Eat less, live longer and healthier

A recent study determines that obesity currently reduces life expectancy by approximately four to nine months. The researchers also predict that the rapid rise in obesity among children and teenagers in the past 30 years will have life-shortening effects in the future -- perhaps enough to offset any improvements in longevity from anticipated advances in biomedical technology. (Related article: Health emergency developing in the USA)

Researchers also believe the life-shortening effect of obesity could rise so rapidly in the United States -- from two to five years in the next 50 years -- that it may eventually exceed the current life-shortening effects of cancer or ischemic heart disease. The findings are contrary to what some scientists predict about human life expectancy, which assumes that past increases will continue indefinitely. Most forecasts of life expectancy are based on historical trends, but the authors conclude that such estimates fail to consider the obesity epidemic. (Related article: How to lose weight easily?)

Jay Olshansky and his colleagues argue that current extrapolation models used to predict life expectancy do not take into consideration the health status of people currently alive. Longevity predictions are crucial for health policy and for economic policy as well. "One of the consequences of our prediction is that Social Security does not appear to be in nearly as bad a shape as we think," Olshansky said. "The obese may be inadvertently 'saving' Social Security, but the obese themselves and the health care system that cares for them will pay a very heavy price in terms of higher death rates and escalating health care costs."

To estimate the current impact of obesity on life expectancy, the researchers calculated how much longer people would live if obesity did not exist. To do this, they used recently published health statistics and assumed that everyone who is currently obese acquired the body mass index of people who have the lowest risk of death. (Related article: Lose weight, have fun)

By calculating years-of-life-lost due to obesity and combining that with estimates of the prevalence of obesity in younger generations, the authors were able to illustrate that in the coming decades the risk of death from obesity-related causes is about to rise. The hardest hit will be minorities, because of limited access to health care and because they have experienced the most rapid increases in obesity in recent years, according to the authors. (Related article: Diets for happy weight)

It is well documented that obesity is associated with an increased risk of diabetes, heart disease, cancer and other complications. Obesity and overweight are the second leading cause of preventable death in the United States. And the largest increases in obesity have occurred among children and minorities. (Related article: Makeovers are not just about losing weight)

Body weight is affected by many genetic, psychological and environmental factors that influence diet or physical activity levels, says Dr. David Ludwig, associate professor and director of the Obesity Program at Children's Hospital Boston and a co-author of the study. For children in particular, fast food, sugar-sweetened beverages and other high-calorie/low-quality junk foods are major contributors to obesity.

"These adverse changes in diet have been driven by a multi-billion dollar marketing campaign by the food industry aimed at young children," said Ludwig. "Cutbacks in funding for regular, mandatory PE classes and limited insurance reimbursement for obesity prevention and treatment are also contributory."

The researchers predict that unless effective interventions are developed to reduce obesity, children today may live less healthy and shorter lives than their parents. "In addition to the enormous economic costs of obesity, the personal toll is incalculable," Ludwig said. "The rapidly escalating prevalence of childhood obesity and its most feared complication, Type 2 diabetes, raises the prospect of heart attack becoming a common condition of young adulthood."

The authors expect that this study will raise awareness of the importance of increased funding for obesity research and treatment, especially in children. They also point out that new investment into the Social Security system, while at the same time under-funding obesity prevention and treatment, is not sound economic or public health policy.

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