Preventive Medicine Column

Dr. David L. Katz

If you have tropical fish and you don’t feed them, it isn’t long before they are, well, feeding the fish, if you know what I mean.  Creatures eat, or they die.  So presumably, we know what to feed tropical fish.

Those remarkable zookeepers seem to know what to feed just about anybody.  Their charges, after all, range from koala bears, to gibbons, to giant pandas, to lions, tigers, bears, owls, pythons, hyenas and spiny anteaters (well, that last one is something of a give-away at feeding time, admittedly).

We understand that whatever the quirks and idiosyncrasies of individual koala bears, to say nothing of spiny anteaters, they are in fact all members of the same species, adapted to the same basic diet, and should dine accordingly.  And so, without great contention or clinical trials, it’s eucalyptus leaves all around.

We are creatures, too. Differ though we may from one another, we are all substantially the same. We are a species.  In light of our capacity to feed essentially every other species on the planet appropriately-how plausible is it, really, that we are as clueless as we seem about feeding ourselves?

That we do seem clueless doesn’t require much defense.  First, there is the flagrant support of modern epidemiology.   Both obesity and diet-related chronic disease are rampant, suggesting we either don’t know what we’re doing, or don’t do what we’re knowing.  Second, search for dietary guidance by any means you like and you will topple into such a vast cacophony of competing contentions that it makes the vituperative U.S. Congress sound like the Vienna Boys Choir.

But we are not clueless about the basic care and feeding of Homo sapiens despite the popular diet book that blames it all on meat competing with the popular diet book that blames it all on wheat competing with the popular diet book that blames it on just sugar competing with the popular diet book that says all grains suck.

Some months ago, I was privileged with an invitation to write a scholarly paper for the peer-reviewed journal, Annual Review of Public Health, entitled “Can We Say What Diet is Best for Health?”  The paper, which comes out in March, has a bibliography with 167 entries, representing a wide array of sources about diverse diets, reviewed with an earnest attempt at dispassionate objectivity.  Even this long list of citations is a drop in the proverbial bucket, and is truncated at 167 because the journal had no space for more.  I, along with a team of assistants, am now nearing completion of the 3rd edition of my nutrition textbook for health professionals, Nutrition in Clinical Practice, and that source will have between 7,000 and 10,000 references, all in service of the same goal: establishing the facts about diet and health.

Those facts, derived from modern research, historical experience, and evolutionary biology alike all support a clearly established theme of healthful eating for Homo sapiens rather well expressed by Michael Pollan as: eat food, not too much, mostly plants.  With stunning consistency, a vast literature exploring diverse cultures, dietary patterns, and health outcomes, returns again and again to this theme.  Off the reservation are highly processed, glow-in-the-dark foods.  Always on are vegetables, fruits, beans, legumes, nuts, and seeds.  Almost universal are whole grains.  Lean meats, fish, seafood and dairy come and go with variations on the theme, but there is clearly room for them for those so inclined.

In fact, it’s a beautifully commodious scenario.  The basic theme of optimal eating is quite clearly established, while the best variant on that theme most certainly is not- leaving each of us where we belong, holding the oven mitt.  Variations on the theme allow us to invoke the common principles of healthful eating, while making personalized choices conducive to loving the food that loves us back.  Variations on the theme readily accommodate your choice of a vegetarian, low glycemic, Mediterranean, Asian, or Paleo diet.

But then how it can it be that one book so convincingly makes the case that all our ills are due to eating animals, while another vilifies sugar just as convincingly, and yet another impugns all grains?  Authors need only decide what they believe in advance, and select out the studies, however few from among however many, that support it. Sorry, folks, but pseudo-erudition in support of dietary nonsense really is that easy- and while the authors are the richer, the rest of us are the poorer, fatter and sicker for it.

The notion that we are as clueless as we generally seem about the basic care and feeding of Homo sapiens is implausibly far-fetched and, in a word, baloney. And perhaps that explains everything.  We can’t think straight about what to feed ourselves because we are all suffering the bloat and cognitive impairment of baloney overdose.  We don’t need much of a clue about what our diet ought to be to know it should be something other than this.




Dr. David L. Katz