Overview

• The study drew on data from over 23,000 British and Finnish adults across three cohorts, with follow-up periods spanning 12 to 35 years.
• Participants who lost an average of 6.5% of their body weight in their 40s experienced a 48% lower risk of chronic diseases and a 19% reduction in all-cause mortality over subsequent decades.
• Protective effects against heart disease, stroke, cancer and lung conditions emerged only after extended follow-up, underscoring the importance of long-term commitment.
• Weight loss was achieved solely through diet and exercise before modern drugs and surgeries were available, highlighting the efficacy of lifestyle interventions.
• As an observational study, it cannot establish causality, and researchers call for further work to clarify how intentional midlife weight loss drives lasting health benefits.