The Glycemic Index (GI) and The Glycemic Load (GL)
“A straightforward explanation and what it means for your health”
When you eat carbohydrates, no matter what that food is, be it healthy, not so healthy or anything in between, it will ultimately have a direct impact upon your blood sugar (glucose) levels because the body turns all carbohydrates into either simple or complex sugars which are then released or stored as energy depending upon what the body needs at any one time.
Carbohydrate is the food source that raises blood glucose level abruptly after meals. Not fat, protein, vitamins or minerals. Just carbohydrate.
So why is this important you may ask?
On average blood sugar levels rise and fall throughout the day, according to what you eat, when you eat it and how active and healthy you are. Rapid and sudden rises to the blood sugar levels create ‘spikes’ which short-term are completely normal and are not harmful in the short term. Even walking or jogging will raise your blood sugar levels.
The Glycemic Index
The Glycemic Index, or GI for short, measures how quickly or slowly carbohydrates are broken down during digestion, and how fast the carbs are turned into glucose which is then released into the bloodstream. All carbohydrates are turned into glucose (sugar) in the body. This is how the body creates energy and which you explains the sudden sugar rush you might feel after you have eaten something high in processed sugar.
Foods that have a high GI and which will therefore create that immediate blood sugar spike include items such as ice-cream, cake, chocolate and sweets, which would explain why children eating too many sweet foods tend to race around as if they are on speed.
Of course anything with refined sugar in it will spike your blood sugar levels, but it isn’t just sugary foods that are rapidly turned to glucose in the body. Other ‘high GI’ foods include –
- Bread and bread products including waffles and bagels etc (white is the worst)
- Fizzy Drinks
- Breakfast Cereals including instant oatmeal and puffed wheat
- Rice and Rice Cakes
- Couscous (contains wheat)
- Macaroni cheese
- Baked Potatoes
Controlling your blood sugar levels is therefore critical for maintaining an anti-inflammatory state in the body in order to keep everything functioning at an optimal level. Just like a well oiled machine.
In the long-term however, if you are consistently experiencing these spikes after eating, especially if a typical day for you consists of –
- Toast and jam or shop bought cereal for breakfast
- Cheese and Crackers for Lunch
- Fizzy Drinks and chocolate throughout the day
- Pizza for dinner
– you are going to raise the ‘average’ level of sugar in your blood. Anyone who has long-term elevated blood sugar levels is at a much greater risk of developing complications such as –
- Heart disease
- Cardiovascular disease
- Type 2 diabetes
- Metabolic syndrome (a combination of diabetes, high blood pressure and obesity)
- Chronic kidney disease
- Formation of gall stones
- Neural tube defects (defects of the brain, spine, or spinal cord)
- Formation of uterine fibroids
- Cancer of the breast, colon, prostate, and pancreas
Uncontrolled blood sugar can also damage the vessels that supply blood to important organs such as the heart, kidneys, eyes, and nerves. This can occur even when you think you feel OK.
This is why it is so important to take action as soon as you’re diagnosed with diabetes. Our bodies are amazing, but unfortunately once you have a heart attack, stroke, your kidneys fail or you lose your sight, the damage cannot be undone.
The Glycemic Load
When considering the effects of blood sugar levels on our long term health, The Glycemic Load or GL for short also plays an important part. Unless you are a health professional or seriously dedicated to food GI levels, you probably won’t really understand which foods have a high or low Glycemic Index and which ones are best for slow blood sugar release.
Now for the science bit!
The GL measures how much a food has to potential increases blood sugar levels, varying from 1 (low GI) to 100 (high GI). It calculates GI in food using the following calculation –
GL = (Glycemic Index x amount of carbohydrates being eaten, divided by 100)
For instance, the calculation for a 1/2-cup serving of raw carrots, which has about 8.6 grams of available carbohydrates and a glycemic index of 45 =
45 x 8.6 = 387 divided by 100 = 3.9 (which is a low glycemic load)
So how do you count carbohydrate levels in food?
When it comes to carbohydrate counting, taking time to read the food labels is key. Food labels must list (amongst other things) the grams of total carbohydrate content as well as grams of sugar and fibre in a single serving of the food item. Although not required, some food manufacturers also list the amount of soluble fibre, along with sugar alcohols and “other” carbohydrates (typically starches) below the total carbohydrate content.
Of all these items, the total carbohydrate amount is by far the most important. This includes everything in the food that is a carbohydrate including starch, fibre, sugars, and sugar alcohols. Look for the number next to the little “g” (which stands for grams).
Even though you won’t actually find a food’s glycemic index or load on a food label, the nutrition facts label is a valuable tool for finding the best low-glycemic choices, as well as the best foods for weight loss. Knowing what to look for on the label can make life easier for you as you navigate the grocery store aisles.
Foods that have a higher carbohydrate content per serving will have more of an effect on blood sugar levels than those with only a small amount of carbohydrates. The source of the carbohydrates in the food is particularly important, because foods that contain more processed versions of carbohydrates have a greater effect on blood sugar levels than those from whole foods. This means foods made with flour or sugars often have a higher glycemic index than foods made with intact whole grains.
When counting carbohydrates, it is not necessary to know how much sugar a food item contains. Remember, sugars are simply a type of carbohydrate and are included in the total carbohydrate listings on the label anyway.
Remember this simple rule –
The higher the carbohydrates in a product, the more it will raise blood sugar levels
One other factor to be aware of when label reading is to take notice of serving sizes (portion sizes). The serving size listed on the label may not be what you normally consume. If the portion you eat is smaller or larger than the stated serving size, you will need to adjust the carbohydrate total accordingly. If a serving size is 1/2 cup and you have 1 cup, you will need to double the carbohydrate amount.
Foods with low and very low GI
Soybeans and Tofu
Beef, chicken, lamb and turkey (grass fed only)
Grains (barley, buckwheat, oats, quinoa, rye)
Black pepper, Chilli
So to fully eat a low GI diet, the key is to always eat fresh fruit, vegetables and whole foods, staying away from processed and high sugar products.
Taking advantage of the health benefits of a low GI diet simply consists of eating whole, natural foods that are either low or very low in their GI value.
Please be aware that eating fruit is not going to spike your blood sugar levels despite many dieters worrying that fruit is sugar and sugar must be avoided at all costs. Fresh fruit contains an abundance of antioxidants and vitamins and the sugar they contain is bound up with a vast amount of fibre so will not spike your blood sugar. In fact, a life without fruit is like the world without the sun. To be truly healthy we should consume a daily amount of fresh fruit and vegetables.