You may be confused about whether carbohydrates are essential sources of energy for your body, or dangerous food components that raise your blood sugar levels. The truth is that not all carbohydrates are the same, and the glycemic index is a system that ranks foods by their impact on your blood sugar. Learning about the glycemic index can help you make the best decisions for a healthy diet, but if you have concerns about your blood sugar, consult a doctor.
Definition
When you digest carbohydrates, they go into your bloodstream as glucose, or sugar, and the glycemic index of a particular food describes how fast and strong the impact of that food is on your blood glucose levels. MayoClinic.com notes that only foods with carbohydrates have a glycemic index because fat and protein do not drastically increase your blood glucose levels. High-glycemic index foods reach your bloodstream quickly, but carbohydrates from foods with a low glycemic index do not reach your blood as quickly, or cause as big of an increase in your blood sugar levels.
Influential Factors
While it is impossible to know the glycemic index of each carbohydrate food without looking it up, there are some general patterns. Fiber slows down digestion, and foods that are high in fiber tend to be low on the glycemic index. In addition, protein and fat in a food can lower the glycemic index. Riper fruits and vegetables are easier to digest, and they have a higher glycemic index than less ripe ones. More refined and processed foods that are cooked or in smaller pieces also tend to have a higher glycemic index.
Glycemic Index Lists
Values for glycemic index are relative to white bread or glucose with a value of 100, and you can look up the glycemic index for various foods on lists such as the ones from MayoClinic.com or the Linus Pauling Institute Micronutrient Information Center. Low glycemic index foods have values below 55 when compared to glucose with a value of 100, and some examples are beans, peanuts, high-fiber cereal and raw apples. Some moderate glycemic index foods are corn and pineapples, and high-glycemic foods, with a glycemic index over 70, include baked potatoes, candy and white rice.
Glycemic Index and Health
A low glycemic index diet may provide some health benefits. It may help you control your weight because many low-glycemic foods are low in calories but high in fiber and protein, which can make you less hungry. According to the Harvard School of Public Health, a low-glycemic diet may also help reduce your risk for diabetes or control your diabetes if you already have it because low-glycemic foods are less likely to cause your blood sugar to spike. If you do have diabetes, consult your doctor for the best way to manage it.
Sports Nutrition
If you are an athlete or you exercise regularly, the glycemic index can be a useful tool to help you get the best results. Since your body digests low-glycemic carbohydrates slowly, Iowa State University Extension recommends eating them before a workout for sustained energy throughout your exercise session. After a workout, eat high-glycemic foods for faster muscle recovery and glycogen replenishment. Avoid high-glycemic foods before a workout because they can lead to blood sugar spikes followed by hypoglycemia, or low blood sugar.
References
- Harvard School of Public Health: The Nutrition Source: Carbohydrates: Good Carbs Guide The Way
- Linus Pauling Institute Micronutrient Information Center: Glycemic Index And Glycemic Load
- Iowa State University Extension: Eat to Compete: Carbohydrates
- MayoClinic.com: Glycemic Index Diet: Losing Weight With Blood Sugar Control
