Cheers to everybody! We are getting through the nutrition topics and our next stop is glycemic index! It’s a very interesting indicator, which can explain why the same amount of calories from a chocolate bar chocolate will have totally different results on your body than from a bowl of porridge. And, despite “scientific nature” of this index, I’ll try to make this info-post as simple and clear as possible. However if it will seem to you a little bit complicated, don’t hesitate to write about this in comments!
Glycemic index (GI for short) measures the impact from food on sugar level in blood after consumption. The starting point is the reaction of body for pure glucose which index is equal to 100.
Already at this point you may start asking yourself - why have I decided to tell you about all this stuff? The answer is quite simple! Because glycemic index indicates how quickly does one or another meal is being absorbed. If meal has a low glycemic index (55 or less), then consuming it will slowly increase the sugar level in blood, and if meal has high GI (70 or more) then sugar level will rise faster. It is the glycemic index which answers the question: why you are soon hungry again after eating a chocolate bar and not so soon after eating a bow of porrige.
Imagine your body as a steam boiler in a train. In order for it to move further you have to put more logs into boiler. Logs can be different: big and small, dry and wet, there also various wood species (high quality and not so high). Good logs will burn for a long time and keep the train moving, bad ones will quickly burn outm thus creating the need to be constantly thrown into the furnace. The same principle with "good" and "bad" carbohydrates. "Good" ones will be longer absorbed by your body, while the "Bad" ones will cause sharp rise of sugar level in blood, and then you’ll have to “refuel” yourself again.
But that’s not all. Fast carbohydrates while saturating your blood with excessive quantity of sugar also leads to a secrete of a large amount of insulin, which saves excesses into subcutaneous fat. As a result, your body has got more fat, but haven’t received so much needed nutrients. Moreover, when you raise the insulin level in your body, it switches to the “accumulation” mode when it’s almost impossible to “burn” fat.
Of course, everything is not so unambiguously as it may seem at a first glance. Most of the time you should really make a choice in favor of products with low glycemic index, but there’re also reverse cases. For example, you need to rapidly recover or boost up before upcoming training session. This is the topic for ADVANCED block of our program (though you can find the information about this issue in the internet by yourself ), and right now let’s limit our knowledge with what I’ve already told before. Glycemic index of food depends on several factors: type of carbohydrates and amount of fiber contained in it, method of thermal processing, contents of proteins and fats:
Type of carbohydrates – fast carbohydrates have higher glycemic index, complex (or slow) have lower. Amount of fiber – more fiber leads to the lowe glycemic index Method of thermal processing – glycemic index usually rises after thermal processing Contents of protein and fats – more of them in the meal leads to the lower glycemic index
Why do we need to eat food with low GI?
* It allows you to stay "full" for longer period of time
* It lowers insulin level
* It lowers the level of bad cholesterol
* It raises the level of good cholesterol
* It allows to control sugar level in blood
* It improves skin condition
* It improves general physical and health condition
* It increase productivity
* It reduces the chance of cardiovascular deceases development
* It redueses the chance of development of various cancer types
* It reduces the chance of some types of eye deceases development
* It reduces the chance of type II diabetes
(* According to “Glycemic Index Foundation”)
5 things you should know about GI
You can calculate GI only for meals which are rich of carbohydrates. It’s nearly impossible to count GI for food contained very few carbohydrates, therefore for meat, fish, poultry, eggs, cheese, nuts, oil, and for most of vegetables GI doesn’t count at all.
Glycemic index for the very same meal can vary from one information source to another. Different methods of food growing and processing, different ways of cooking, condition of the product and various methods of measuring – all this can affect on GI value.
Glycemic index is not the only indicator of food healthiness. Therefore you should not focus only on it. For example, there’s such a beautiful thing as potato which, despite its high GI, is also rich in various healthy nutrients. At the same time there’s not so much beautiful thing as bakery, which, despite its low GI, is full of fats (mostly saturated). That’s why in addition to GI it’s better to take other indicators into account.
Don’t be afraid of food with high GI. As I’ve already written above, GI is not the only indicator which you should rely on making your food choices! Generally you can include food with high GI in your diet, your goal is to keep low the overall glycemic index of consumed food.
Don’t try to calculate GI every day. Firstly, it's very exhausting (even more exhausting than calories calculation). Secondly, I wrote above that there are different ways to affect on the GI value. Just follow the principle of splitting products into categories: High GI, Average GI and Low GI, and try to make your diet mainly from the products of third category.
You can find a lot of various tables with glycemic index of basic diet meals on the internet. Quite often you will find different value of GI for the same products (we have already explained that fact above), therefore it’s more important to look not at the absolute value of GI but at relative values of products to each other. Here’s the example of such table: