GI - The Glycemic Index

Everyone loves to tell you all about low GI foods, because it slowly releases energy, "it'll last longer". Which is in fact true, it does release it slowly, but what exactly does it mean, and is it always good to eat low GI foods..? Do you know which foods are low GI..? While reading the article, try thinking about foods that you know as low GI, and I will include a list at the end.

The glycemic index is used to classify foods in terms of how long they raise the blood glucose levels. The reference point on the GI scale is white bread, which has a reading of 100 on the glycemic index. Foods that have a high GI are digested quickly, they raise blood glucose rapidly and also stimulate high insulin levels (insulin aids in transporting glucose from the blood to the muscle). The exact opposite is true for lower GI foods.

Now contrary to popular belief, sugars do not always rank as higher on the scale when compared to starches. Potatoes and table rice, rank higher than normal table sugar (sucrose) also, many things can affect the GI of a particular food (cooked/uncooked, processing, is it part of a meal or a snack on its own etc…?). So although the GI of a food is important, it is not a perfect way of analyzing your diet.

Studies have been shown that low GI foods increase exercise performance (Demarco et al.) but other studies have shown no difference between eating low/high GI foods before exercise/competition (Wee et al) (Thomas et al). So if your interest is when to eat certain foods before/after/during events, try experimenting a bit as more research needs to be done on the glycemic index with regards to exercise performance.

Glycemic index of certain foods:

White Bread 99
Sponge Cake 66
Corn Flakes 116
Oats 78
White Rice 91
Brown Rice 79
Linguine (pasta) 70
Milk (full cream) 38
Honey 78
Sucrose (sugar) 97
Apple 57
Banana 74
Orange 60
Potato (baked) 121
Peanuts 21
Yoghurt (sweetener) 20

(Baechle TR, Earle RW, essentials of strength training and conditioning, 2008)

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