Carbohydrates: Looking through a New Lens

The popularity of the low carb diet was superseded almost a decade ago by the emergence of the Mediterranean eating pattern. Nevertheless many people continue to fearful about eating this necessary nutrient group and express interest in knowing a bit more about them.  This blog article is intended to be a relatively quick and easy read to add to your existing bank of nutrition knowledge.

Carbohydrates serve many roles in the human body; however, the primarily role is supplying a steady source of fuel. Consuming too many carbohydrates to meet energy requirements, or choosing a poor quality carbohydrate such as white bread or sugar cookies, or consuming rapidly digesting carbohydrates such as a large glass of orange juice can set the stage for chronic health problems, food cravings, low energy, low moods, poor sleep and ….yes, weight gain.

Carbohydrates are the sugars, starches and fibers. They are generally thought of in terms of “simple” or “complex”. It was thought that a simple carbohydrate (one or two sugar molecules of sugar) would cause a more rapid spike in blood sugar than a complex carbohydrate (many sugar molecules linked together) that took slightly longer to digest. However, this way of looking at carbohydrates, as either simple or complex, provides a rather incomplete and outdated picture.

Glycemic Index and Glycemic Load: A better understanding of carbohydrates is through the lens of the glycemic index (GI) and more recently the glycemic load (GL) scale.

Glycemic index graph shows how rapidly a carbohydrate converts to blood glucose.The glycemic index is a useful gauge of how rapidly a carbohydrate converts to blood glucose and therefore how rapidly it causes the detrimental blood glucose spikes. However, there are a few problems with this system because it does not take into account the actual amount of carbohydrate in a typical serving size. For example, carrots rate highly on the glycemic index, but an actual serving size of carrots contains very little carbohydrate and would not adversely affect blood glucose. Using the newer glycemic load scale, a typical ½ cup serving size of carrots would rate a “2” which is quite low on the scale and indicates that it would have little impact on blood glucose.

The glycemic load scale is a realistic and a more useful way to view carbohydrates.  For comparison of the two glycemic gauging systems the table below shows and compares values of Glycemic Index (GI) and Glycemic Load (GL) for a few common items.

the table below shows and compares values of Glycemic Index (GI) and Glycemic Load (GL) for a few common items.

For more information on glycemic values go to www.glycemicindex.com

Drawbacks of Glycemic Load – Despite the usefulness of the glycemic load scale there are limitations. For example, food preparation methods, the combination of foods eaten at the same meal (see Nutrition Overview: The Big Picture blog), individual differences to glycemic response, and variations in particular food items all affect the glycemic load.

In general, the more refined and processed a carbohydrate is the more rapidly it converts to sugars which can lead to a host of problems. In a nutshell, for long term good health is it best to avoid processed and highly refined carbohydrates.

If you are interested in learning more about the glycemic load scale and low glycemic eating patterns the following list are excellent resources.

  • The Glycemic Load Diet by Rob Thompson
  • www.health.harvard.edu
  • www.glycemicindex.com
  • www.ajcn.org
  • The Glycemic-Load Diet Cookbook by Rob Thompson & Dana Carpender
  • Low GI diet cookbook Miller, Powell, Price

Fiber: Another important component of carbohydrate is fiber. Fiber is the part of fruits and vegetables that is not digested; it travels through the digestive tract relatively intact. Foods high in fiber travel more slowly through the digestive process than refined carbohydrates and thereby have less impact on blood glucose levels.  Basically, there are two kinds of fiber, soluble and insoluble. Each has benefit and both are important for good health. Fruits, vegetables, nuts, seeds, and whole grains contain good amounts of fiber.  An ideal daily intake is about 40 grams.

Does the Glycemic effect matter? You bet it does………
The glycemic effect or glycemic response, i.e., how fast a food or meal causes blood glucose to rise is really the thrust of we want to modify in terms of a healthy eating pattern and to maintain long term well-being.  When blood glucose remains stable with only gentle rises then all of the metabolic hormones associated with food regulation including cholesterol metabolism remain balanced. This translates to the body’s physiology working with you, rather than against you.

For a more complete understanding about the most practical and easiest way to modify the glycemic effect through a healthy eating pattern without having to refer to a glycemic gauge please see blog:  Nutrition Overview: The Big Picture I think you’ll enjoy reading it.