Well, maybe not everything, but a lot of government advice — which may well have been a major factor in the rise of obesity — was based on very little empirical evidence:
Whenever standard nutritional advice is overturned — as it has been this week by a study which effectively rubbished government guidelines limiting the intake of dietary fat — I am instantly reminded of a scene in the Woody Allen film Sleeper, first released when I was 10. I expect a lot of people my age are.
In the film Allen plays Miles, a cryogenically frozen health food store owner who is revived 200 years later. Two scientists are puzzling over his old-fashioned dietary requirements, unable to comprehend what passed for health food back in 1973. “You mean there was no deep fat?” says one. “No steak or cream pies, or hot fudge?”
“Those were thought to be unhealthy,” says the other scientist. “Precisely the opposite of what we now know to be true.”
This was meant to be a joke rather than a prediction, but it’s beginning to look as if we may not have to wait until 2173 to see it validated.
[…]
Of course the new study isn’t comprehensively refuting the association between high saturated fat intake and heart disease; it’s just pointing out that dietary guidelines first adopted in the mid-1970s were not, on reflection, based on any real evidence. In terms of what one should and shouldn’t be eating, I sometimes feel as if I’ve spent the past 30 years in a freezer.