(Medical Xpress) -- Those 25-year-olds who are overweight now but think they will be fine as long as they lose weight eventually might need to reconsider. A study appearing online in the Journal of Adolescent Health finds that people who are overweight during young adulthood are likely to die earlier than others.

“Young adults are so much heavier now than they were 20 years ago,” said June Stevens, Ph.D., lead study author. “Our results really make me concerned that getting heavy early in life could translate into a shorter lifespan for many Americans.”

The risk of dying was 21 percent higher in those with a higher body mass index (BMI). Moreover, after adjusting for other risk factors such as smoking status, physical activity and alcohol consumption, it was 28 percent higher.

“If you made everybody’s gain over those intervening years the same, there was still an effect of being heavier at age 25 on increased mortality,” said Stevens, nutrition and epidemiology professor at the University of North Carolina, Chapel Hill. “BMI in matters. You can’t just make up for it by losing weight later. You need to be concerned about your BMI throughout your young adulthood.”

Carrying a higher BMI or being overweight at 25 had a greater impact on African-American women than white women and on men compared to women. Yet, the influence of obesity early on in life was negligible in black men when adjusting for weight change throughout adulthood.

“Why would changes in weight from middle adulthood to young adulthood cancel out the effect of weight at age 25 in African-American men?” Stevens said. “I don’t really have an answer for that.”

Catherine Loria, a nutritional epidemiologist at the National Heart, Lung, and Blood Institute at the National Institutes of Health, said this study underscores the importance of adopting healthy habits earlier in life and sustaining it.

“The bottom line here is for all of these ethnic groups, weight in young adulthood was associated with mortality,” Loria said.

More information: Stevens, J., et al. Body Mass Index at Age 25 and All-Cause Mortality in Whites and African Americans. J Adol Health online, 2011.