Any diet that contains carbohydrates can be ranked as being either low-, medium-, or high-glycemic, referring to the glycemic index or load. This ranking system would apply to both weight-loss diets and habitual ways of eating.
Specific foods with significant amounts of carbohydrate have been tested for their ability to rapidly raise blood sugar levels as compared to eating pure glucose, a type of sugar. The number generated by the test is the glycemic index (GI) and ranges between 0 and 100.
Here are some GI values from Wikipedia’s entry on glycemic index:
Low GI (55 or less)
- most fruit and vegetables (except potatoes, watermelon), grainy breads [made of or resembling grain?], pasta, legumes/pulses, milk, products extremely low in carbohydrates (fish, eggs, meat, nuts, oils), brown rice
Medium GI (56 – 69)
- whole wheat products, basmati rice, orange, sweet potato, table sugar, most white rices (eg, jasmine),
High GI (70 and above)
- corn flakes, baked potato, watermelon, croissant, white bread, extruded cereals (eg, Rice Krispies), straight glucose (100)
Low-GI diets encourage the low-GI foods. High-GI diets favor the high-GI foods. Well, duh!
The Human Nutrition Unit at the University of Sydney (Australia) maintains a free online database of glycemic index values of various foods. For example, the GI of Doritos is 42 (corn chips, plain, salted, 1998).