"If you're hungry two hours after a meal, you're eating the wrong foods."

Susan B. Roberts, Department of Agriculture's                                                           

Human Nutrition Research Center on Aging,

Tufts University, Boston

Today's active lifestyles demand effective use of the energy we consume in foods. Carbohydrates, a principal source of energy in the diet, significantly impact our energy levels throughout the day. Upon digestion, most carbohydrates become blood sugar, which then is available as energy for the body. Matching the available energy (blood sugar) to physiological demand is a relatively new quantitative measurement of energy. (The typical measurement is calories or joules). Managing blood sugar levels can assist in managing energy levels.

Rapidly digestible carbohydrates, such as sugars and most processed carbohydrates deliver energy that is rapidly absorbed by the body. These types of carbohydrates are high glycemic because they deliver a fast and high peak of blood sugar. However, the higher peaks of blood sugar result in lower crashes of blood sugar. This is due to the insulin secreted by the body to stimulate transport of this sugar into the cells and out of the blood.

Individuals experiencing low blood glucose may feel sluggish, drowsy, and less alert. In other words, they are experiencing a lack of energy. Moderating (or minimizing) these spike-and-crash fluctuations in blood sugar results in better energy management. More moderate peaks may not result in below-baseline crashes because they don’t stimulate the production of high levels of insulin. It should be noted that there is great variation in individual responses: some people are more sensitive to changes in blood sugar levels while others are less affected. Genetic variations and health conditions greatly influence the body’s management of glucose.

Rapidly digested carbohydrates are required under some circumstances. Athletes require rapidly digestible carbohydrates to enable recovery from strenuous exercise and diabetics require rapid energy to recover from low blood sugar. However, continual consumption of rapidly digested carbohydrates by the general population will result in energy swings.

Slowly digestible carbohydrates, such as whole grains, most unprocessed foods and resistant starches, deliver energy that is released more slowly, providing moderate rises in the body's blood sugar levels. This avoids the low energy crashes and maintains greater energy control throughout the day. However, adding unprocessed whole grains into refined foods significantly changes the taste and texture of these foods, and is not well accepted by consumers.

Resistant starch assists in moderating the body's blood glucose levels while maintaining the organoleptic properties of refined foods. Foods containing resistant starch have a lower glycemic response than other carbohydrate-rich processed foods, making it an ideal ingredient for individuals concerned about maintaining steady blood glucose levels for energy management. Substituting resistant starch for flour in food manufacturing is an easy way to reduce the glycemic load of foods. Numerous clinical trials have demonstrated that food containing resistant starch is low glycemic and low insulinemic. For instance, white bread containing 20% resistant starch produced a glycemic response that was 45% lower than a control white bread containing all rapidly digested carbohydrates.

Additional information on this benefit can be found under "Blood Sugar Response".

The Stats

The 2005 Dietary Guidelines recommend three servings per day of whole grains, but Americans, on average, eat less than one¹

The Guidelines also recommend we eat 8-10 servings of fruits and vegetables per day, but 76.7% of Americans eat 4 servings or fewer daily

The Institute of Medicine has set 130 grams as the daily minimum for carbohydrate consumption, based on the glucose needs of the brain

The Role of Resistant Starch

Eating natural resistant starch, a form of fiber which minimally impacts food flavor and texture, is important for energy management.  It helps to moderate the rapid rise in blood glucose resulting from consumption of processed carbohydrates.  Rapid change in glycemic impact is commonly experienced as fluctuation in energy, particularly as people age.   

The Positive Effects

Eating foods with natural resistant starch helps balance your energy in the hours following a meal, mitigating a drop in blood sugar because:

• It releases part of its energy in the small intestine as glucose and part of its energy in the large intestine as fermentation by-products, such as acetate.  While glucose is the exclusive energy source for the brain, acetate is used as an energy source in muscle and fat tissue.
• It has a lower glycemic and insulin response than the flour it replaces.

1.  The Whole Grains Council, www.wholegrainscouncil.org.

2.  Centers for Disease Control and Prevention “5 a Day” program.

3.  Institute of Medicine