Question: What is obesity?

Keith Brain answered on 24 Jun 2010:

Obesity is basically being too heavy for what most people consider to be healthy.

There is technical definition, which is based on something called the “Body Mass Index” (BMI). You can calculate your own BMI by taking your weight in kg, and dividing by the square of your height (measured in meters). In the UK, the standard definition of obesity is a BMI of over 30 for adults. For children, its a more complex calculation, and usually charts are used to check it – a bit like the height and weight charts in the back of the Health Record books some you might still have.

So, for someone I know (cough), they have:
Weight = 72 kg
Height = 1.87 m

So, their BMI is 72/(1.87*1.87)=72/1.87/1.87= 20.6
So, they are not obese, as their BMI is less than 30.

Their wife thinks that they are too thin, but I disagree.

There are other ways of measuring obesity, like measuring the thickness of a fold of skin over your abdomen (tummy). This is a measure of how much fat you have under the skin. However, this can be tricky to measure reliably.

Why worry about obesity? Because it increases the risk of getting some diseases, like having heart attacks (very nasty) or diabetes. Diabetes is a problem because, if not properly controlled, it increases the risk of heart attacks, stokes, eye problems, kidney problems, and lots of other bits and pieces.

So, a healthy diet and regular exercise are important, in part to control weight and help reduce the risk of many important diseases (oh dear, that was a long sermon …!)