WebMD News Archive
Can you be obese and have a clean bill of health?
The medical community has begun to acknowledge that some people classed as ‘obese’ may not be as at risk of serious health problems as doctors previously thought. This has led to a new medical categorisation - ‘metabolically healthy obesity’.
BMJ Group News
What is obesity?
People are classed as ‘obese’ when their body mass index (BMI) is greater than 30. Your BMI number is your weight divided by the square of your height. So, for example, a man who is 5 feet ten inches (1.78 metres) tall and weighs 14 stone (89 kilograms) has a BMI of 28. If you want to work out your BMI and these kinds of sums aren’t your strong point, BMI calculators are easy to find online. Doctors use BMI to measure whether you’re a ‘healthy’ weight. The reason doctors think that having a BMI of over 30 is unhealthy is because people in this weight range are usually more at risk from serious conditions like heart disease, some cancers, and diabetes.
People who are obese are encouraged by their doctors to lose weight. If you are obese your doctor will usually suggest a diet and an exercise regime. They may also do tests to see if an underlying illness is making you unable to lose weight.
In some cases, a doctor may prescribe an anti-obesity medication, called orlistat. But if none of these treatments works and your doctor thinks your health is seriously in danger, they may recommend you have weight-loss surgery, called bariatric surgery.
What is metabolically healthy obesity?
But what is metabolically healthy obesity, and how are doctors able to recognise when someone has it? A new medical journal article examines the issues. Because ‘metabolically healthy obesity’ is a new category of obesity, doctors haven’t agreed on a strict definition of it yet. But the thinking is that people who are obese, but metabolically healthy, don’t seem to be as at risk from health complications as other people in their weight range.
Doctors think it is probably down to a combination of factors. For instance, obese people are normally ‘ insulin resistant’. This means that their cells don’t respond properly to insulin, the hormone that regulates blood sugar and that has effects on fat metabolism. But some small studies have surprised doctors by reporting that this might not apply to all obese people. The way that fat is distributed around the body - for instance, if the fat isn’t mostly centred around the waist - may also have an effect.
The authors of the journal article suggest that doctors might be able to diagnose this new kind of obesity in people with a BMI of over 30 with:
- normal insulin resistance and normal blood pressure
- no problems breathing, and
- a waist circumference of less than 102 centimetres for men and 88 centimetres for women.
The authors argue that the health of obese people should be defined by how fit they are, not how fat they are. So they suggest that treadmill exercises are a useful way for doctors to measure their patients’ fitness levels, instead of focusing on their weight.