The Nutritarian

Healthy Eating Insight

What is the GI system?

Written By: The Nutritarian - Jan• 26•12

Quick answer: GI stands for glycemic index and it determines the rate at which a carbohydrate is digested and released into your blood.

Source: In Defense of Food: An Eater’s Manifesto by Michael Pollan, 2008.

GI Ratings: Low (55 and under) Medium (56-69) High (70 and above)

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,,,,

Low-fat yogurt 14

Asparagus 15

Broccoli 15

Cherries 22

Kidney beans 29

Apples 38

Carrots 39

Grapes 46

Oatmeal 49

Whole-grain bread 50

Yams 51

Sweet potato 54

Brown rice 55

Bananas 55

Popcorn 55

Couscous 58

Corn 60

Cheese pizza 60

Ice cream 61

Split pea soup 64

Pineapple 66

Grapenuts 67

Whole wheat bread 69

Watermelon 72

Long-grain rice 75

Rice cakes 77

Pretzels 83

Baked potatoes 78-85 French baguette 95

Dates 103

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.

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