Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2).
According to WHO definition a BMI greater than or equal to 25 is overweight and
a BMI greater than or equal to 30 is obesity
Although several classifications and definitions for degrees of obesity are accepted, the most widely accepted classifications are those from the World Health Organization (WHO), based on BMI. The WHO designations include the following:
* Grade 1 overweight (commonly and simply called overweight) - BMI of 25-29.9 kg/m2
* Grade 2 overweight (commonly called obesity) - BMI of 30-39.9 kg/m2
* Grade 3 overweight (commonly called severe or morbid obesity) - BMI greater than or equal to 40 kg/m2
There are various factors that can contribute to obesity.
Obesity does not just happen overnight, it develops gradually from poor diet and lifestyle choices and, to some extent, from your genes. Some of the major factors are
LACK OF PHYISICAL ACTIVITY
If you are not active enough, you do not use up the energy provided by the food you eat, and the extra calories are stored as fat instead.
LIFESTYLE CHOICES
Lifestyle choices are an important factor in influencing your weight. Eating more calories than you need may be down to unhealthy food choices. For example, unhealthy food choices could be:
* eating processed or fast food that is high in fat,
* not eating fruit, vegetables and unrefined carbohydrates, such as wholemeal bread and brown rice,
* drinking too much alcohol - alcohol contains a lot of calories, and heavy drinkers are often overweight, and
INLUENCE OF GENES
Some genetic conditions can increase your appetite, so you end up eating too much. There are also genes that determine how...