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Morbid obesity: How it's classified and treatment options

We've put together everything you need to know about morbid obesity.

Morbid Obesity: How It's Classified and Treatment Options | Juniper

Have you ever wondered how carrying excess weight can affect your overall well-being? If you're on a personal weight loss journey and searching for practical strategies and insights to shed excess weight and maintain a healthy body weight, you're not alone.

Understanding where you fall in the overweight range can be a common curiosity for many people on their weight management journey.

That's why we've put together everything you need to know about morbid obesity, from what might cause it to practical strategies to help you achieve and sustain a healthy weight. Whether you're taking the first steps towards your weight loss goals or looking for fresh perspectives to reignite your journey, we've got you covered.

What is morbid obesity?

Class III obesity, a.k.a morbid obesity, is a complex and long-lasting health condition. It occurs when a person's body mass index (BMI) is categorised as high and is characterised by excessive body fat.

It's important to note that those with severe obesity are at significantly higher risk of developing serious medical issues. Plus, it can profoundly impact a person's overall health and quality of life.

Severe obesity can lead to various health problems, such as type 2 diabetes, heart disease, high blood pressure, sleep apnoea, and more [1]. It may seem challenging for those with morbid obesity to lose weight, but it is possible.

If you think you may fall into the morbid obesity category, it's important to seek help from a trusted healthcare professional who will guide you through the weight loss journey.

What is classed as morbidly obese in the UK?

In the United Kingdom, morbid obesity is defined as having a body mass index (BMI) of 40 or higher [2]. This BMI value is an indicator of a person's weight relative to their height and serves as a common metric for assessing obesity, but it isn't the only way to determine obesity.

In some cases, if an individual has a BMI of 35 or higher and is experiencing health issues related to obesity, they may also be classified as morbidly obese. However, if you have a South Asian, Chinese, another Asian, Middle Eastern, Black African or African-Caribbean family background, you can have a lower BMI but still be categorised as having class III obesity [3].

BMI, or body mass index, is calculated by dividing a person's weight in kilograms by the square of their height in metres. It's widely used to evaluate whether someone falls into the overweight or obese category based on their numerical BMI score.

However, it's worth noting that healthcare professionals may use alternative methods to assess obesity and its associated health risks comprehensively. One method might be measuring waist circumference.

Addressing morbid obesity may involve comprehensive medical and lifestyle interventions tailored to an individual's specific needs and circumstances.

What is the difference between morbidly obese and obese?

Obesity and morbid obesity are different levels of a health condition related to having excess body fat. Let's take a look.


Obesity is a condition where a person has more body fat than what's considered healthy. This extra fat can increase the chances of various health issues, including heart disease, high blood pressure, type 2 diabetes, sleep problems, certain cancers, and mental health concerns.

If someone's BMI is greater than 30, they are considered obese. Obesity is further divided into 3 classes [4]:

  1. Class 1 obesity: BMI of 30-34.9
  2. Class 2 obesity: BMI of 35-39.9
  3. Class 3 obesity: BMI of 40 or higher, also known as morbid obesity

Morbid obesity

Morbid obesity, sometimes called clinically severe obesity, is a more severe form of obesity. It's usually defined as being over 100 pounds overweight or having a BMI of 40 or higher [5].

Super morbid obesity

Occasionally, you might hear the term "super morbidly obese" used for individuals with a BMI of 50 or higher. This category represents an even more severe form of obesity and comes with a higher risk of health complications.

What causes morbid obesity?

Morbid obesity is a complex and multifaceted health condition influenced by a combination of factors such as genetic and environmental factors.

Here's an overview of some of the most common factors contributing to its development:


Did you know genetics can play a substantial role in obesity? In some cases, a specific genetic variant may lead to inherited obesity within families. In fact, our genes account for 40-70% of the likelihood of having obesity [6].

Environmental and social factors

Sometimes, obesity can result from unhealthy dietary habits, a sedentary lifestyle, and a lack of physical activity. But it can also be influenced by socioeconomic status, access to nutritious foods, and cultural influences.

Medical conditions and medications

Certain medical conditions like Prader-Willi syndrome [7], Cushing syndrome [8], or arthritis can lead to reduced physical activity and weight gain.

Plus, specific medications, such as antidepressants and steroids [9], may cause weight gain as a side effect.

Psychological factors

Emotional factors like stress, anxiety, and depression can influence overeating and contribute to weight gain.

It's important to remember that morbid obesity is a complex condition that may result from these or a combination of these factors. It is not solely due to a lack of self-control or willpower. Even things such as our sleep quality can influence how our bodies hold weight.

Treating morbid obesity involves adopting a holistic approach, which includes healthy dietary choices, regular physical activity, and behaviour modifications to manage the condition and achieve weight loss effectively.

How is morbid obesity diagnosed?

Diagnosing morbid obesity involves a few key steps that healthcare providers use to understand a person's health.

  1. Body mass index (BMI): To begin, they measure something called body mass index or BMI, which calculates your weight in relation to your height. If your BMI reaches 40 or higher, it's classified as morbid obesity.
  2. Additional assessments: Healthcare providers don't rely solely on BMI. They also consider other factors, like waist circumference, to get a more comprehensive picture of your condition.
  3. Checking for health conditions: Beyond measuring your weight, they also look for health issues that are often associated with obesity. These can include type 2 diabetes, heart disease, high blood pressure, sleep apnoea, and more.

Complications of morbid obesity

Morbid obesity is a complex and enduring health condition that can lead to several serious health challenges. Here's a look at some of the complications associated with morbid obesity [10]:

  • Heart disease and strokes: Morbid obesity increases the risk of conditions like high blood pressure and abnormal cholesterol levels, which can contribute to heart and cardiovascular disease and strokes
  • Type 2 diabetes: Obesity can affect how the body uses insulin to control blood sugar levels, increasing the risk of developing type 2 diabetes
  • Certain cancers: Morbid obesity may raise the risk of various cancers, including uterine, cervical, breast, colon cancer and more
  • Digestive issues: Morbid obesity can lead to problems like heartburn, gallbladder disease, and liver concerns
  • Sleep apnoea: Obesity is a major factor in sleep apnoea, a condition characterised by breathing interruptions during sleep
  • Gastrointestinal and hepatobiliary complications: These can include issues like GERD, gallstones, and fatty liver disease
  • Pulmonary complications: Chronic hypoxia and hypercapnia in obesity can increase the risk of pulmonary hypertension, right-sided heart failure, and cor pulmonale
  • Pregnancy-related complications: For pregnant individuals, obesity can heighten the risk of conditions like gestational diabetes and preeclampsia
  • Emotional and social challenges: Morbid obesity can be accompanied by low self-esteem, isolation, and other emotional and social difficulties

These complications can significantly affect a person's overall well-being and quality of life, including life expectancy rates.

That's why it's essential to talk to a healthcare professional to create a comprehensive treatment plan that not only helps you lose weight but also addresses the physical and emotional aspects of this condition if you think you might be morbidly obese.

Treating morbid obesity

One key way of managing morbid obesity involves making healthy lifestyle adjustments. This might look like adopting a reduced-calorie, well-balanced diet and incorporating regular physical activity into your routine.

Activities like brisk walking, jogging, swimming, or playing tennis for 150-300 minutes per week can be beneficial in managing this condition.

You may also need to seek support in addressing the behavioural and psychological facets of morbid obesity. In some cases, weight-loss medications prescribed by healthcare providers, such as bupropion-naltrexone, liraglutide, orlistat, or phentermine-topiramate, may be integrated into the treatment plan.

Lastly, for individuals with morbid obesity, bariatric surgery is a common option. This surgical procedure involves reducing the stomach's size, thus limiting food intake and facilitating substantial weight loss. It is typically recommended for those facing challenges in managing obesity-related health conditions through lifestyle changes and medications.

Looking for a holistic and science-backed approach to weight loss? Juniper’s Weight Reset Programme includes clinically proven weight loss medication with tailored support from a team of professionals, including dietitians and nutritionists, to help you lose weight and keep it off.