America's obesity epidemic is so deeply rooted that it will take dramatic and systemic measures - from overhauling farm policies and zoning laws, to introducing a soda tax - to fix it, the Institute of Medicine said in 2012. Reuters

People who are overweight could lose up to three years off their lives, and extremely obese people can expect to trim up to eight years, new research on the health effects of obesity has found. The inverse link between life expectancy and obesity was most astounding on younger people between the ages of 20 and 29, according to a study published Friday in the journal Lancet Diabetes and Endocrinology.

"The pattern is clear,” Steven Grover of McGill University in Canada, which led the study, said in a statement. “The more an individual weighs and the younger their age, the greater the effect on their health, as they have many years ahead of them during which the increased health risks associated with obesity can negatively impact their lives." The main sources of death related to extreme obesity were Type 2 diabetes and cardiovascular disease, scientists found. The research was funded by the Canadian Institutes of Health Research.

The study is one of many to draw parallels between obesity and poor health and comes at a time when obesity rates in the U.S. and elsewhere are at an all-time high. "How many more wake-up calls do we need?” Barbara Dinsdale of the charity Heart Research UK, told the BBC. "This research study yet again supports the clear message that by becoming obese you not only take years off your life, but also … [experience] more years in poor health rather than enjoying a happy, active and productive life."

In addition to decreased life expectancy, the study found that obesity reduced a person's number of “healthy life years” – years free from diabetes or heart problems. When comparing the life expectancies of healthy men between the ages of 20 and 39 to those of obese men in the same age group, scientists discovered that obese men spent an average of 18.8 more years living with poor health. Obese women in the same age group spent 19.1 more years battling health problems than women with healthy weights.

Researchers analyzed data from the U.S. National Health and Nutrition Examination Survey, which aims to track health changes of individuals over time, to make their conclusions.

Previous research has linked obesity with decreased life expectancy. A study from the U.S. National Institutes of Health in July noted that the risk of dying from various health complications, including stroke, kidney and liver disease, increased “continuously” with increased body mass index, calculated by taking a person’s weight divided by his or her height.