The Glycemic Index: What You Should Know

Your body is full of delicate balancing acts. Different chemicals are constantly competing to counteract each other and keep things running smoothly, in a process clinically known as homeostasis. This ability to self-regulate allows our bodies to maintain a healthy temperature, blood pressure and water levels. Another important example of homeostasis that has been receiving a lot of attention lately is blood sugar, or blood glucose.

Many diet programs utilize the glycemic index, a measure of how food affects your blood sugar levels, to achieve certain health benefits. How is blood sugar naturally controlled? How does food affect our blood sugar? What benefits can you expect from monitoring the glycemic index of your diet?

How Blood Sugar Works

Sugar, in the form of glucose, is used throughout your body as fuel at the cellular level. Generally, a healthy level of glucose in your blood is between 90 and 110 mg/dl, which ensures your cells have all the fuel they need to get their job done without being damaged. These levels are maintained by two hormones, insulin and glucagon, both released by the pancreas.

Insulin is the weapon of choice when blood sugar levels are too high. Once it’s in the bloodstream, insulin makes the cells absorb more sugar and tells the liver to store some for later use. This pulls the sugar from the blood and stops any potential damage.

Glucagon is released when blood sugar levels are too low and basically undoes the effects of insulin. This hormone signals to the liver that it’s time to release stored glucose into the blood, raising sugar levels.

When you eat, the carbohydrates in your food are broken down into sugar, which causes a spike in your blood sugar levels. In response, your body begins the cycle of insulin and glucagon to try to regain balance. The varying effects of food on your blood sugar is called the glycemic index (GI). Foods with a high GI are absorbed rapidly, making your blood sugar shoot up quickly and then plummet when insulin is released. Low GI foods digest slower and do not have such a drastic effect on your blood sugar.

Can It Help You Lose Weight?

Various diets attempt to control your blood sugar levels by means of this glycemic index, focusing on foods with a low GI that will have little effect on your blood sugar.

Although this type of diet is beneficial for people with blood sugar issues, diabetes or other related conditions, it is frequently used for weight loss. By nature, this diet will limit your intake of high-carb foods since these typically have a high GI. Compared to other low or no carb diets, though, a glycemic index diet is generally easier to follow because you don’t have to count carbs. This accessibility and sustainability make a glycemic index diet attractive. But does it work?

Lab results are mixed. Some studies have shown no more weight loss from following a GI diet than from following any other program, while others demonstrate a much higher potential for weight loss. Part of the problem could be the wide variation in GI diets leading to an inconsistency in testing. Usually, however, the GI diets that do cause weight lose encourage high fiber and protein intake which contributes to lower portions.

If you do plan on following a GI diet, Dr. David Katz, writing for U.S. News, stresses the importance of using the GI only for its intended purpose: measuring the effects of carbohydrates on blood sugar. Katz points out that these diets pay no attention to other vital nutrients like protein, fats and fiber and paint an unbalanced view of nutrition.

For weight loss, the GI can be incredibly useful to help you decide which carbohydrates to eat, but should be used in conjunction with a balanced diet.

Performance Enhancing Potential

Because carbohydrates are the main fuel used during endurance training, it seems logical that a high GI drink during exercise would be useful. However, a 2009 study published in the Journal of Science and Medicine in Sport found no difference in performance from high or low GI drinks. The researchers did note, though, that a low GI meal before exercise lessened the effects of cortisol, which causes your body to store fat.

Have you followed a glycemic index diet? Please share your experience with us in the comments.

Sources

http://www.pc.maricopa.edu/Biology/pfinkenstadt/BIO201/201LessonBuilder/UnitOne/Homeostasis/index.html

http://www.mayoclinic.com/health/glycemic-index-diet/MY00770

http://health.usnews.com/health-news/blogs/eat-run/2012/10/18/use-and-abuse-of-the-glycemic-index

http://www.ncbi.nlm.nih.gov/pubmed/18789762

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