Low-glycemic diet foods are foods that have low glycemic index scores. The glycemic index measures how fast specific carbohydrates increase your body's blood sugar levels. Low-glycemic diet foods can only measure carbohydrates' effect on blood sugar "because fat causes virtually no blood sugar elevation" and protein causes very little elevation, according to "Dr. Atkins' New Diet Revolution." All meats and other no-carb foods are low-glycemic diet foods.
History
Two kinds of carbohydrates exist--complex and simple. Fibers and starches are complex; sugars are simple. Most nutritionists considered complex carbohydrates healthy low-fat foods until University of Toronto researcher David Jenkins created the glycemic index in 1981. The glycemic index was the first tool to measure a food's effect on blood sugar, and it "shattered long-held assumptions" about starches, according to the Harvard Heart Letter. Nutritionists knew sugars increased blood sugar, but the glycemic index showed that starches often had a greater effect. Fibers have little effect.
Explanation
The glycemic index compared specific carbohydrates' effect on blood sugar to glucose's effect. Jenkins gave glucose a score of 100. A food with a 50 score increases your body's blood sugar levels half as fast as glucose. Foods are low- glycemic foods if their score is 55 or lower, high-glycemic foods if their score is 70 or higher, according to the Harvard School of Public Health. Today, there are many glycemic indexes with different numbers, but the "relative order" of foods on the lists is consistent, wrote Atkins.
Significance
High blood-sugar levels also have a negative effect on insulin,. "Soothing out your blood sugar and insulin levels help keep your heart in good shape" and help control type 2 diabetes, according to the Harvard Heart Letter. The question is whether lower blood sugar levels are the key to losing weight. The Harvard Heart Letter said it "may," but the Atkins Diet and the South Beach Diet are based on the premise that high-glycemic foods are the cause of body fat and fatty foods do not cause weight gain.
Changes
The concept of low-glycemic diet foods has persuaded many people to eat more fiber-rich and fewer starch-rich foods. Fiber-rich foods have low glycemic index scores because you take longer to digest them. Soy beans have an 18 score, according to the Harvard Heart Letter's list. Starch-rich foods have high scores because they are digested rapidly. Baked potatoes have an 85 score. All-Bran, with a 42 score, is the only low-glycemic cereal. Pumpernickel, 50, is the bread with the lowest glycemic score.
Good Carbs
Many high-carb beans, nuts, fruits and vegetables are low-glycemic diet foods because they are high-fiber foods. Those with a score below 30 include chickpeas, kidney beans, lentils, cashews, peanuts, grapefruit and prunes, the Harvard Heart Letter reports. Vegetables with a score below 20 include spinach, beets, eggplant, cucumbers, celery, cabbage, Brussels sprouts, broccoli and asparagus, "The South Beach Diet" reports. In addition, pasta cooked for a short time leaves its starch so "closely packed together" that some of it doesn't reach your blood and is a low-glycemic food, Atkins wrote.
References
- The South Beach Diet"; Dr. Arthur Agatston; 2003
- "Dr. Atkins' New Diet Revolution"; Dr. Robert Atkins; 2002
- Harvard School of Public Health: Carbohydrates: Good Carbs Guide the Way
- Harvard Heart Letter: Carbohydrates and Health: Not That Simple...Or That Complex
