Carbs: To eat or not to eat?: With the inevitable ebb and flow in the popularity of macronutrients, the average consumer is in a quandary as to whether he should consume carbs or not, and if there is really some credence to the gluten-free (no wheat, rye, oats and barley), mania that appears to have gripped the nation. In the 90’s when fats were demonized, carbohydrates were elevated to stardom with popular diet programs like Jenny Craig creating meals with at least 60% of their calories from carbohydrates.
However in the 2000’s, as consumers started flocking to gluten-free products, carbs may have fallen out of favor again as evidenced by data on the CDC website that showed statistically significant macronutrient trends : average carbohydrate intake decreased, and average protein intake increased between 1999-2000 and 07-08.(1)
Let’s review the facts on carbs and separate them from the flim flam that often sadly surrounds the topic of nutrition today. First off, let’s start with a brief review of the functions of carbohydrates.
- Fuel source: Carbs are to your body what fuel is for your car. Neither can run without a primary energy source. However choose “premium” over “regular” every time if you wish to get the most mileage out of your body, just like high quality premium grade gasoline, and try not to “overfill”.
What are premium carbs? Whole and unprocessed carbohydrates from whole grains, legumes, fresh fruits and vegetables, would be considered premium carbs. Whole grains are intact grains. After processing, they should retain the same proportion of bran, germ, and endosperm as that of the original grain to be considered whole grains (2)(3). Intact whole grains have an outer bran layer that is rich in insoluble fiber, and the inner germ layer packs a concentrated source of nutrients such as Vitamin E, phytonutrients and minerals to supply food for the growing sprout. Whole grains are significantly higher in dietary fiber, containing about 80 % more dietary fiber than refined grains (3).
Unfortunately, today’s grains are pulverized in a mill that strips the fiber and nutrient rich bran as well as the germ, leaving behind the starchy endosperm and a super fine white flour. This creates a greater surface area for your digestive enzymes to work on, leading to rapid breakdown of the available carbohydrate to sugar or glucose, your body’s primary energy currency, a subsequent large release of insulin from the pancreas, followed by a sugar “crash”, prompting hunger pangs later.
Even though many grains are “enriched” by adding back several B vitamins (thiamin, riboflavin, niacin, folic acid) and iron, a key component, fiber is not added back to enriched grains. Thus, you could say that today we are eating the pale shadow of the hearty, wholesome grain that our ancestors ate.
It is these refined grains that have given carbs a bad rap. In our quest to avoid the undesirable carbs, some of us may have mistakenly shunned the healthful whole grains that are high in fiber, and virtually thrown out the baby with the bath water! The take away here is that the quality of carbs is key, just as the quality of fats counts as we saw on the previous posts on dietary fats.
Despite the current dietary guidelines recommending that individuals consume at least one-half of all their grains as whole grains (i.e. 3 servings/day; 1 serving = 16 g), (4), dietary intake data indicates that the average whole grain intake is 1 serving/day, with the majority of Americans not meeting their whole grain daily intake recommendations (5, 6).
2. Protein sparing action of carbs
The “protein sparing” effect of carbs implies that when carbs are consumed in adequate amounts, it enables the body to use protein for what it’s meant to be used- i.e as building blocks and to help repair and re-build cells, rather than for energy. Only adequate dietary carbs (and to a lesser extent, dietary fat), can prevent the use of protein for energy, and it’s action in doing so is called the “protein sparing” effect of carbs. To ensure complete sparing of body protein and avoidance of ketosis requires 50-100 grams of carbs per day depending upon the individual. On extreme low carb diets, large amounts of protein have to be consumed to ensure that body protein is not sacrificed for energy.
3. Source of fiber:
Fiber is the structural part of the plant and is derived exclusively from carbohydrate rich foods such as whole grains, legumes, fruits, vegetables and nuts. Although fiber is the part of the plant food that you cannot digest, it is ironically just as important as the part that you can.
Ever notice that a bowl of oatmeal with some fruit seems to hold you longer than a giant bagel? The higher fiber content in this meal simply means that your body has to work harder at breaking down the carbs in those foods, causing a slower rise in sugar, less insulin from your pancreas, preventing hunger pangs later. The refining process however strips the bagel of fiber, thus enabling your body to digest and absorb the carbs rapidly, leading to spikes in sugar, insulin, a subsequent sugar crash, setting off the all too familiar “snack-attack”.
There are numerous studies demonstrating the health benefits of fiber and whole grains. Epidemiological and clinical studies demonstrate that intake of dietary fiber and whole grain is inversely related to obesity, type two diabetes, possibly cancer and cardiovascular disease. (6),(7),(8),(9)
Now that we understand the benefits that whole grains and “premium” carbs bring to the table, let’s look at what it takes to actually get these products to our dining table, literally! Please read my next post: “Whole grains and fiber:Unraveling the puzzle”, to learn more.
Disclaimer: This blog is strictly for informational purposes and should not be construed as medical advice. Please consult your Doctor or Registered Dietitian for recommendations tailored for your specific needs.