When It Comes to Carbs, Don't Be Dense

As the obesity and diabetes epidemics progress, the search for causes and explanations becomes ever more urgent.  Why, now, are so many people struggling with these diseases? There are many theories…  I recently came across one interesting idea that appeals to my sense of possibilities, and it came from a 2012 paper entitled, "Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity." Quite a mouthful. But author Ian Spreadbury makes a pretty simple and interesting point in this paper. The notion is that ancestral foods, (foods that humans have been eating for thousands of years), are not particularly dense with digestible carbohydrates, but many modern foods are.

Maybe our body’s mechanism for managing carbohydrate calories is gradually overwhelmed by our modern low-fat diet, rich with foods that are very dense with carbohydrate calories. Could these modern foods be driving the twin obesity and diabetes epidemics? The low-fat diet, introduced and encouraged by our government in the late 70’s and early 80’s, pushed us away from some traditional foods (they asked us to decrease consumption of  meat, animal fats, full-fat dairy, and eggs) and toward modern foods (they asked us to increase consumption of grains like bread, cereal, and pasta). And, since that is when these epidemics picked up speed, it seems like a point in time that deserves some scrutiny.

Calculating the carbohydrate density of a food is simple. In a 100 gram serving, take a look at the grams of total carbohydrate and simply subtract the grams of fiber.  Like so:

Although the author provides his own nifty graph in Figure 1 of his paper (scroll down a bit), let me offer a more colorful version of the carbohydrate density of various modern and ancestral foods. Note that the scale (0-100g) is the same in these two graphs...  You will see that there is very little overlap. With the exception of cassava, taro, and plantains, ancestral foods are all less dense (from a carbohydrate perspective) than the modern creations listed.

Are there modern creations that I left out that are lower in carbohydrate density? Yes. I cheated a little to make the graphs look better. For example, the mysterious creation, Kraft Free Singles (fake, fat-free cheese), has a carbohydrate density of only 11.5. Although low, this is more than triple the carbohydrate density of real cheddar cheese (3.1), so the pattern of higher carbohydrate density in modern foods is intact. Likewise, low-fat fruit yogurt scores 19.1 -- again, lower than most modern creations, but quadruple the carbohydrate density of plain full-fat yogurt (4.7).

Of course, one of the reasons most of these modern foods score so high on this scale is that they are not a real, whole food full of fiber and/or water. So, might it help to drink a lot of water when chowing down on that granola bar? Maybe... it certainly could not hurt. Note, also, that it definitely does NOT help to wash the granola bar down with soda or Gatorade or Snapple or Red Bull or apple juice.  Nor does it help to add a big glass of fresh-squeezed orange juice to your breakfast of Post Honeycomb cereal. VERY BAD IDEA. That would add to your body's carbohydrate load, now wouldn't it?

Whole Grains - Do We Need Them?

No.

(Hmmm... Stop there or elaborate a little?)

People have been eating grains for thousands of years. But, before that, people thrived for hundreds of thousands of years without grains. And, there are (and were) many traditional societies whose diets are (and were) completely grain free. So, it would seem that, no, a healthy diet does not NEED to contain grains.

But what about nutrients? Aren't grains a wonderful source of vitamins and minerals? Not really. On a per-calorie basis, when you compare grains to an equal serving of non-starchy veggies, the vegetables are a much better source of nutrients. Check out this chart from Jonathan Bailor's blog. Even vitamin enriched whole wheat flour pales in comparison to veggies.

But what about fiber? Although whole grain products have twice as much fiber as, say, a doughnut or Wonder Bread, they don't measure up to non-starchy veggies. A serving of veggies with equivalent calories has seven times the fiber of whole grains. So if you want fiber, load up on veggies (with butter, of course)!

And, if you like skeptical musings, you might enjoy this post, entitled 'Fun with Fiber: The Real Scoop' from Mark Sisson's blog, questioning the very notion that fiber is important in a healthy diet.

Whole grains. Traditionally, that meant the whole grain. As in, the whole kernel. Think: pearled barley, wheat berries, steel cut oats, farro.  Grains were soaked, boiled, fermented (like beer), and sprouted. These are the whole grains that have been consumed for thousands of years. Modern eaters tend to turn to whole grain flour. Let's look at the difference, from the perspective of the glycemic index (GI) -- a measure of how quickly those grains turn into glucose in our blood:

• White Bread 73 GI

• Whole Wheat Bread 71 GI

• Coco Pops 77 GI

• Grape Nuts 75 GI

• Special K 69 GI

VERSUS

• Wheat Berries 30 GI

• Pearled Barley 28 GI

As you can see, when whole grains are pulverized into flour for breads or cereals, they lose all of that 'whole grain goodness', at least from a blood sugar perspective, and perform very much like white flour. But who wants to eat wheat berries for breakfast? (Maybe porridge? That's vintage.) The reality is that our love affair with grains is almost entirely a love affair with highly processed food - the breads, cereals, crackers, chips, pastas, and pizza crusts made with flour.

So why do we keep hearing so much about “heart-healthy whole grains”? Observational studies. That’s right. Almost all of the science that looks at the benefits of whole grains is based on weak associations (and imprecise food frequency questionnaires). With any epidemiological study, the “healthy user bias” creeps in… after all, who eats whole grains other than health-minded people who have many healthy habits that improve their outcomes? So if you read a headline about whole grains, check to see if the reported result is an actual experimental result or just an unreliable observational association.

Bottom line -- whole grains are a great source of CALORIES. And whole grain flour is a great source of the kind of calories that spike your blood sugar. So, if you need more of that, go for it!