Summary: A long-term study of 23,000 adults from Finland and the UK has found that overweight individuals who lost just 6.5% of their body weight in early midlife and maintained the loss enjoyed significant health benefits over decades. The study, spanning 12 to 35 years, is one of the first to link modest, sustained weight loss with lower mortality outside the context of diabetes prevention.
Researchers emphasize that lifelong weight management — ideally maintaining a BMI under 25 — can substantially improve longevity and health outcomes. These findings provide compelling evidence for the long-term value of consistent lifestyle changes, especially as global obesity rates rise.
Key Facts:
- Sustained Weight Loss: Losing and maintaining just 6.5% of body weight in early midlife reduced mortality risk.
- Long-Term Study: The research followed participants over 12–35 years, offering robust lifespan data.
- Optimal BMI Target: A BMI below 25 throughout life is associated with the greatest health benefits.
Source: University of Helsinki
A University of Helsinki study tracked 23,000 individuals from Finland and the UK, aged 30 to 50 at the outset, over a period of 12 to 35 years.
Health benefits were found in overweight men and women who lost an average of 6.5% of their body weight in early middle age and maintained it throughout the 12–35-year follow-up period.
Weight maintenance is crucial.
“The benefits of lifestyle-based weight management are widely discussed even though studies have found it surprisingly difficult to demonstrate health benefits beyond the prevention of diabetes,” notes Professor Timo Strandberg.
The study he led is now filling this gap.
“I hope the findings will inspire people to see that lifestyle changes can lead to major health improvements and a longer life. This is particularly important today as more people are overweight than when the collection of our research data began 35 years ago.”
The study also supports the view that, for optimal health, a lifelong body mass index (BMI) under 25 is ideal.
The study was published in JAMA Network Open, the open-access journal of the American Medical Association.
About this weight loss and longevity research news
Author: Hannamaija Helander
Source: University of Helsinki
Contact: Hannamaija Helander – University of Helsinki
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Weight Loss in Midlife, Chronic Disease Incidence, and All-Cause Mortality During Extended Follow-Up” by Timo Strandberg et al. JAMA Network Open
Abstract
Weight Loss in Midlife, Chronic Disease Incidence, and All-Cause Mortality During Extended Follow-Up
Importance
Few studies have examined long-term health benefits among individuals with sustained weight loss beyond its association with decreased diabetes risk.
Objective
To examine the long-term association of body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) changes during healthy midlife (ages 40-50 years) with later-life morbidity and mortality.
Design, Setting, and Participants
This cohort study analyzed data from 3 cohorts that included repeated height and weight measurements: the Whitehall II study (WHII; baseline, 1985-1988), Helsinki Businessmen Study (HBS; baseline, 1964-1973), and Finnish Public Sector study (FPS; baseline, 2000). Participants were categorized into 4 groups based on their first 2 weight assessments and followed up for morbidity and mortality outcomes. Data analyses were conducted between February 11, 2024, and February 20, 2025.
Exposures
Midlife BMI change was categorized as persistent BMI less than 25, BMI change from 25 or greater to less than 25, BMI change from less than 25 to 25 or greater, and persistent BMI of 25 or greater.
Main Outcomes and Measures
Incident chronic disease, including type 2 diabetes, myocardial infarction, stroke, cancer, asthma, or chronic obstructive pulmonary disease, was assessed in WHII and FPS, and all-cause mortality was assessed in HBS. These outcomes were obtained from linked electronic health records in national health registries.
Results
There were 23 149 participants, including 4118 men and women (median [IQR] age at first visit, 39 [37-42] years; 2968 men [72.1%]) from WHII, 2335 men (median [IQR] age at first visit, 42 [38-45] years) from HBS, and 16 696 men and women (median [IQR] age at first visit, 39 [34-43] years; 13 785 women [82.6%]) from FPS.
During a median (IQR) follow-up of 22.8 (16.9-23.3) years, after adjusting for smoking, systolic blood pressure, and serum cholesterol at the first evaluation, WHII participants with weight loss had a decreased risk of developing chronic disease (hazard ratio [HR], 0.52; 95% CI, 0.35-0.78) compared with participants with persistent overweight. This finding was replicated after excluding diabetes from the outcome (HR, 0.58; 95% CI, 0.37-0.90).
The corresponding HR in FPS was 0.43 (95% CI, 0.29-0.66) over a median (IQR) follow-up of 12.2 (8.2-12.2) years. In HBS, weight loss was associated with decreased mortality (HR, 0.81; 95% CI, 0.68-0.96) during an extended follow-up (median [IQR], 35 [24-43] years).
Conclusions and Relevance
In this study, conducted when surgical and pharmacological weight-loss interventions were nearly nonexistent, sustained midlife weight loss compared with persistent overweight was associated with a decreased risk of chronic diseases beyond type 2 diabetes and decreased all-cause mortality.
