The glycemic index, or GI, provides information about how carbohydrate-containing foods will affect your blood sugar, insulin level and health. Choosing low-glycemic carbohydrates can be beneficial to your health. Foods with a low GI are digested more slowly that those with a high GI. Low GI foods keep hunger at bay longer, help with weight maintenance or loss, and lessen the risk of some chronic diseases.
Health Effects of High GI Foods
High-glycemic foods -- white potatoes, white bread, donuts, French bread, bagels, dried fruit, waffles, honey, most breakfast cereals and table sugar -- cause rapid, sustained spikes in your blood sugar and insulin levels that may lead to type 2 diabetes, according to the Harvard School of Public Health. Juice, soda and other sugary drinks have the same effect, and there is growing evidence that they increase the risk for diabetes by causing inflammation, raising levels of dangerous fats in the blood and causing insulin resistance.
Health Effects of Low GI Foods
Low-glycemic foods -- whole wheat pasta, whole grain breads, barley, lentils, beans, nuts, salads and AllBran cereal -- contain bran and fiber that take longer to convert from starch to glucose during digestion. This prevents the spikes and dips in blood sugar and insulin levels that result from high-glycemic foods, and lowers your risk for type 2 diabetes. Whole-grain foods are also high in the vitamins, minerals, bran and fiber that have been stripped from highly processed high-glycemic foods.
Other Factors
Other factors influence the glycemic index of foods. Foods high in fat are digested more slowly and have a lower glycemic index. However, you should limit foods with saturated fat, such as red meat and full-fat dairy products, and choose foods containing healthy fats instead. Length of cooking time can increase glycemic index: Spaghetti boiled for five minutes has a glycemic index of approximately 38, but if that same spaghetti has been boiled for 20 minutes, the glycemic index goes up to 61, according to Harvard Health Publications.
The Role of Protein
Eating a high-protein food along with low-glycemic carbohydrates can help you to lose or maintain weight. Researchers suspect this combination keeps blood sugar steady and satisfies hunger longer. Dine on whole-grain crisp bread with lean cheese and an orange for breakfast; whole-grain bread with lean meats, vegetables and sliced avocado for lunch; low-fat cheese sticks and cut-up vegetables for a snack; and a chicken stir-fry with vegetables and whole-grain pasta for dinner.
Expert Insight
A breakfast made up of low-glycemic foods helps kids do better in school. Although any breakfast is better than none, the glucose in high-sugar cereal is absorbed and metabolized quickly. For sustained concentration and memory, low-glycemic foods like oatmeal and other whole grains are much better, according to Terrill Bravender, a professor of pediatrics at Duke University. Low glycemic foods are higher in protein and fiber, so they're more likely to sustain a steady blood sugar level until lunchtime.
References
- Harvard School of Public Health: Simple Steps to Preventing Diabetes
- Harvard Health Publications: Glycemic Index and Glycemic Load for 100+ Foods
- MayoClinic.com: Glycemic index diet: Losing Weight with Blood Sugar Control
- Penn Rodebaugh Diabetes Center: Glycemic Index of Foods
- NPR: A Better Breakfast Can Boost a Child's Brainpower
- Drugs.com: More Protein, Fewer Refined Carbs May Keep Weight Off
