Losing weight during this life period is linked to a longer lifespan

A new study from the Boston University School of Public Health is giving new meaning to the phrase “no time like the present.”

When it comes to losing weight and adopting a healthier lifestyle, it’s often said that it’s never too late to make a positive change. According to the team at BU, however, that may not be true after all. 

Researchers conclude that obese individuals who lose enough weight between early and mid-adulthood (roughly mid-20s through mid-40s) to lower their BMI ranking from “obese” to “overweight” significantly lower their risk (54% less likely) of passing away at an early age. Unfortunately, though, the same weight loss after mid-age does not appear to significantly reduce the risk of early death.

All in all, it appears an individual’s body weight between early and mid-adulthood has a much more prominent impact on life expectancy and longevity than at any other age. So, while it’s always tempting to say “maybe tomorrow” to losing weight today, these findings represent a compelling reason for middle-aged adults to stop wasting time regarding weight loss goals.

Simply put, put it off long enough, and you may wake up one day and it’ll be too late to make a significant difference.

“The results indicate an important opportunity to improve population health through primary and secondary prevention of obesity, particularly at younger ages,” says corresponding study author Dr. Andrew Stokes, assistant professor of global health at BUSPH, in a release.

Based on their calculations, the study’s authors say 12.4% of premature American deaths may have been caused by a high BMI at some point between early and mid-adulthood.

A gigantic dataset encompassing 24,205 people was used for this research. That information had originally been collected between 1998-2015 for the National Health and Nutrition Examination Survey. All participants were then observed for an average follow-up period of 10.7 years.

Each person included in the data had been between 40-74 years old at the time they entered the study. A total of three BMI readings were included for each person; their BMI at the age of 25, their BMI 10 years before enrolling in the research project, and their BMI when they entered the project. 

With all of that information in hand, the research team looked at the specific relationship between BMI changes over lifespan and the likelihood of death throughout the study observation period.

After accounting for other factors that may have influenced their calculations (gender, smoking habits, education level), researchers recognized a clear pattern.

Adults whose BMI improved from “obese” to “overweight” between the age of 25 and roughly 44 years old were 54% less likely to have passed away during the follow-up period than adults who stayed within the “obese” range throughout adulthood. 

From a mortality risk perspective, adults who lost weight and improved from “obese” to “overweight” had about the same risk of early death as adults who were consistently within the “overweight” bracket of BMI their entire lives. This is a notable observation because it suggests the effects of obesity can indeed be reversed, as long as weight loss takes place early enough in life.

“The present study provides important new evidence on the benefit of maintaining a healthy weight across the life course,” comments lead study author Dr. Wubin Xie, a postdoctoral associate in global health at BUSPH.

The study’s authors believe 3.2% of the deaths seen among study participants throughout the observation period could have been avoided if everyone with an “obese” BMI at the age of 25 had been able to lower their weight to “overweight” levels by midlife.

Why is losing weight later on in life so inconsequential in terms of lifespan? Researchers can’t say for sure but speculate that much of the weight loss experienced among older adults and the elderly occur because of health problems and disease.

“Although this study focused on preventing premature deaths, maintaining a healthy weight will also reduce the burden of many chronic diseases such as hypertension, diabetes, heart disease, and even cancer,” adds study co-author Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women’s Hospital, and professor of medicine and Michael and Lee Bell Professor of Women’s Health at Harvard Medical School.

The full study can be found here, published in JAMA Network Open.