This particular statistic has a ton of problems. It's impossible to disassociate the various causative pathways that land you at a BMI below 25. A ton of them involve diseases and chronic conditions.
Unfortunately, it's very hard to impossible to RCT this. And if a study has no RCT, take it with as much salt as your diet allows.
You definitely don't want to intentionally gain weight on the basis of this. If weight control is easy for you, I would personally strive for a lower BMI.
If losing weight below 25 is hard for you and your body just seems to refuse to do it, then you might be OK at 25.
Unfortunately, it's very hard to impossible to RCT this. And if a study has no RCT, take it with as much salt as your diet allows.
You definitely don't want to intentionally gain weight on the basis of this. If weight control is easy for you, I would personally strive for a lower BMI.
If losing weight below 25 is hard for you and your body just seems to refuse to do it, then you might be OK at 25.