Tuesday, September 9, 2008

Glycemic Index(GI) And Bodys Response

Insulin today is considered as a demon and has gotten a bad reputation since high levels of it within the body tend to promote fat storage and make it harder to use body fat for energy. However, insulin is also a very anabolic hormone that can help shuttle nutrients into your muscle cells and promote muscle recovery. When you eat carbohydrates, they are broken down in your system and raise your blood sugar. 

Your pancreas secretes insulin to remove the excess sugar from your blood and deposit it into fat stores  muscle glycogen stores, or liver glycogen stores. If your muscle and liver glycogen stores are already full, the excess blood sugar will be stored as fat. If your muscle glycogen stores are depleted such as after an intense workout, insulin secreted in response to a high carbohydrate meal will push the excess blood sugar and other nutrients into your muscle cells. This is one time when insulin is very good and helps promote muscle protein synthesis (recovery). The degree to which ingested carbs will raise your blood sugar depends on the quantity of carbs you ate and how fast they are digested. Factors such as the quantity of fiber the carbs contained, along with how much protein and fat you ate in combination with the carbs all affect how quickly the carbs are digested.
Generally speaking, the more unrefined and fibrous the carbohydrate source, and the more protein and fat eaten with the meal, the slower the carbohydrate will be digested, and the lower and more steady the blood sugar and insulin response. Slow and steady carbohydrate sources are ideal because they give you steady energy levels, reduce cravings, and allow your body to utilize fat for energy in addition. More heavily refined starches and sugars where the fiber has been removed will be digested much more quickly and cause a higher blood sugar spike and subsequent crash after insulin has done its job. People who eat a lot of refined processed carbohydrates typically go through these cycles of blood sugar spikes and crashes, which causes them to crave more carbohydrates and leads to body fat gain. 

A little known fact is that carbs are not the only food substrate that can promote an insulin response. Large doses of certain free form amino acids and quickly digested proteins such as whey protein also can trigger an insulin response.

One of the methods that was devised originally to help diabetics manage their blood sugar properly was the glycemic index (GI) of foods. The GI basically categorizes foods (generally carbohydrate sources) into low, moderate, or high on the GI scale.

 Basically, foods that raise your blood sugar quickly will have a higher GI and foods that raise your blood sugar slowly and to a lower degree will have a lower GI. 

Examples of foods with high GI’s are white rice, white bread, white potatoes, corn flakes, crispy rice cereals, sugars (except fructose), ice cream, bananas, cooked carrots, candy, and any other refined carbohydrates where the fiber has been removed.

Examples of foods with lower GI’s are most dairy products, most fruits and vegetables, whole unrefined grains, sweet potatoes, barley, beans, and most other higher fiber carbohydrate sources. 

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