Understanding the Glycemic Index

Understanding the Glycemic Index

We change our body chemistry every time we eat. In fact, diet is more powerful in preventing common diseases than either drugs or medical care. Learning about the glycemic index will help you reduce and prevent inflammation, stay slim, and reduce your risk of chronic diseases.

Glycemic Index 101

A few decades ago, all we knew was to eat less simple carbs and more complex carbs.

We now know this advice was too simplistic. Our bodies respond differently to the many types of complex carbohydrates.

The glycemic index is a more accurate guide to carbohydrates and other foods. Foods are given a number depending on how much they raise your blood sugar level. High-glycemic foods make your blood sugar level shoot up. Low-glycemic foods keep your blood sugar relatively stable. Foods lie along the spectrum from low to high-glycemic with numbers from 0 to 100.

How Your Body Reacts to High Glycemic Foods

Let’s dig into some biochemistry.

Here’s what happens when you have some high-glycemic food like white bread. First, your blood glucose levels shoot up as your body breaks down the white bread. The β-cells in your pancreas are triggered to action by the spiking blood glucose and work quickly to secrete insulin. High amounts of insulin are released and your blood glucose levels drop sharply. Your blood glucose levels get on the biological equivalent of a roller coaster. Compare that to how your body responds to a low-glycemic meal. Instead of spikes in blood glucose and insulin levels, your body only experiences a gradual increase in blood glucose and the pancreatic cells don’t have to work furiously to produce the insulin you need. You still with me? Here are some long-term effects of high-glycemic foods.

The Negative Effects of High-Glycemic Foods

1. Your risk of diabetes increases

If your pancreas constantly works overtime to produce enough insulin, it will fail. If your pancreas can’t produce enough insulin after each meal, your risk of type 2 diabetes increases.
Here are some common foods linked to diabetes: white bread, breakfast cereals – many of them claim to be whole-grain although they aren’t, white potatoes, corn, soda[link to soda post], and other sweetened drinks.

2. Your risk of cardiovascular disease also rises

We now know eating high-glycemic foods is linked to increased serum triglyceride and lower HDL (‘good’) cholesterol. Both increase your risk of cardiovascular disease.

3. Obesity becomes a problem

Your blood sugar level is tightly linked to how much you feel like eating. A lot of food cravings are caused by low blood sugar. Sugar and foods that quickly break down into sugar also make you tired, irritable, and inflamed. Also, if your blood sugar falls sharply, you’ll likely start munching. Let’s go back to what happens to your blood sugar level after a high-glycemic meal. Your blood sugar level shoots up as your body breaks the food down, then plunges when the pancreas releases insulin. Your body craves food when your blood sugar is low and signals you to eat again.

The cycle repeats. Your blood sugar shoots back up. Insulin is released. Your blood sugar drops. Once you get on this biochemical roller coaster, it takes a while before you can get off. Each time this cycle repeats, you consume more calories.

The Nitty-Gritty of the Glycemic Index and Glycemic Load

Here’s how to decipher glycemic index readings:

Category Glycemic index
Low GI 1-55
Medium GI 56-69
High GI 70 and higher

Stick to foods from the low GI category and eat some foods from the medium GI category. Avoid high GI foods.

You’ll hear the term ‘glycemic index’ more often, but sometimes you’ll hear about a food’s ‘glycemic load’ as well.

Which measure should you use? Here’s the short answer: the glycemic index is used more often and is generally a good guide. The glycemic load gives you a better picture of how much a food will make your blood sugar level rise, so use that if you have it.

Here’s how to decipher glycemic load readings:

Category Glycemic load
Low GL 1-10
Medium GL 11-19
High GL: 20 and higher

More Than the Glycemic Index

The glycemic index is just one of the factors to consider when planning your meals. Make sure you consider a food’s nutrients, vitamins, and calories as well. For example, Gatorade has about the same glycemic index as watermelon. That definitely doesn’t mean they’re both good for you. Watermelon has far more nutrients than any sugary energy drink.

Also, lots of healthy foods may not be on a glycemic index list. Just because you can’t find a food on a list doesn’t mean it’s unhealthy.

Here’s How to Eat a Low-Glycemic Diet

Eat more whole-grain foods. Have some steel-cut oats in the morning with blueberries and almond butter. For a snack, stay away from the cookies and grab some nuts and dried fruit instead. Definitely avoid the soda. At mealtimes, try grains like brown rice, buckwheat, and quinoa. Avoid white bread and eat less starchy foods such as potatoes and corn.

Table of Glycemic Index and Load of Foods

Check out the glycemic index of some of the most common foods. List courtesy of Harvard Health Publications.

FOOD Glycemic index (glucose = 100) Serving size (grams) Glycemic load per serving
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, average 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, average 73 30 10
Whole wheat bread, average 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
Coca Cola, average 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, average 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
All-Bran, average 55 30 12
Coco Pops, average 77 30 20
Cornflakes, average 93 30 23
Cream of Wheat (Nabisco) 66 250 17
Cream of Wheat, Instant (Nabisco) 74 250 22
Grapenuts, average 75 30 16
Muesli, average 66 30 16
Oatmeal, average 55 250 13
Instant oatmeal, average 83 250 30
Puffed wheat, average 80 30 17
Raisin Bran (Kellogg’s) 61 30 12
Special K (Kellogg’s) 69 30 14
Pearled barley, average 28 150 12
Sweet corn on the cob, average 60 150 20
Couscous, average 65 150 9
Quinoa 53 150 13
White rice, average 89 150 43
Quick cooking white basmati 67 150 28
Brown rice, average 50 150 16
Converted, white rice (Uncle Ben’s) 38 150 14
Whole wheat kernels, average 30 50 11
Bulgur, average 48 150 12
Graham crackers 74 25 14
Vanilla wafers 77 25 14
Shortbread 64 25 10
Rice cakes, average 82 25 17
Rye crisps, average 64 25 11
Soda crackers 74 25 12
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, average 33 200 11
Apple, average 39 120 6
Banana, ripe 62 120 16
Dates, dried 42 60 18
Grapefruit 25 120 3
Grapes, average 59 120 11
Orange, average 40 120 4
Peach, average 42 120 5
Peach, canned in light syrup 40 120 5
Pear, average 38 120 4
Pear, canned in pear juice 43 120 5
Prunes, pitted 29 60 10
Raisins 64 60 28
Watermelon 72 120 4
Baked beans, average 40 150 6
Blackeye peas, average 33 150 10
Black beans 30 150 7
Chickpeas, average 10 150 3
Chickpeas, canned in brine 38 150 9
Navy beans, average 31 150 9
Kidney beans, average 29 150 7
Lentils, average 29 150 5
Soy beans, average 15 150 1
Cashews, salted 27 50 3
Peanuts, average 7 50 0
Fettucini, average 32 180 15
Macaroni, average 47 180 23
Macaroni and Cheese (Kraft) 64 180 32
Spaghetti, white, boiled, average 46 180 22
Spaghetti, white, boiled 20 min, average 58 180 26
Spaghetti, wholemeal, boiled, average 42 180 17
Corn chips, plain, salted, average 42 50 11
Fruit Roll-Ups 99 30 24
M & M’s, peanut 33 30 6
Microwave popcorn, plain, average 55 20 6
Potato chips, average 51 50 12
Pretzels, oven-baked 83 30 16
Snickers Bar 51 60 18
Green peas, average 51 80 4
Carrots, average 35 80 2
Parsnips 52 80 4
Baked russet potato, average 111 150 33
Boiled white potato, average 82 150 21
Instant mashed potato, average 87 150 17
Sweet potato, average 70 150 22
Yam, average 54 150 20
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
Pizza, Super Supreme (Pizza Hut) 36 100 9
Honey, average 61 25 12

Chew on this

Keeping the glycemic index in mind when you pick foods will do a lot for you. It’ll even help you stay slim because you’ll be eating more fibre and less sugar.

Eating a low-glycemic diet will be easy. You don’t have to check a glycemic index list each time you eat. Remember the Michael Pollan food rule and you’ll be just fine: “Eat food (not processed). Not too much. Mostly plants.”

Eat well and live well!

Have you made the switch to a low-glycemic diet? Tell us about it in the comments!

2017-06-21T11:53:33+00:00 March 25th, 2016|Nutrition|

About the Author:

For over 20 years Dr. Tick has dedicated herself to researching evidence-based holistic treatments for pain and inflammation. A multiple-book author, including the highly acclaimed Holistic Pain Relief - An In-Depth Guide to Managing Chronic Pain, Dr. Tick empowers her patients to live free of pain and full of life. She is the first holder of the prestigious Gunn-Loke Endowed Professorship of Integrative Pain Medicine at the University of Washington and a Clinical Associate Professor at the University of Washington in the departments of Family Medicine and Anesthesiology & Pain Medicine.

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