Let me be concrete. Everyone knows that it is better to eat more fruits and vegetables and less processed food. Off the top of your head, how much must one eat to make a difference? Does it help people live longer, or just reduce sickness? Does it help by 1%, 5%, 20%?
If you just read the title of the report it is easy to be cynical and say, "duh, I knew that", but if you read the actual study it surely will give insights that you were not aware of.
But please, do tell us your favorite pet projects they should be studying instead.
After all who cares for factors of longevity, when they could be studying new revolutionary shoe laces, or some new mobile phone bound tech...