Jane Says: All Carbohydrates Are Not Created Equal
“What are some healthy choices when craving carbs?”
—”Healthy ways healthy days”
People have been obsessed with carbohydrates ever since the 1992 publication of Dr. Atkins’ New Diet Revolution—the runaway bestseller sold more than 15 million copies in the decade—and A Week in the Zone, by Dr. Barry Sears, which followed in 1995. Since then, umpteen other proprietary low-carb diet plans (ka-ching, ka-ching), not to mention conflicting scientific studies, have followed. It’s no wonder that almost 20 years later, many Americans remain confused about which, if any, carbohydrate-rich foods they should be eating.
So, here’s the deal: All carbohydrates are not created equal. The easily digested carbs from the refined white flour in breads, pastries and other sweets, as well as sugary drinks and other highly processed foods have certainly contributed to America’s rapidly spreading waistline and related health problems. But many obesity and public-heath experts think that excess calories from any source is the bigger problem: Americans simply consume more calories (and more frequently throughout the day) and exercise less.
After all, like protein and fat, carbohydrates are a macronutrient—that is, a nutrient that provides calories or energy. Carbs provide the essential vitamins, minerals, fiber, and phytonutrients we all need to maintain body functions and fuel physical activities, from a daily run or chasing after the kids to sitting at a computer and contemplating three measly paragraphs.
I’ll get to some tips on choosing healthy carbs in a minute, but first, some basic science. Carbs are one or more sugar molecules (saccharides) bound together. Single sugars (monosaccharides) include fructose (from fruit) and glucose (from plants, and our bodies’ primary energy source). Two linked sugars (disaccharides) include lactose (from milk) and sucrose (called table sugar when commercially processed from sugar cane or sugar beets). Monosaccharides and disaccharides are so-called “simple” carbohydrates. Small and, well, simple, they’re easy to digest and enter the bloodstream quickly. A “complex” carbohydrate such as starch (which plants use to store energy), on the other hand, consists of long, branching chains of sugars (polysaccharides). Our digestive enzymes break down starch into smaller and smaller chains and, eventually, single glucose molecules. Complex carbs take longer to digest than simple carbs.
Once glucose crosses from the intestinal tract into the bloodstream, the level of blood glucose (aka blood sugar) increases. The pancreas then secretes the hormone insulin to transport the glucose out of the blood to where it’s needed—your muscles and brain. What helps keep blood sugar levels in check (and hunger at bay) is fiber, which is what gives plants physical structure and strength, and which can’t be broken down into glucose molecules. If you want to read more about how fiber keeps your body in good working order and helps prevent disease, the Harvard School of Public Health has you covered.
Foods that contain carbohydrates can be ranked according to how easily glucose is absorbed from them in a system called the Glycemic Index (GI). In general, highly processed foods have a higher glycemic index than unprocessed foods do, but as NYU nutrition professor Marion Nestle points out in What to Eat: An Aisle-by-Aisle Guide to Savvy Food Choices and Good Eating, there are many exceptions. “Carrots have sugars ... and these are rapidly absorbed. But the total amount of sugars in carrots is so small—less than 5 grams (a teaspoon) in one large carrot—that their rapid absorption hardly matters. You would need to eat at least ten carrots to ... raise your blood sugar appreciably.” Even though the Glycemic Index of carrots may be high, she notes, their Glycemic Load (GL), which takes the quantity of food (thus calories) into account, is low, and that’s really more to the point.
Nestle doesn’t take much stock in published lists of GI and GL values. “The numbers vary depending on who is doing the measuring and how it is done, and they change drastically when you eat more than one food at a time (which, of course, is the typical situation),” she writes. A number of other variables that affect GI include a snack or earlier meal (GI is based on blood-sugar levels after fasting); fat, fiber, or acid content; and degree of ripeness.
That is way too complicated for me. Like Nestle, I think GI/GL values serve as a helpful reminder to avoid heavily processed foods, especially those made with refined white flour, as well as foods high in added sugars. A more realistic way of incorporating healthy carbs into your diet, though, is to simply enjoy a wide range of unprocessed foods. If weight loss is your concern, focus on portion size, how often you eat during the day, and getting more exercise. Personally, I’m thinking about one of those treadmill-desks.
Tips on choosing healthy carbs
Work whole grains such as barley, oats, wheat berries, or farro into your diet. They’re low in fat and contain vitamins, minerals, and all-important fiber. Swap out white bread and rice for whole-grain breads and brown rice. If you absolutely cannot give up your favorite pasta brand, eat it less often, mix it with a whole-wheat pasta, or serve it with a fiber-rich vegetable like broccoli.
The complex carbs in legumes come packaged with protein and other nutrients. If your family is legume-phobic, ease them along with hummus (which is made from chickpeas) and crudités as a snack, or include pinto or black beans on taco night (and serve corn tortillas instead of flour ones). Organic edamame (green soybeans), cooked in the pod and served with a scattering of flaky sea salt or a dipping sauce, are easy to love, and just one-half cup has 12 grams of carbohydrates and 3 grams of fiber—not to mention 11 grams of protein.
Many people don’t realize that vegetables and fruits are a terrific source of quality carbs. Those especially high in fiber include avocados, broccoli, sweet potatoes, spinach and other greens, berries, melons, citrus fruits, bananas, pears, and apples. And even though regular potatoes are much maligned for their high GI value, they’re a rich source of vitamins (including vitamin C), minerals (calcium, iron, phosphorus, potassium), and protein. Dairy products, too, are a significant source of healthy carbs, but I’m talking yogurt and milk, here, not an ice cream sundae.