Obesity is no longer considered a cosmetic issue that is caused by overeating and a lack of self-control. The World Health Organization (WHO), along with National and International medical and scientific societies, now recognize obesity as a chronic progressive disease resulting from multiple environmental and genetic factors. The disease of obesity is extremely costly not only in terms of economics, but also in terms of individual and societal health, longevity, and psychological well-being. Due to its progressive nature, obesity requires life-long treatment and control.
A simple way to measure obesity is by using Body mass index (BMI), commonly used to classify overweight and obesity in adults. It is defined as the ratio of body mass (in kilograms) to square of body height (in meters).
What causes obesity and overweight
Although there are genetic, behavioral and hormonal influences on body weight, obesity occurs when more calories is consumed than calories expended through exercise and normal daily activities. Body stores excess calories as fat. However, in general, the principal causes of obesity are inactivity and unhealthy diet and eating habits.
A number of other conditions associated with obesity contribute to the progression of the disease.
Obesity reduces mobility which reduces the number of calories burned, it can also reduce sleep duration due to number of conditions that impair sleep quality such as pain, sleep apnea and other breathing problems.
Weight gain also contributes to the development of diseases such as hypertension, diabetes, heart disease, osteoarthritis and depression, and these conditions are often treated with medications that contribute to even further weight gain.
A low calorie diet is the primary treatment for overweight and obesity, but, dieting is also a contributor to obesity progression. Dietary weight-loss causes biological responses that persist long-term and contribute to weight regain. One of these responses affects energy balance. When a person loses weight, the body "thinks" it is starving and energy expenditure is reduced in order to conserve calories. Another biological response that occurs with dieting involves changes in fat metabolism that reduce the body's ability to burn fat and increase the capacity for fat to be stored in adipose depots (fat storage depots). With dietary weight-loss, the amount of dietary fat the body burns is reduced by approximately 50 percent.
Stats on obesity
According to WHO some recent global estimates follow.
- In 2014, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 600 million were obese
- 39% of adults aged 18 years and over were overweight in 2014, and 13% were obese
- The worldwide prevalence of obesity more than doubled between 1980 and 2014
- Worldwide at least 2.8 million people die each year as result of being overweight or obese