4 Prevention is better than cure

4.4 Obesity and cardiovascular diseases

Obesity and being overweight are well-known as risk factors for cardiovascular diseases. Carrying excess body fat predisposes individuals to developing elevated blood cholesterol and diabetes. You will begin to appreciate that many of the modifiable risk factors for cardiovascular diseases are interlinked. This means that influencing one, such as reducing the amount of stored lipids in the body, may have a positive effect in reducing the risk associated with high blood cholesterol levels and hypertension.

Obesity is an issue that increasingly needs to be addressed in developing countries, as well as in the developed or ‘Westernised’ world. Type 2 diabetes used to be described as a mainly adult disease, but that is changing as the incidence of obesity is increasing in young people, including children (see Figure 9 for England). This trend extends across the globe – even in countries such as Thailand and China, home to traditionally slender people. While awareness of the problem is growing, there is very limited guidance on what can be done to reverse or stem the problem.

Figure 9: The increase in obesity in children in England between 1995 and 2005

4.4.1 Measures of adiposity

The amount of lipid stored within the body – an individual's adiposity – can be indirectly measured. Body shape (e.g. ‘apple’ or ‘pear’ shapes), waist-to-hip ratio, waist circumference and body mass index (BMI) are all used to classify obesity and being overweight, although BMI is the most common. Everyone should aim to have a body weight within the normal range for their height. Slightly different ranges apply between populations due to different body shapes. It is worth noting that there is increasing scientific evidence that excess abdominal adiposity may be more associated with cardiovascular disease risk than the general degree of adiposity throughout the body (Iacobellis and Sharma, 2007). Thus where the lipid is stored within the body may have more bearing on cardiovascular disease risk than how much lipid is stored. Some scientists and clinicians are now suggesting that the waist-to-hip ratio or the waist circumference should be used in conjunction with BMI when considering cardiovascular disease risk factors.

In general, people who are overweight need to reduce their calorie intake in a balanced way and to increase the amount of exercise that they take in order to burn up calories. Moderate physical activity is generally considered to be 30 minutes of activity per day, e.g. taking a brisk walk. Exercise in itself improves blood glucose control, even when no weight changes are occurring, so it is equally important for people who are not overweight to take regular moderate exercise to maintain cardiovascular health.