Foods with a low glycemic index, including steel cut oats, cause fewer spikes in blood sugar than foods with a higher glycemic index, such as white bread. However, even when using the glycemic index of a food, the diabetic should consider its overall nutritional value and use portion control.
A carbohydrate with a glycemic index below 55 is low. Carbohydrates such as beans, whole grain foods and nonstarchy vegetables also have a low glycemic index. Most fruits are safe. While sweet potatoes and carrots are a starchy vegetable, their glycemic index is low enough that they do not cause a spike in blood sugar.
Carbohydrates with a glycemic index above 79 are high and more likely to cause spikes in blood sugar levels. Melons, pineapples, white potatoes, sugary desserts and flour containing products all have high glycemic indexes. Cooked and processed foods have an increased glycemic index.
While diabetics should keep glycemic index in mind when choosing foods, the American Diabetes Association indicates most diabetics do better with carbohydrate counting than relying on glycemic index alone. The amount of carbohydrates in the food helps the diabetic to maintain his blood sugar in a healthy range, while glycemic index is helpful in preventing spikes and drops in blood sugar levels.