What is glycaemic index (GI)

The glycemic index is a value assigned to foods based on how slowly or how quickly those foods cause increases in blood glucose levels. Also known as "blood sugar," blood glucose levels above normal are toxic and can cause blindness, kidney failure, or increase cardiovascular risk. Foods low on the glycemic index (GI) scale tend to release glucose slowly and steadily. Foods high on the glycemic index release glucose rapidly. Low GI foods tend to foster weight loss, while foods high on the GI scale help with energy recovery after exercise, or to offset hypo- (or insufficient) glycemia. Long-distance runners would tend to favor foods high on the glycemic index, while people with pre- or full-blown diabetes would need to concentrate on low GI foods. Why? People with type 1 diabetes and even some with type 2 can't produce sufficient quantities of insulin—which helps process blood sugar which means they are likely to have an excess of blood glucose. The slow and steady release of glucose in low-glycemic foods is helpful in keeping blood glucose under control.

There are three ratings for GI:

Low = GI value 55 or less

Medium = GI value of 56 – 69 inclusive

High = GI 70 or more

So why do we need good quality Low GI carbohydrates?

You need carbs as they break down into glucose in your body providing the:

• main fuel for our brains and nervous systems,
• preferred source of fuel for most organs and our muscles during exercise.

Consuming good quality carbohydrates with Low GI ones help to facilitate the management of diabetes, weight loss management and reducing the risk of developing type 2 diabetes, diabetes complications and other chronic lifestyle diseases. In fact a low GI diet provides health benefits for everybody across all stages of life.

But the glycemic index of foods tells only part of the story. What it doesn't tell you is how high your blood sugar could go when you actually eat the food, which is partly determined by how much carbohydrate is in an individual serving. To understand a food's complete effect on blood sugar, you need to know both how quickly the food makes glucose enter the bloodstream, and how much glucose it will deliver. A separate value called glycemic load does that. It gives a more accurate picture of a food's real-life impact on blood sugar. The glycemic load is determined by multiplying the grams of a carbohydrate in a serving by the glycemic index, then dividing by 100. A glycemic load of 10 or below is considered low; 20 or above is considered high. Watermelon, for example, has a high glycemic index (80). But a serving of watermelon has so little carbohydrate (6 grams) that its glycemic load is only 5.

To help you understand how the foods you are eating might impact your blood glucose level, here is an abbreviated chart of the glycemic index and glycemic load, per serving, for more than 100 common foods. A more complete glycemix index chart can be found in the link below.

FOOD	Glycemic index (glucose = 100)	Serving size (grams)	Glycemic load per serving
BAKERY PRODUCTS AND BREAD
Banana cake, made with sugar	47	60	14
Banana cake, made without sugar	55	60	12
Sponge cake, plain	46	63	17
Waffles	76	35	10
Bagel	72	70	25
Baguette	95	30	14
Coarse barley bread, 80% kernels	34	30	7
Hamburger bun	61	30	9
Pumpernickel bread	56	30	7
50% cracked wheat kernel bread	58	30	12
White wheat flour bread	75	30	11
Whole wheat bread, average	69	30	9
100% Whole Grain bread	51	30	7
Pita bread, white	68	30	10
Corn tortilla	52	50	12
Wheat tortilla	30	50	8
BEVERAGES
Coca	63	250 mL	16
Fanta	68	250 mL	23
Apple juice, unsweetened	41	250 mL	12
Cranberry juice cocktail	68	250 mL	24
Orange juice, unsweetened	50	250 mL	12
Tomato juice	38	250 mL	4
BREAKFAST CEREALS AND RELATED PRODUCTS
Cornflakes	81	30	20
Muesli	56	30	10
Oatmeal	55	250	13
Instant oatmeal	79	250	21
GRAINS
Pearled barley	25	150	11
Couscous	65	150	9
Quinoa	53	150	13
White rice	72	150	29
Brown rice	50	150	16
Whole wheat kernels	45	50	15
Bulgur	47	150	12
COOKIES AND CRACKERS
Crackers	74	25	13
Vanilla wafers	77	25	14
Shortbread	64	25	10
Rice cakes	82	25	17
Rye crisps	64	25	11
Soda crackers	74	25	12
DAIRY PRODUCTS AND ALTERNATIVES
Ice cream, regular	62	50	8
Milk, full-fat	31	250 mL	4
Milk, skim	31	250 mL	4
Reduced-fat yogurt with fruit	33	200	11
FRUITS
Apple	36	120	5
Banana	48	120	11
Dates, dried	42	60	18
Grapefruit	25	120	3
Grapes, black	59	120	11
Oranges, raw	45	120	5
Peach	42	120	5
Peach, canned in light syrup	52	120	9
Pear, raw	38	120	4
Pear, canned in pear juice	44	120	5
Prunes, pitted	29	60	10
Raisins	64	60	28
Watermelon	72	120	4
BEANS AND NUTS
Baked beans	40	150	6
Black-eyed peas	50	150	15
Black beans	30	150	7
Kidney beans	34	150	9
Lentils	28	150	5
Soy beans	15	150	1
Cashews, salted	22	50	3
Peanuts	13	50	1
PASTA
Macaroni	50	180	24
Macaroni and Cheese	64	180	33
Spaghetti, white, boiled	46	180	22
SNACK FOODS
Corn chips, plain, salted	42	50	11
Fruit Roll-Ups	99	30	24
M & M's, peanut	33	30	6
Microwave popcorn, plain	65	20	7
Potato chips	56	50	12
Pretzels, oven-baked	83	30	16
Snickers Bar	51	60	18
VEGETABLES
Green peas	54	80	4
Carrots	39	80	2
Parsnips	52	80	4
Baked russet potato	111	150	33
Boiled white potato	82	150	21
Instant mashed potato	87	150	17
Sweet potato	70	150	22
Yam	54	150	20
MISCELLANEOUS
Hummus (chickpea salad dip)	6	30	0
Chicken nuggets, frozen, reheated in microwave oven 5 min	46	100	7
Pizza, plain baked dough, served with parmesan cheese and tomato sauce	80	100	22
Honey	61	25	12