The USDA’s “food pyramid” eating guide was introduced as an incredibly complicated way of saying “eat more fruits and vegetables, eat fewer treats, and especially eat less meat”. But because USDA’s jobs include (a) being the government’s arbiter of nutrition advice and (b) being the U.S.’s main marketing agency for the meat and prepared food industries (and other food industries), there is a wee conflict of interest problem. So though the committee that created the pyramid was trying to offer simple good advice, it had to be buried and convoluted to be politically acceptable.
The trouble was that when people started eating more fruits and vegetables in the U.S., they focused on bananas and potatoes. These are not worthless in terms of micronutrients, but they are about as not-so-good-for-you as you can get and still be a plant that the human body can digest. But just as USDA could not say “eat less meat and more fruits and vegetables”, they could not say “oh, and as an amendment to that last bit of advice, potatoes are not really a vegetable and bananas are a pretty marginal fruit”. So they thought about it, realized that both potatoes and bananas are whitish, and came up with a new ridiculously complicated and completely absurd bit of advice, one which contained the anti-potato, anti-banana message without the burden of being honest. Or good advice.
They decided to claim that plant foods have different healthful properties that are associated with their color. I suppose it is a bit better than categorizing them based on what frequency they vibrate at or which minor god imbues them with mana, but not a lot better. I laughed out loud for minutes when I first saw the glossy brochure for the “eat colors” advice tacked to the wall (non-ironically, I am sad to say) at the University of Texas School of Public Health.
I should concede that this explanation for the silly bit of advice is just my theory for why it was created – unlike the “eat less meat story” I have never had it confirmed by taking to an insider involved in the decision process.
Why is it so silly as to require an explanation like this? Well consider the advice to eat some red food, which includes such oh-so-similar foods as red onions, apples, watermelon, tomatoes, and red peppers. But make sure the peppers are ripe enough; the less ripe ones (green peppers) are over in the group with lettuce, avocado, and broccoli. Your “orange and yellow” goal can be fulfilled by grapefruit or a sweet potato (not a potato – actually a very nutritious food, but nothing like grapefruit in terms of nutrition). And maize is on the list – yes, that would be the grain we know as corn, whose nutrition is similar to that of other grains. Oh, and the grapefruit has to be yellow, because pink grapefruit is back in the red group.
I am not making this up. I wish I could take credit for it as made-up satire.
There is some good advice to be found in “all else equal, eat brightly colored plant food”. But having similar colors (as defined by Crayola) represents little in terms of having nutritional similarity, except in cases where they are basically the same plant, like broccoli, kale, and cauliflower (oops).
But how do we explain the ADA embracing this silly political game that they – not being obliged to avoid offending the potato industry – did not have to subscribe to? All I can think is that it is because few dietary researchers and clinicians are great scientific thinkers, and those who rise to positions of organizational influence are probably worse than average. I hate to be too hard on dietetics people because at least they – unlike physicians who mostly seem to know less about diet than the average newspaper reader should – recognize the tremendous importance of nutrition, food allergies, and other dietary issues. But I can only conclude that they were not expert enough in their own field to know how absurd this advice is.
What is especially hilarious, though, is that ADA borrowed the idea and then, if the current newspaper articles are to be believed, abandoned its purpose: They just left potatoes off of the list. This is perfectly reasonable. A huge improvement over “eat colors” is “potatoes are junk food; eat real vegetables”. But once you already advising against potatoes, the color advice loses its one bit of actual value.
Sadly, lots of people who are trusted as experts take this crap seriously. It is enough to make you seek out a few ambers, stouts, golden lagers, and Belgian whites (not to be confused with brussels sprouts, which are green and thus must be different).