The Organization for Economic Cooperation and Development (OECD) recently released its 2014 Obesity Update, which analyzes the relationship between economic development and obesity. They found that, until 1980, fewer than one in ten people were obese in OECD countries. In the following decades, rates doubled or tripled, and are continuing to grow.

As income, education, and living conditions have improved over time, height and weight have also been increasing. Up to a certain point, weight gains were beneficial for increasing health and longevity of human ancestors. However, a line has been crossed into unhealthy and excess weight that is detrimental to health and longevity.

Reuters reports that women and the poor have been hit the hardest by the recent economic crisis, which has also been tied to increases in obesity rates. A review of available data showed that the global recession that struck in 2008 forced many families in harder-hit nations to cut back spending on food, especially healthier and more expensive options such as fruits and vegetables, in favor of cheaper, less healthy options.

According to the World Health Organization (WHO), overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A crude population measure of obesity is the body mass index (BMI), a person’s weight (in kilograms) divided by the square of his or her height (in meters). A person with a BMI of 30 or more is generally considered obese. A person with a BMI equal to or more than 25 is considered overweight.