Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health (WHO 2010). The fundamental cause of obesity and overweight is an energy imbalance between calories consumed and calories expended. Global increases in overweight and obesity are attributable to a number of factors including: a global shift in diet towards increased intake of energy-dense foods that are high in fat and sugars and a trend towards decreased physical activity due to the increasingly sedentary nature of many forms of work, changing modes of transportation, and increasing urbanization. The WHO recommends using the body mass index (BMI), which is defined as the weight in kilograms divided by the square of the height in meters (kg/m2), to assess the level of overweight and obesity. At present, the WHO defines overweight as a BMI equal to or more than 25, and obesity as a BMI equal to or more than 30. The range of 18.50 to 24.99 is considered as normal. For Asia-Pacific region, the WHO recommend different ranges (WHO 2000). BMI cut-points provide a benchmark for individual assessment, but must be regarded as a rough guide for adults (WHO 2006). The BMI criteria used for children and teens are different from those used for adults
