I'm broadly healthy. I've never been a member of a gym, but I play football twice a week and a racket sport once a week. I rarely eat out so I tend to eat home cooked food or white bread sandwiches. I eat fruit almost every day too. But I'm naturally sceptical.
So I have never believed this five-a-day nonsense. I've done a little research, and I still can't find the very first recommendation for it. Let me know if you can point me there. Yet people, apparaently rational sensible people, swear by this rule.
In the absence of a confirmed original reference, I suggest a theory. I suggest that some well meaning government advisor decided that a simple "eat more fruit and veg" message would not work for the mindless sheep who need explicit holy instructions to guide their aimless lives. So he or she decided that five a day was the clear message. But amazingly, some fools took it literally, and the virus spread. Now it is "truth". A normal balanced diet, like an evolved world, is just too complicated for some people to understand. If they've been pigging out on burgers all day then five portions of fruit juice in the evening will "balance" it.
Except from libertarian slobs trying to justify their unhealthy lifestyles, we rarely see articles criticising this five-a-day rule. Yesterday the Guardian finally did. But it still doesn't come close to the derision I feel for those who treat the rule like religion.