BMI is an indicator of how healthy a person's weight is. It is a chart that will help you to calculate a person's BMI and to use this to determine whether they are a healthy weight, underweight, overweight, obese, or extremely obese (see Figure 4.4., below). Being overweight is a risk factor for developing Type 2 diabetes. However, simply weighing someone may not accurately determine if they are overweight.

• Explain how it is possible for one person who weighs 80 kg to be obese, and another person who also weighs 80 kg to be a healthy weight.
• The key point is their difference in height. One may be taller and assessed as an average weight for their height, whereas the other is assessed as obese because they are much shorter. The relationship between weight and height is determined by calculating the person's Body Mass Index (BMI).

Your BMI is defined by your weight in kilograms divided by your height in metres square

NB: The chart does not apply to athletes, children, pregnant or lactating women.

Mr Elyas is 1.65 m tall and weighs 60 kg. Mr Asrat is also 1.65 m tall but weighs 80 kg. Use Figure 4.4 to estimate their BMI. What does the BMI of each man indicate about the risk of developing Type 2 diabetes?

• Mr Elyas's BMI is 22, so he has a healthy weight for his height, which does not increase his risk of developing Type 2 diabetes. However, Mr Asrat's BMI is 29, which means he is overweight and therefore at increased risk of becoming diabetic.