What is the GI System?
GI stands for glycemic index and it determines the rate at which a carbohydrate is digested and released into your blood.
GI Ratings: Low (55 and under) Medium (56-69) High (70 and above)
Source: In Defense of Food: An Eater’s Manifesto by Michael Pollan, 2008.
The glycemic index of food rates carbohydrate’s effect on blood sugar. Low GIs causes small fluctuations, which help maintain energy throughout the day. High GIs cause a spike and crash, which correlates to energy. Sources: Glucose Revolution, Glycemicindex.com, Nutritiondata.com, southbeachdietplan.com, diabetesnet.com
Low-fat yogurt 14
Kidney beans 29
Whole-grain bread 50
Sweet potato 54
Brown rice 55
Cheese pizza 60
Ice cream 61
Split pea soup 64
Whole wheat bread 69
Long-grain rice 75
Rice cakes 77
Baked potatoes 78-85 French baguette 95
White rice 110
Factors That Affect the GI System
Source: Good Carb, Better Carb Cookbook by Cathy Leman R.D. and Linda R. Yoakam, M.S., R.D., L.D., 2004.
- Degree of ripeness. The riper it gets, the higher the sugar content and GI level.
- Acids in foods slow the rate at which your body digests.
- Every person digests carbs differently.
- GI increases with cooking time. The cooking process makes starch and a molecule swell, softening food and making it faster to digest.
- If a food is eaten with a combination of carbs, protein, and fat the carb will have a lower GI than it would alone because the fat and protein slow down its digestion.
- Portion size will affect the GI since GI is calculated based on nine times a food’s typical serving size. Glycemic load, or GL calculations were created to give a rating based on portion size. Using watermelon, a food with a GI of 72 is multiplied by the available carb (5.75) and then divided by 100 to get a GL of 4. It is important not to dismiss high GI foods. A small portion of watermelon or any nutritious food that appears to have a high GI will still provide lots of vitamins, minerals, fiber and a low GI when eaten in smaller portions.