As the decade draws to a close, hopes that just eating a bit more broccoli will help banish disease appear to be waning - and some are urging a rethink of how we approach the many messages about diet and disease.
The five-a-day campaign - with its roots in the US - hit England in 2003 with the aim of increasing fruit and vegetable consumption as a "national priority". But the role these play in protecting us from cardiovascular disease and cancer above and beyond acting as substitutes for more calorific fare now seems murkier than it did then.
A major piece of recent research found that while vegetarians did seem to develop fewer cancers than meat-eaters they were not protected against bowel cancer - one of the most common forms of the disease and one which had been thought to be particularly influenced by the consumption of red and processed meat.
"We're clear on obesity - and also alcohol - as disease risk factors," says Tom Sanders, Professor of Nutrition & Dietetics at King's College, London.
"But the suggestion of a reduced risk with increased fruit and vegetable intake once you take out all the other factors is much harder to prove. We are pretty much drawing a blank. One of the myths is that fruit is bursting with minerals - it's not. It's essentially vitamin C and potassium - and most of us really have enough of these without five-a-day."