Many people have heard of the glycemic index (GI), but few truly understand what it's all about. A recent study released in August of 2012 showed that eating foods low on the GI scale helped regulate blood sugar over a twelve hour period. Although it has also been proposed that low GI foods help control hunger, this study found no significant difference in satiety and hunger among the high GI and low GI groups.
To use the GI, you must first understand how the rating system works. The GI assigns a number to each food that represents the effects that food will have on your blood sugar. Glucose is given a high score of one hundred which is the highest scored food on the scale. The rate at which any other food breaks down and releases sugar in your blood stream as compared to glucose determines that foods score.
Simple carbohydrates with high sugar and low fiber content are easily broken down by the body and will be high on the GI. It is suggested that foods that are high on the GI scale cause a sharp rise in your blood sugar that is associated with type 2 diabetes and obesity. Examples of foods with a high GI are white bread, white pasta, white rice, cake, waffles, doughnuts, cornflakes, white potatoes and watermelon. All of these foods are low in fiber and have less grams of fat than they do carbohydrates.
Foods that have a higher fiber or fat contact and are not broken down easily by the body tend to have a lower GI score keeping your body more stable. According to the American Diabetes Association, a food is considered to have a low GI if its score is below fifty five. Over the years, researchers have shown that people who eat lower GI foods tend to have less body fat than those that consume high GI foods. Examples of foods low on the GI scale are milk, multigrain breads, yogurt, apples, peaches, grapes, peanuts, tomatoes and almost all green vegetables.
Many diets such as South Beach and Sugar Busters rely on combining low GI foods with high GI foods at every meal to ensure blood sugar does not spike. The idea is that controlling blood sugar will help control overall diet. By practicing a diet filled with low GI foods, patients will have an easier time controlling your blood sugar and lower your chances of developing diabetes. However, remember that even if a food is low on the glycemic index you must practice portion control and watch the overall calorie count to maintain a healthy BMI.
In this randomized crossover trial, 26 overweight or obese adults received four diets in random order (high GI, high carbohydrate [HGI-HC]; high GI, low carbohydrate [HGI-LC]; low GI, high carbohydrate [LGI-HC]; and low GI, low carbohydrate [LGI-LC]). All meals were prepared by a metabolic kitchen. Participants received breakfast, lunch, and dinner over the course of a 12-h day. Primary outcomes were postprandial serum glucose and insulin quantified as area under the curve. Hunger, fullness, and satiety were assessed by visual analog scale.
The results showed that the HGI-LC, LGI-HC, and LGI-LC diets significantly reduced glucose and insulin area under the curve compared with the HGI-HC diet (P < 0.001 for all comparisons). There were no significant differences in ratings of hunger, fullness, or satiety between the different dietary treatments.
From the results it was concluded that, reducing the GI or carbohydrate content of mixed meals reduces postprandial glycemia and insulinemia, and these changes can be sustained over the course of an entire day. However, there were no differences in subjective hunger and satiety ratings between the diets. These results demonstrate that maintaining a low GI or glycemic load diet is an effective method of controlling serum glucose and insulin levels.
Diabetes Care, Aug, 2012