The habits people develop in early adulthood may shape their weight for years to come.
A new study from researchers at Tufts University published in Nutrients suggests that individuals who maintain healthier lifestyle patterns from their late teens into adulthood tend to gain less weight over time than those whose habits remain less healthy.
The findings come from a long-term study tracking Tufts students from the start of college into adulthood, examining how patterns of diet, physical activity and sleep relate to weight changes over an 11- to 20-year period.
Researchers found that people whose habits remained consistently healthy gained the least weight on average, while those who maintained the least healthy patterns gained the most.
“College is this critical window when young people have newfound autonomy and are making their own decisions around physical activity, diet, and other health behaviors more so than in earlier years,” said Dan Hatfield, an adjunct assistant professor at the Tufts Friedman School of Nutrition Science and Policy and senior author of the study.
To examine how lifestyle patterns change over time, the research team analyzed data from the Tufts Longitudinal Health Study. Between 1998 and 2007, 4,641 incoming Tufts students completed a survey before starting college that asked about their diet, physical activity and sleep habits. Participants also reported their height and weight.
More than a decade later, in 2018, researchers followed up with alumni from the original group. A total of 970 participants completed a similar survey describing their current lifestyle behaviors and weight.
Using statistical analysis, the researchers grouped participants into three categories based on their behavior patterns: healthy, moderately healthy and minimally healthy. Healthier groups tended to report higher intake of fruits and vegetables, more physical activity and better sleep habits.
The researchers then examined how individuals’ behavior patterns changed between the precollege and adulthood surveys. About half of participants maintained similar patterns across the two time points, while roughly one-third reported lifestyle habits that worsened over time and about 18.6% improved their patterns.
Over the study period, weight gain was common. The prevalence of overweight more than doubled, rising from 12% before college to 26% in adulthood. Obesity increased from 2% to 8%.
Despite those increases, rates of overweight and obesity in the study population remained lower than the national average, which the researchers noted may reflect the characteristics of the study group.
When the team examined how lifestyle trajectories related to weight outcomes, clear differences emerged. Participants who consistently maintained healthier behaviors tended to gain less weight than those who remained in the minimally healthy group.
Christina Economos, dean of the Tufts Friedman School of Nutrition Science and Policy and a co-author of the study, said long-term research helps improve understanding of the many factors involved in obesity.
“With each study like this, we build our own understanding of a condition that has vexed individuals and policy-makers alike,” Economos said.
The researchers say the findings highlight the transition to adulthood as an important stage for establishing health habits that may persist later in life. Because many young adults attend college, campuses may provide opportunities to support healthier behaviors through initiatives such as nutrition labeling in dining halls, sleep education and physical activity programs.
The authors noted several limitations. Lifestyle behaviors and body weight were self-reported, which can introduce measurement errors. In addition, only a portion of the original participants completed the follow-up survey, and the study population consisted entirely of Tufts students and alumni, who may not reflect the broader U.S. population.
Even so, the long follow-up period offers insight into how lifestyle patterns established in early adulthood may influence weight trajectories years later.
The researchers reported that the study was supported by funding from Tufts University.