That is the question and one that is not easy to answer.
In the journal BMJ last month a group of researchers published a paper showing an association between a diet rich in flavonoids and keeping weight gain in check over 24 years. But what conclusions can be drawn from this data? Can you say that eating a diet rich in flavonoids will do the same for you?
Luckily for us, the Science Media Centre website already has expert option about the publication. They have reactions from 3 researchers in the area. The first expert advises caution on drawing too solid a conclusion from the results. Finding an association is not the same as proving that the flavonoids are responsible for this. He does, however, agree that there is growing evidence that flavonoids can cause beneficial changes. The second expert has a similar opinion, this is in line with the current recommendations but also states that this is only an observational study.
The third expert does not sound impressed by the paper. He states that people eating food high in flavonoids probably also eat more fruit and vegetables in general, so why is it the flavonoids that are responsible for the weight loss/control observed?
So what is the take home message? Same as always, eating a diet rich in fresh fruit and vegetables seems to be a safe bet.