Carbohydrates are a source of energy for the body and are found mainly in plants. Eating carbohydrates causes an increase in blood sugar levels, also known as blood glucose levels. The body maintains a healthy blood glucose level, and in response to increases in blood sugar, the hormone insulin is released which helps cells absorb this energy and store excess energy for later use.
The length and the magnitude of this increase, known as the glycemic response, vary with different foods. A diet that results in high blood sugar levels means prolonged exposure to insulin which, over time, can cause obesity, heart disease, diabetes and cancer. Glycemic response is assessed using the glycemic index and glycemic load.
The glycemic index (GI)
This is a measurement of carbohydrates on a scale from 0 to 100 according to the effect they have on blood sugar levels after eating. High GI foods (with indices higher than 70) are those which are rapidly digested and absorbed and result in considerable fluctuations in blood sugar levels. Low GI foods (with indices lower than 55) are more slowly digested and absorbed resulting in gradual rises and falls in blood sugar and insulin levels.
Low GI diets support weight management because they help control appetite and delay hunger. They have been shown to improve both glucose and lipid levels in people with type 1 and type 2 diabetes, and to reduce insulin levels and insulin resistance. Studies from Harvard School of Public Health indicate that the risks of diseases like type 2 diabetes and coronary heart disease are strongly related to the GI of the overall diet. The World Health Organization (WHO) and Food and Agriculture Organisation (FAO) recommend that people base their diets on low-GI foods in order to prevent diseases of affluence, such as coronary heart disease, diabetes and obesity.
What is the difference between glycemic index (GI) and glycemic load (GL)?
How high blood glucose rises after a meal and how long it remains high depends on the quality of the carbohydrates (the GI) as well as the quantity. Glycemic index is not based on typical serving size, but on the blood sugar response to consuming 50g of carbohydrate in a given food. You would have to eat over a pound and a half of broccoli to consume 50g of carbohydrates, whereas that amount is found in 1 cup of rice. Glycemic load or GL takes into account the GI of a food as well as the amount of carbohydrates per serving. A glycemic load of 20 or higher is considered high, while 10 or below is considered low.Follow these guidelines to help you minimize blood sugar fluctuations and better manage your energy levels and weight:
- Eat plenty of fiber-rich vegetables such as dark leafy greens, beans, and fruits with their skin such as apples, pears, peaches, and berries.
- Limit potatoes and corn to small side dishes.
- Eat whole grains as much as possible. Instead of refined and white breads chose those made from stone-ground whole wheat or sprouted grains. Use basmati, brown and long grain rice instead of jasmine and arborio varieties.
- Avoid sugar-sweetened beverages, and drink no more than one cup of 100 percent fruit juice daily.
- Consume protein and fat as well as carbohydrates at most meals and snacks. This combination of nutrients will help keep your blood sugar balanced and minimize hunger. Nuts, beans and seeds are great sources of protein and fat. Cold-pressed vegetable oils, coconut oil and avocados are also good sources of healthy fats.
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