Obesity and Overweight in Adults
If you are obese or overweight, you have an increased risk of developing various health problems. Even a modest amount of weight loss can help to reduce your increased health risks. The best chance of losing weight, and keeping the weight off, is to be committed to a change in lifestyle. This includes eating a healthy diet and doing some regular physical activity.
Are you obese or overweight?
If you are obese or overweight, this means that you are carrying excess body fat. Being overweight or obese is not just about how you look. Over time, it means that you have an increased risk of developing various health problems. As an adult, you can find out whether you are overweight or obese and whether your health may be at risk, by calculating your body mass index (BMI) and measuring your waist circumference.
Body mass index – BMI
People are different heights and builds, so just weighing yourself cannot be used to decide if your weight is healthy. BMI is used by healthcare professionals to assess if someone’s weight is putting their health at risk. It is a measure of your weight related to your height. To calculate your BMI, you divide your weight (in kilograms) by the square of your height (in meters). So, for example, if you weigh 70 kg and are 1.75 meters tall, your BMI is 70/(1.75 x 1.75), which makes 22.9.The table below shows how to interpret your BMI. In general, the more your BMI is over 25, the more overweight or obese you are and the greater the risk to your health.
| BMI | Classed As | Health Risk |
| Less than 18.5 | Underweight | Some health risk |
| 18.5 to 24.9 | Ideal | Normal |
| 25 to 29.9 | Overweight | Moderate health risk |
| 30 to 39.9 | Obese | High health risk |
| 40 and over | Very obese | Very high health risk |
On the whole, BMI is a good estimate of how much of your body is made up of fat. However, BMI may be less accurate in very muscular people. This is because muscle weighs heavier than fat. So, someone who is very muscular may have a relatively high BMI due to the weight of their muscle bulk but actually have a proportionally low and healthy amount of body fat.
Waist circumference
If you are overweight, measuring your waist circumference can also give some information about your risk of developing health problems (particularly coronary heart disease and type 2 diabetes). If two overweight or obese people have the same BMI, the person with a bigger waist circumference will be at a greater risk of developing health problems due to their weight. This is because it is not just whether you are carrying excess fat but where you are carrying it. The risks to your health are greater if you mainly carry a lot of extra fat around your waist (‘apple-shaped’), rather than mainly on your hips and thighs (‘pear-shaped’). The easiest way to measure your waist circumference is to place the tape measure around your waist at belly button level.
As a rule for a man:If you have a waist measurement of 90 cm or above, the risk to your health is increased.If you have a waist measurement of 102 cm or above, the risk is even higher.
As a rule for a woman:If you have a waist measurement of 80 cm or above, the risk to your health is increased.If you have a waist measurement of 88 cm or above, the risk is even higher.
Note: for people from Asian backgrounds, the increased health risks may start at a lower waist circumference.