) / height (m)²

For example, if a person weighs 80 kilograms and is 1.8 meters tall, their BMI would be calculated as follows:

BMI = 80 / (1.8)² = 24.7

The resulting number is then used to determine the weight status of the individual. BMI is a simple, non-invasive, and inexpensive tool for assessing weight status. However, it is not always an accurate measure of body fat, especially in athletes and bodybuilders. You can use NHS BMI calculator for calculating BMI.

BMI and Weight Status:

BMI is used to classify individuals into different weight status categories. The following table shows the weight status categories based on BMI:

BMI Category Weight Status

  • <18.5 Underweight
  • 18.5-24.9 Normal weight
  • 25.0-29.9 Overweight
  • 30.0-34.9 Obesity (Class I)
  • 35.0-39.9 Obesity (Class II)
  • ≥40.0 Morbid Obesity (Class III)

The weight status categories based on BMI are only a guide and should be used in conjunction with other measures such as waist circumference, blood pressure, and cholesterol levels to determine an individual’s overall health status. For example, an individual with a BMI of 30 who has a large waist circumference and high blood pressure may have a higher risk of developing health problems than an individual with the same BMI but a smaller waist circumference and normal blood pressure.

What is Morbid Obesity?

Morbid obesity is a condition in which an individual’s weight poses a significant risk to their health. It is defined as having a BMI greater than or equal to 40. Morbid obesity is associated with an increased risk of developing various health problems such as heart disease, stroke, type 2 diabetes, high blood pressure, sleep apnea, and certain types of cancer.

Morbid obesity is also associated with a reduced quality of life, social stigma, and discrimination. It can limit an individual’s ability to perform daily activities and lead to psychological problems such as depression and anxiety. Morbid obesity is a serious health condition that requires medical attention and long-term management.

Causes of Morbid Obesity:

Morbid obesity is a complex condition that is caused by a combination of genetic, environmental, and behavioral factors. Some of the common causes of morbid obesity include:

Genetic Factors: Some people may be predisposed to obesity due to their genetic makeup. Studies have shown that certain genes can affect a person’s appetite, metabolism, and fat storage.

Environmental Factors: The environment in which a person lives can also contribute to their risk of obesity. Factors such as access to unhealthy food, a sedentary lifestyle, and lack of physical activity can all contribute to weight gain. Who lead a sedentary lifestyle with little to no physical activity is also at a higher risk of developing obesity.

Poor dietary habits often involve the consumption of foods that are high in calories but low in nutritional value, such as fast food, processed snacks, sugary drinks, and desserts. These foods are often convenient, inexpensive, and readily available, which can make it difficult for individuals to make healthier choices.

In contrast, a healthy diet that promotes weight loss typically involves consuming nutrient-dense foods such as fruits, vegetables, whole grains, lean proteins, and healthy fats. This type of diet can help individuals feel full and satisfied while also providing the necessary nutrients for optimal health.

A lack of physical activity is also a significant contributing factor to obesity. Inactivity can cause a decrease in muscle mass and a slower metabolism, which can lead to weight gain. A sedentary lifestyle can also increase the risk of developing health problems such as heart disease, diabetes, and certain types of cancer.

Regular physical activity, on the other hand, can help burn calories and build muscle, which can increase metabolism and promote weight loss. Exercise can also provide numerous health benefits, such as improved cardiovascular health, reduced stress and anxiety, and increased energy levels.


In summary, poor dietary habits and a lack of physical activity are two of the most common behavioral factors that contribute to morbid obesity. Making healthy food choices and incorporating regular physical activity into one’s daily routine can help prevent and treat obesity, as well as promote overall health and well-being.

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