New Delhi, Feb. 5 -- For years, weight loss has been a central focus of health discussions but new research suggests that being in shape is far more important for longevity than being thin. A comprehensive study has found that being out of shape significantly increases the risk of early death-regardless of age or body mass index (BMI).

The largest study of its kind, recently published in the British Journal of Sports Medicine, analyzed data from nearly 400,000 middle-aged or older individuals across multiple countries. Researchers discovered that those who were aerobically fit had a much lower risk of premature death-even if they had obesity-compared to those with normal weight but poor fitness levels.

"This tells us that it's much more...