The definition of obesity varies depending on what one reads. In general, overweight and obesity indicate a weight greater than what is healthy. Obesity is a chronic condition defined by an excess amount of body fat. A certain amount of body fat is necessary for storing energy, heat insulation, shock absorption, and other functions.
Body mass index best defines obesity. A person’s height and weight determines his or her body mass index. The body mass index (BMI) equals a person’s weight in kilograms (kg) divided by their height in meters (m) squared (more information will be found later in the article). Since BMI describes body weight relative to height, there is a strong correlation with total body fat content in adults. An adult who has a BMI of 25–29.9 is overweight, and an adult who has a BMI over 30 is obese. A person with a BMI of 18.5–24.9 has a normal weight. A person is morbidly obese (extreme obesity) if his or her BMI is over 40.
Several factors can play a role in gaining and retaining excess weight. These include diet, lack of exercise, environmental factors, and genetics. Some of these factors are discussed briefly in the following section.
However there are many factors that can influence our weight and predispose us to being overweight and we can sometimes have little or no control over. Our environment, as well as social and psychological reasons can also influence our weight as well as biological reasons.
Environmental influence- we live in an environment today which makes us vulnerable to becoming overweight as food is now readily available and cheap. The environment has also changed in terms of how much physical work we now undertake.
Social factors- changes in lifestyle e.g. ability to give up smoking, undertake physical activity, the influence and impact of our family and relationships.
Psychological factors — early childhood experiences as well as our level of stress in our lives can increase our vulnerability to become overweight. Our eating habits and impact of previous attempts can also be a factor.
Biological — There can be a genetic influences as well as medication and ill health can also influence weight gain.
The more you understand the influences on your eating behaviour and weight, the more prepared you will be to make the changes to your lifestyle.