Current levels of obesity truncate American lives by four to nine months, report Jay Olshansky and his colleagues in the latest New England Journal of Medicine. If child and adolescent obesity continue to run rife, another two to five years will be lopped off our life span in the coming decades, dramatically reversing the rise in U.S. life expectancy seen over the past two centuries. Scientists previously expected average American life expectancy to reach 100 years by 2060. “Looking out the window, we see a threatening storm—obesity—that will, if unchecked, have a negative impact on life expectancy,” Olshansky and his colleagues write in their paper.
Today two-thirds of American adults are obese or overweight, as are a quarter to a third of American children. This adds up to a 3.3-fold increase in childhood obesity over the past 25 years, mostly due to couch-potato lifestyles and the surging sales of fast, fizzy, and junky food.
Obesity increases the risk of heart disease and cancer and is associated with hypertension, asthma, and gastrointestinal problems. It has sparked an epidemic of type 2 diabetes in children, which has increased tenfold over the past 20 years. Having diabetes in adulthood increases the risk of heart attack and shortens lives by about 13 years. Other diabetes-related complications include renal failure, limb amputation, stroke, and blindness. The cost of treating such medical problems will only go up as the age of onset drops.
Research suggests that obesity hits younger people harder than the old. “Among older people, being overweight has some protective things: It makes your bones stronger, makes you able to survive chronic illness better. That’s not so in young people,” says Douglas Passaro, an epidemiologist at the University of Illinois at Chicago who worked with Olshansky. “In younger people, it’s almost all downside and no upside. [Obesity] increases the risk of diabetes and heart disease. It turns middle-aged people into really old people in terms of their mortality rate.”
There is hope for a turnaround. Passaro believes the same factors that help fuel the obesity epidemic in young people, like being impressionable and susceptible to advertising, could be used to shave weight off their generation: “To promote healthy eating habits and decrease the drive to go to the drive-through will have more of an effect on younger people, and that’s a good thing.”
