Obesity is defined by medical professionals as a complex and progressive disease where excess or abnormal body fat causes and increases the risk of long-term health complications.

The most common way to classify obesity is by using the Body Mass Index (BMI) - a measure calculated by dividing weight in kilograms by the square of height in meters. In most people, a BMI of 25 kg/m² or more represents an increased risk of obesity and overweight symptoms and requires additional evaluation. While BMI does not qualify an obesity diagnosis, a BMI of 30 kg/m2 or more is associated with increased cardiovascular risk and mortality, and anyone with a BMI of 30 or above should consult their doctor for support.

BMI is an objective way to classify underweight, normal weight, overweight, and obesity in adults. Within the official obesity definition, there are different classifications of the disease.

These classifications are a standardised measurement and form part of an internationally recognised obesity definition. 

In addition to a BMI of 25 kg/m² or more, there are other symptoms of obesity that can impact your day-to-day life.  Obesity symptoms may include:

• Difficulty doing physical activity like climbing stairs
• Breathlessness
• Increased sweating
• Snoring
• Feeling tired regularly
• Joint pain
• Back pain
• Low confidence and self-esteem
• Feeling isolated
• Depression, anxiety, and mood disorders

If you're experiencing any of these symptoms, it's a good idea to talk to your doctor.

Losing weight and keeping it off is often seen as a question of “energy in and energy out” – how much you eat and how much you move. But science has proven that there are many causes of obesity, some of which are beyond your awareness or control.

The causes of obesity are complicated and vary from person to person. These include:

• Genetics. Tiny genetic variations can make you more likely to carry weight and develop obesity.
• Hormones. The balance of hormones in your body can affect your appetite and food choices, as well as how much energy you use.
• Stress. High stress levels can make you overeat and gain weight.
• Sleep. How much and how well you sleep can affect your hormones, which can make you eat more food.
• Medications. Some medicines can increase your appetite or affect your metabolism so that you gain weight.
• Environment and socioeconomic status. Where you live and your access to different kinds of food is related to developing obesity.

There are so many reasons for obesity. And once a person has developed obesity, it's not easy to manage weight and keep it off. Because of this, it can be hard to find the right way to treat or manage obesity.
 

An obesity diagnosis may be an important step in treating and managing obesity the condition.

Diagnosing obesity usually involves an assessment of lifestyle, medical and family history, a physical examination and/or laboratory tests.

To assess lifestyle, medical and family history, a healthcare provider may ask questions related to your:

• Ethnicity
• Family history
• Diet
• Physical activity and exercise habits
• Eating disorders
• Depression and other mood disorders
• Genetics
• Medications
• Chronic stress
• Smoking habits

A physical exam

A physical examination may also be necessary to support a formal diagnosis of obesity. Guidelines recommend doctors carry out an Edmonton Obesity Staging System (EOSS), which is a measure of the mental, metabolic and physical impact of obesity. This can then help your doctor find the right treatment plan for you.  

This may include:

• Measuring weight, height, and waist circumference
• Measuring blood pressure
• Assessing if you have obesity-related complications (for example, diabetes, hypertension, mental health disorders, osteoarthritis, respiratory disease, and others)
• Checking for obesity-related skin problems such as acanthosis nigricans (dry, dark patches of skin that can be a sign of insulin resistance)

Laboratory tests

Lastly, laboratory tests may be administered to identify the underlying signs and symptoms of obesity. Your doctor will select what laboratory tests to run depending on your case and assessment needs. 

Laboratory tests may be used to assess:

• Fasting blood glucose (to measure your sugar levels when they are at their lowest)
• Cholesterol test (including total, high-density lipoprotein and low-density lipoprotein cholesterol, triglycerides)
• Uric acid (a normal waste product that passes through your kidneys and leaves your body in urine)
• Thyroid function and endocrine evaluation (to assess your hormone levels)
• Liver function
• Liver investigation (including ultrasound or biopsy)
• Non-alcoholic fatty liver disease (NAFLD) or other liver pathology
• Cardiovascular assessment
• Sleep laboratory investigation for sleep apnoea (when your breathing stops and starts in your sleep)

Discuss with your doctor, the steps you are wiling to take to better manage your obesity, any challenges you may have faced in the past in this regards, potential benefits of maintaining a healthy weight and any possible complications that can arise in the future.

These classifications are a standardised measurement and form part of an internationally recognised obesity definition. 
 

There are lots of ways to treat obesity and manage weight. Each obesity treatment works in a different way and is typically recommended to be used alongside diet and exercise. With the help of healthcare professionals, you can find the right obesity care and create an obesity care plan specifically for you. 

Obesity is a complex disease with many causes. Partner with your doctor to guide you through an obesity care plan, created just for you. Here's an overview of 5 scientifically-proven obesity treatment options* that can be a part of it.

Option #1: Modification to your diet

Forget the miracle diet as an obesity treatment. When it comes to managing weight and obesity, there are a number of routine changes to consider.

Your doctor will take your eating habits and physical activity into consideration when creating your obesity care plan. Some of the things you can look at together include:

• Time. Is there a specific time of day when you're more likely to eat higher calorie foods?
• Place. Where do you normally eat? 
• Emotions. Do you eat higher calorie foods when you feel a certain way? For example, when you feel tired, stressed, or sad?
• Feeling full. How do you experience the feeling of fullness after a meal?

You can also discuss reduced-calorie diets with your healthcare provider. When prescribed by a healthcare professional, this is often referred to as moderate (1300-1500 kcal/day), low-calorie (900-1300 kcal/day), or very low-calorie (less than 900 kcal/day) diets. As a calorie restricted diet can impact other parts of your mental and physical health, it is important that you work with your doctor to find the right support team for you.

Option #2: Increasing your daily movement and physical activity

Moving more and using more energy is another lifestyle modification that can help with weight management. Whether or not it results in a reduction in weight, physical activity can also improve many aspects of your life. Regular physical activity can result in health benefits for people in all BMI categories, such as improving cardiometabolic risk factors.

Start by adding a little extra movement into your everyday life. If you sit a lot during the day, standing up and moving around for a few minutes every hour can make a difference. So can walking to the shops or taking the stairs, if possible. Even doing small things can mean a lot. The goal is to have 150 minutes of physical activity a week. You can build up towards this goal by gradually adding new activities and routines into your obesity care plan.

Discussing these modifications to your daily routine with your healthcare provider can help you understand what is making you gain weight or preventing you from losing weight and help your doctor create a more sustainable weight management plan.

Option #3: Behavioural therapy

This therapy uses principles from behavioural sciences and cognitive therapies to identify and replace behaviours with healthy alternatives. Behavioural therapy are programmes that help patients reach their behavioural or health goals.

Behavioural therapists work with the psychological aspects of weight management. They can help you identify patterns in your thoughts, emotions, and behaviour that make you eat more and gain weight. Eating large portions, snacking frequently, and/or eating or drinking when you're not hungry are just some of the patterns you may have around food. The focus of behavioural therapy is to empower people living with obesity to make sustainable changes that improve their health, as well as promote their self-esteem and confidence. Doing this can help you manage your weight in the long term, improve your health status, and quality of life.
 

Option #4: Obesity medications

There are different obesity medications available and they work in different ways. Some obesity medications help regulate your appetite and food cravings, which may make it easier to change your lifestyle.

Obesity medications can also help prevent weight regain. They do this by managing the way your body responds when you manage weight, such as the constant feeling of hunger.
 

Option #5: Bariatric surgery

Gastric bypass and other weight-loss surgeries — known collectively as bariatric surgery — involve making changes to your digestive system to help you lose weight. Bariatric surgery is an obesity treatment that can lower your appetite and the amount of food you can comfortably eat in one sitting. They've been shown to change the body's metabolism and hormones, both of which play a major role in how your weight is regulated. For example, the hormonal changes from bariatric surgery work to prevent weight regain.