Blood sugar control is the goal of people who are either prediabetic or diabetic (type 1 or 2).
- High sugar levels slowly erode the ability of cells in your pancreas to make insulin. The organ overcompensates and insulin levels stay too high. Over time, the pancreas is permanently damaged. Insulin resistance may ensue.
- High levels of blood sugar can cause changes that lead to a hardening of the blood vessels, what doctors call atherosclerosis.
Almost any part of your body can be harmed by too much sugar. Damaged blood vessels cause problems such as:
- Kidney disease or kidney failure, requiring dialysis
- Heart attacks
- Vision loss or blindness
- Weakened immune system, with a greater risk of infections
- Erectile dysfunction
- Nerve damage, also called neuropathy, that causes tingling, pain, or less sensation in your feet, legs, and hands
- Poor circulation to the legs and feet
- Slow wound-healing and the potential for amputation in rare cases
Keep your blood sugar levels close to normal to avoid many of these complications.
What is the Glycemic Response?
The glycemic response is the rate, magnitude, and duration of the rise in blood glucose that occurs after a particular food or meal is consumed. It is affected by both amount and type of carbohydrate eaten and the amount of fat and protein in that food or meal.
Refined sugars and starches generally cause a greater glycemic response than refined carbohydrates that contain fiber. This is because sugar and starches alone leave the stomach quickly and are rapidly digested and absorbed, causing a sharp, swift rise in blood sugar. For example, when you drink a can of soda or eat a slice of white bread on an empty stomach your blood sugar increases within minutes. Eating a high fiber food causes a slower, lower increase in blood sugar. The presence of fat and protein also slows stomach emptying, and therefore foods high in these macro- nutrients generally causes smaller glycemic response than foods containing sugar or starch alone. For example , ice cream is high in sugar but also contains fat and some protein , so it causes a smaller rise in blood glucose than sorbet which contains sugar but no fat or protein. In fact, the GI for a baked potato is higher than for a serving of ice cream (due to the fat and sugar).
What is the Glycemic Index? (GI)
Glycemic index is its ranking of how a certain food effects blood glucose compared to the response of an equivalent amount of carbohydrate from a reference food such as, white bread or pure glucose. The reference food is assigned a value of 100 and the values for other foods are expressed relative to this. Foods that have a glycemic index of 70 or more compared to glucose are considered high glycemic index foods those with an index of less than 55 are considered a low glycemic index food.
What is the Glycemic Load? (GL)
Glycemic load (GL) is a method of assessing glycemic response that takes into account both the glycemic index of the food and the amount of carbohydrate in a typical portion. To calculate glycemic load, the grams of carbohydrate in a serving of food are multiplied by that foods glycemic index expressed as a percentage. A glycemic load of 20 or more is considered high, where a value of less than 11 is considered low.
For example: A raw carrot provides about 7 grams of carbohydrate and has a glycemic index of 47. It’s glycemic load (GL) is calculated as:
7 X 47 = 329.
329 / 100 = 3.29
Glycemic load = 3.29
Bottom Line: Some high-GI foods, such as baked potatoes and French bread, are good sources of a number of nutrients. Just because a food has a high glycemic index doesn’t mean it should not be used as part of a balanced diet. Adjusting food choices toward selection of mainly low GI foods is most helpful for people attempting to prevent or control type 2 diabetes.
Type 2 diabetes is usually diagnosed using the: Glycated hemoglobin (A1C) test. This blood test indicates your average blood sugar level for the past two to three months. Normal levels are below 5.7 percent, and a result between 5.7 and 6.4 percent is considered prediabetes. It is important to see your physician who then may refer you to a certified diabetes educator or registered dietitian. Weight and carbohydrate control appears to be the best approach to deal with or even prevent diabetes type 2.
The following links can further discuss the glycemic response as well as provide a table of the glycemic index and glycemic load of 100 foods tested.
The American Diabetes Association
Nutrition. Smolin and Grosvenor, Wiley, 3rd Edition
Nutrition Now. Judith E. Brown, Wadsworth Centage Learning, 7th Edition