Diet: Guidance Veers from Variety

Diet: Guidance Veers from Variety

David Katz 10/11/2018 3
Advertising Advertising

The holidays are coming in hot (figuratively, and courtesy of climate change, literally as well), with Thanksgiving now under two weeks away. So, of course, all thoughts turn to…weight control.

I hate to say it, frankly; would that it were not true. My traditional health advice about the holidays has been, and remains: let the good times roll. We all need a break, badly, and the therapeutic solace of family, friends, and intimate solidarities. Maybe if we gave ourselves over to the better angels of the holiday season, we could even recall we are all family, however extended, and take up the role of better humans. 

Sadly, though, weight gain, and its prevention, will loom large as ever among the holiday ruminations for many. This is mostly because of our failure to establish a healthy relationship with food, year round, once and for all- and only very slightly because of the episodic perils of holidays per se. The effect is the same however one frames the causes: holiday weight gain is common in a population already suffering widespread ill health due to overweight and obesity. We manage generally both to fret about the menace, and fail to control it- and then hope to set things right with a New Year’s resolution, which also, inevitably fails.

Against that cheery backdrop comes a bit of timely advice, in the form of a Science Advisory, courtesy of the American Heart Association. Their tip regarding diet and weight is this: variety is not your friend.

I will clarify that message and its implications momentarily. First, let’s consider how obvious it already was.

Have you ever been to an all-you-can-eat buffet? Have you ever NOT overeaten at an all-you-can-eat buffet? Has anyone ever not overeaten at an all-you-can-eat buffet? I don’t think so.

Everyone overeats at an all-you-can-eat buffet. I have been pointing out the irony in the all-you-can-eat value proposition to anyone who would listen (my patients, mostly) for years: so, you are going to eat more than you need and get fat at no extra charge, and then probably find yourself willing to spend a small fortune to lose the weight that you gained for free. Where, exactly, is the bargain in that? Wake up, smell the Slimfast, and snap out of it!       

I have noticed no decline in the popularity of all-you-can-eat buffets resulting from my recurring rant. It was worth a shot.

Back to the holidays, let’s consider that upcoming Thanksgiving feast. The common experience, I believe, is to eat until we can eat no more. That’s my plan, certainly, both because our annual feast is great, and because my mother would be disappointed otherwise. So, taking one for the team- I will stuff myself in the traditional manner.

But then a funny thing happens on the way to the Alka Seltzer. I said we eat until we can eat no more, but that’s not quite true. When we can eat no more, we can still eat…dessert. There is usually just enough time between “I couldn’t eat another bite,” and “what’s for dessert” to let out our belts out a notch or two.

That phenomenon is not a hollow leg or extra stomach, but rather a very well-studied trait of the human appetite center, called sensory specific satiety. We tend to fill up in a food and flavor-specific manner. But cross over from the salty, savory delicacies of the Thanksgiving meal to the sweet enticements of the dessert table, and a whole new appetite is activated. 

Perhaps we can capture it all by borrowing a well-known aphorism: familiarity breeds satiety. The perilous corollary is that variety is a goad to gluttony.

This, in effect, is what the American Heart Association concluded. We have long had dietary guidance emphasizing the value of variety, and in their new Science Advisory, based on a thorough review of relevant evidence, the Heart Association is saying: not so much. There is no clear evidence of health benefit by increasing dietary variety, while the risk of weight gain rises with the length of your grocery list. 

Linking this to grocery lists is directly germane. The inventory of the typical supermarket in the United States in the 1970s was roughly 15,000 products. Now, it is nearer to 50,000. Who can name the 35,000 new fruits and vegetables introduced over recent decades?

No one, because that hasn’t happened. Rather, food manufacturers have done three things primarily to expand our dietary choices so copiously. First, they have used the same four ingredients- wheat, soy, rice, and corn (and, importantly, sugar made from corn)- to create thousands of products. This is not genuine dietary diversity; it is pseudo-diversity. The products vary, but the composition of the products varies barely if at all. Most of the alleged “variety” in modern diets is of this type.

Second, manufacturers have exploited every sequential, equally silly variant on the theme of dietary savior or scapegoat (e.g., fat, carbohydrate, fructose, gluten, GMOs, etc.) to capture the public imagination to create whole new inventories of much the same junky food, tweaked to address the worry-du-jour, as in: sure, they are cookies- but they are gluten free now! Eat them all!

Third, manufacturers have the option of varying the marketing collateral- the banner ads, the nutrient claims- even if the products don’t really vary. Sometimes, we wind up with several versions of much the same concoction because the packaging graphics vary; kids’ cereals are a sad example.

When the only foods available to us were actual foods, rather than mostly manufactured concoctions, variety was indeed a good idea. Thousands upon thousands of nutrient compounds are found in vegetables, fruits, grains, nuts, seeds, beans, and legumes. We are a long way from knowing what they all do for us, but we know enough to suspect that many are beneficial in complementary ways. So, yes: a variety of diversely colored, whole plant foods