If you’re obese, it means you’re very overweight which can increase your health risks.

By Wallace Health I Medically reviewed by Adrian Roberts.
Page last reviewed: October 2018 I Next review due: October 2021

What is obesity?

The definition of obesity for adults is a body mass index (BMI) of over 30. You can work out your BMI by dividing your weight in kilograms by the square of your height in metres. Or you can use an online calculator.

Obesity usually means you’re eating and drinking more calories than your body can use. The extra calories are stored as fat.

Around one in four adults (and one in five children) in the UK is obese.

Obesity isn’t a disease. However, the effects of obesity can be severe as you’re more likely to have serious health problems, like diabetes, gout, cancer and heart disease. Obesity can also increase your risk of developing arthritis. If your BMI’s over 40 it’s known as morbidly obese because it can shorten your life.

You can reduce the risks by losing weight.

How to tell if you have obesity symptoms

Obesity symptoms include breathlessness and being very overweight with a lot of body fat.

If your BMI is between 18.5 and 24.9 then it’s healthy.

If it’s over 35, and if your waist measures more than 94cm, it can mean you’re obese.

Some people have a high BMI but aren’t obese. That’s because they have more muscle or don’t have much fat.

If you’re worried about your weight, ask your GP for advice.

Talk to your doctor if you’re concerned about symptoms

You can book an appointment with a Spire private GP today.

Book an appointment

Diagnosis and tests for obesity

Your GP will be able to explain what’s a healthy weight and measurement for you. They may calculate your BMI and take your waist measurement.

They may also carry out some tests to check for health conditions including Type 2 diabetes and an underactive thyroid.

Causes of obesity

Causes of obesity include eating and drinking too many calories without exercising enough to burn them off. It’s more likely if your diet is high in fat and sugar, such as:

  • Takeaways or ready-made meals
  • Alcohol or high-sugar drinks

If you have a healthy lifestyle but still find it difficult to lose weight, it might be caused by a medical condition, (eg Cushing’s syndrome or an underactive thyroid).

Some prescription medications, such as steroids, can also make it easier to gain weight.

There may also be a genetic link.

Common treatments for obesity

Your GP will suggest you make some lifestyle changes, such as eating healthy foods and taking more exercise. They may refer you to a dietitian to help you plan your meals or suggest you try a local weight loss class. Joining an exercise class or gym can help you stay motivated.

If it’s very challenging for you to lose weight, your GP may prescribe medication to help.

If you’re very obese, they may suggest you have weight loss (bariatric) surgery such as a gastric bypass or gastric sleeve.