The health consequences
The consequences of obesity are serious and risk increases progressively as BMI rises. Obesity is among the most important risk factors for type 2 diabetes, heart disease, stroke and some forms of cancer, making it one of the leading preventable causes of death worldwide and one of the most significant public health challenges of the 21st century. More and more diseases are being linked to obesity, including asthma, osteoarthritis and sleep apnoea.
Abdominal obesity, characterized by increased fat under the skin of the belly and between the abdominal organs (visceral obesity), is considered especially harmful, as it is particularly powerful in increasing the risk of heart disease and diabetes. It is increasingly clear that disturbed functioning of adipose tissue may be an important factor in obesity-related health risks. As people get fatter and their fat cells expand, the adipose tissue becomes less able to store fat and the body starts storing it in other tissues, such as muscle and liver, which may disturb cell function and lead to disease. Also, it has become clear that adipose tissue is a very active organ, secreting hormonal signals that may affect metabolism in other organs.
Recently, a major scientific review has concluded that obesity is clearly related to decreased life expectancy. Studies indicate that despite the shorter life expectancy, obese people have more unhealthy life-years, meaning they spend more of their life chronically diseased, work-disabled and with an impaired quality of life. Several studies estimate that 2%-10% of direct healthcare costs in western populations are attributable to obesity. The cost of overweight is estimated to be higher in many countries than that for type 2 diabetes or hypertension.
Social stigma is another consequence of obesity and the condition has been linked with depression in some people.
