[DanBC]

> How to reliably lose weight and keep it off is still basically an unsolved problem.

No, it really isn't.

"Eat less calories than you burn". It's that simple. Even if we include various viruses and bacteria that help us lose weight or help us gain weight, and we include various disorders that help us lose weight or gain weight, the answer is still "Eat less calories".

Unless of course you're saying that getting people to change behaviour, for ever, is tricky. In which case I agree with you.