Health & Wellbeing

A Comprehensive Guide to the Glycemic Index (GI)

Shai K.

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You might have heard the words “glycemic index” being thrown around, but weren't sure what the whole thing was about. The glycemic index (GI) is a number that is associated with different foods and shows their effect on the glucose levels in the blood (also known as “blood sugar level”). The number represents the total rise in glucose level after eating that food.

A Comprehensive Guide to the Glycemic Index (GI)

How the GI is determined:

The level of “sweetness” of a food doesn’t necessarily give it a low or high GI value- Foods with simple carbohydrates break down faster in the stomach, releasing glucose into the blood more rapidly and therefore have a higher GI value. Foods with complex carbohydrates, which break down slower, will have a lower GI value.

Other factors that affect GI levels:

Dietary fiber, fat, protein, vinegar and amylose starch will lower the GI levels in food. Research shows that consuming a small amount of alcohol shortly before a meal will reduce the GI level of the meal by 15%.

GI classification:

Classification	GI range	Examples
Low GI	55 or less	beans (white, black, pink, kidney, lentil, soy, almond, peanut, walnut, chickpea); small seeds (sunflower, flax, pumpkin, poppy, sesame); most whole intact grains (durum/spelt/kamut wheat, millet, oat, rye, rice, barley); most vegetables, most sweet fruits (peaches, strawberries, mangos); fructose; mushrooms; chili peppers
Medium GI	56-69	Whole wheat or enriched wheat (not-intact), pita bread, basmati rice, unpeeled boiled potato, grape juice, raisins, prunes, pumpernickel bread, cranberry juice, regular ice cream, sucrose, banana
High GI	70 or higher	white bread (only wheat endosperm), most white rice (only rice endosperm), corn flakes, extruded breakfast cereals, glucose, maltose, maltodextrins, potato, pretzels, bagels

Source: Wikipedia.org

Why do we need to know the GI of food?

Diabetics need to know what their glucose levels are, as changes in these levels can have serious effects on their physical and mental state and may even be detrimental to their health. Non-diabetics can use the GI to better regulate their energy levels and improve results when working out. Some people with a thyroid condition need to control their blood sugar levels in order to lose or maintain weight.

High glycemic foods break down fast, providing a quick energy boost, especially after a workout. Low glycemic foods take more time to break down, making them great fuel to have before a workout, as they release energy into the body in a steady rate. These factors can help you prevent hypoglycemia symptoms.

A 1999 research discovered that people who follow a low GI diet over a prolonged period of time reduce the risk of developing coronary heart disease, type 2 diabetes and even age-related muscular degeneration.

Things to be aware of:

The GI index is not perfect – there are many foods that are low-glycemic which are unhealthy (Chocolate cake – GI 31, ice cream – GI 37) and ones that are high-glycemic that are good for you (Potato/rice – 100 GI). Remember to practice moderation.

The amount of carbohydrates in food can have more of an impact than GI on the glucose levels in your blood. Losing weight and consuming less carbs will also lower blood glucose levels.

The Rise of Blood Sugar Levels After a Meal

A Comprehensive Guide to the Glycemic Index (GI)

Source: Wikipedia.org

The Harvard Medical School recently published a glycemic index of common foods:

FOOD	GI (glucose = 100)	Serving size (grams)	Glycemic load per serving
BAKERY PRODUCTS AND BREADS
Banana cake, made with sugar	47	60	14
Banana cake, made without sugar	55	60	12
Sponge cake, plain	46	63	17
Vanilla cake made from packet mix with vanilla frosting (Betty Crocker)	42	111	24
Apple, made with sugar	44	60	13
Apple, made without sugar	48	60	9
Waffles, Aunt Jemima (Quaker Oats)	76	35	10
Bagel, white, frozen	72	70	25
Baguette, white, plain	95	30	15
Coarse barley bread, 75-80% kernels	34	30	7
Hamburger bun	61	30	9
Kaiser roll	73	30	12
Pumpernickel bread	56	30	7
50% cracked wheat kernel bread	58	30	12
White wheat flour bread	71	30	10
Wonder™ bread	73	30	10
Whole wheat bread	71	30	9
100% Whole Grain™ bread (Natural Ovens)	51	30	7
Pita bread, white	68	30	10
Corn tortilla	52	50	12
Wheat tortilla	30	50	8
BEVERAGES
Coca Cola®	63	250 mL	16
Fanta®, orange soft drink	68	250 mL	23
Lucozade®, original (sparkling glucose drink)	95±10	250 mL	40
Apple juice, unsweetened	44	250 mL	30
Cranberry juice cocktail (Ocean Spray®)	68	250 mL	24
Gatorade	78	250 mL	12
Orange juice, unsweetened	50	250 mL	12
Tomato juice, canned	38	250 mL	4
BREAKFAST CEREALS AND RELATED PRODUCTS
All-Bran™	55	30	12
Coco Pops™	77	30	20
Cornflakes™	93	30	23
Cream of Wheat™ (Nabisco)	66	250	17
Cream of Wheat™, Instant (Nabisco)	74	250	22
Grapenuts™	75	30	16
Muesli	66	30	16
Oatmeal	55	250	13
Instant oatmeal	83	250	30
Puffed wheat	80	30	17
Raisin Bran™ (Kellogg's)	61	30	12
Special K™ (Kellogg's)	69	30	14
GRAINS
Pearled barley	28	150	12
Sweet corn on the cob	60	150	20
Couscous	65	150	9
Quinoa	53	150	13
White rice	89	150	43
Quick cooking white basmati	67	150	28
Brown rice	50	150	16
Converted, white rice (Uncle Ben's®)	38	150	14
Whole wheat kernels	30	50	11
Bulgur	48	150	12
COOKIES AND CRACKERS
Graham crackers	74	25	14
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	57	50	6
Ice cream, premium	38	50	3
Milk, full fat	41	250mL	5
Milk, skim	32	250 mL	4
Reduced-fat yogurt with fruit	33	200	11
FRUITS
Apple	39	120	6
Banana, ripe	62	120	16
Dates, dried	42	60	18
Grapefruit	25	120	3
Grapes	59	120	11
Orange	40	120	4
Peach	42	120	5
Peach, canned in light syrup	40	120	5
Pear	38	120	4
Pear, canned in pear juice	43	120	5
Prunes, pitted	29	60	10
Raisins	64	60	28
Watermelon	72	120	4
BEANS AND NUTS
Baked beans	40	150	6
Blackeye peas	33	150	10
Black beans	30	150	7
Chickpeas	10	150	3
Chickpeas, canned in brine	38	150	9
Navy beans	31	150	9
Kidney beans	29	150	7
Lentils	29	150	5
Soy beans	15	150	1
Cashews, salted	27	50	3
Peanuts	7	50	0
PASTA and NOODLES
Fettucini	32	180	15
Macaroni	47	180	23
Macaroni and Cheese (Kraft)	64	180	32
Spaghetti, white, boiled	46	180	22
Spaghetti, white, boiled 20 min	58	180	26
Spaghetti, wholemeal, boiled	42	180	17
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	55	20	6
Potato chips	51	50	12
Pretzels, oven-baked	83	30	16
Snickers Bar®	51	60	18
VEGETABLES
Green peas	51	80	4
Carrots	35	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)	46	100	7
Pizza (plain baked dough, parmesan cheese and tomato sauce)	80	100	22
Pizza, Super Supreme (Pizza Hut)	36	100	9
Honey	61	25	12