A new study from the University of Helsinki suggests that losing weight in early middle age — and keeping it off — can bring long-term health benefits and may help people live longer.
The research followed more than 23,000 men and women from Finland and the UK who were between 30 and 50 years old when the study began.
Over a follow-up period of 12 to 35 years, the scientists looked at how changes in body weight related to long-term health and lifespan.
They found that overweight adults who lost an average of 6.5% of their body weight in early middle age and maintained that loss throughout the decades had significantly better health outcomes.
The results suggest that steady, long-term weight maintenance — not just short-term dieting — is key to gaining the benefits.
Professor Timo Strandberg, who led the study, said that while many people talk about the benefits of weight management, most long-term studies have struggled to show clear health improvements beyond preventing diabetes.
This research helps fill that gap.
“I hope the findings will inspire people to see that lifestyle changes can lead to major health improvements and a longer life,” Strandberg said. “This is particularly important today as more people are overweight than when our research data collection began 35 years ago.”
The study also adds to the evidence that keeping a healthy body mass index (BMI) over a lifetime is ideal. BMI is a measure of body fat based on height and weight. According to the results, the best health outcomes were linked to maintaining a BMI under 25 from early adulthood onward.
While the study does not suggest extreme or rapid weight loss, it emphasizes the benefits of moderate, sustainable changes. Losing 6.5% of body weight is considered an achievable goal for many. For example, for someone who weighs 90 kilograms (about 198 pounds), this would mean losing just under 6 kilograms (about 13 pounds) — and keeping it off.
The researchers did not focus on specific diets or exercise plans but looked at weight patterns over time. This means the exact lifestyle changes that worked for individuals varied, but the key was consistency. People who managed to avoid regaining the lost weight saw the most benefit.
These findings could be particularly valuable for health professionals advising patients in their 30s, 40s, and 50s. Middle age is a period when weight gain is common due to changes in metabolism, hormones, and activity levels. But this study shows that even modest weight loss, if maintained, can make a difference in health decades later.
The research was published in JAMA Network Open, the open-access journal of the American Medical Association. While more studies are needed to explore how different approaches to weight loss work in the long run, this work provides strong evidence that keeping a healthy weight over many years can contribute to living a longer, healthier life.
This study is important because it focuses on weight loss in midlife, a time when many people already have established routines and may feel it’s too late to make a big difference to their health. The findings challenge that belief, showing that even modest, sustainable weight loss can have long-term benefits if maintained.
It also reinforces the message that the goal is not just to lose weight, but to keep it off for good. Public health programs and personal weight management plans may benefit from emphasizing maintenance strategies as much as the initial weight loss.
If you care about weight loss, please read studies about Scientists find secrets to long-term weight loss success and findings of Weight loss surgery linked to this mental disease.
For more information about obesity, please read studies about Obesity drugs can help prevent weight regain after weight loss surgery and findings of Research shows big hidden cause of obesity.
The study is published in JAMA Network Open.
Copyright © 2025 Knowridge Science Report. All rights reserved.
