Each food containing carbohydrates is assigned a Glycemic Index (GI) value.
The glycemic index (or GI) is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar (glucose) levels after eating.
Carbohydrates with a low GI value (55 or less) are more slowly digested, absorbed and metabolized and cause a lower and slower rise in blood glucose and therefore insulin levels.
Foods with a:
- High GI are those which are rapidly digested, absorbed and metabolized and result in marked fluctuations in blood sugar (glucose) levels
- Low GI carbohydrates – the ones that produce smaller fluctuations in your blood glucose and insulin levels – are one of the secrets to long-term health, reducing your risk of type 2 diabetes and heart disease
The GI can be thought of as a measure of the quality of the available carbohydrate in the food. The GI cannot be applied to foods containing no available carbohydrates (ie. it is meaningless to say, for example, that bacon has a GI of 0).
GI values can be interpreted as follows:
- Low: 55 or less
- Medium: 56 – 69
- High: 70 – 100
If you take a closer look at starchy foods for sale in the supermarket, you might notice something interesting. The price of the product dictates quality, hence the cheaper it is then the poorer the nutritional composition and thus, the GI is higher. I notice this almost every time I go to the supermarket to buy rice or pasta.
Presenting the theory in a more practical way, basically, I recommend you choose groceries that are not over-processed. The same company might have two different products for sale: brown rice and white rice. Their price would be different. The brown one would be more expensive and qualitative.
The difference however between them lies in their GI value and some extra content of fiber, micronutrients and proteins. The easiest way to find all round healthy food choices is to look for the GI symbol.
However, if the GI symbol is not shown on the package then look over the ingredients label and observe that the brown rice has more fiber, proteins and a little fewer calories. Hence, it will definitely affect its GI value as the garnish with better and more nutrients will always have a lower GI.
Let’s take another good example: beans. I think it’s unnecessary for me to state that you should buy raw beans instead of canned beans even if they are both complex carbohydrates.
In other words my friends, I recommend you choose foods with better nutritional composition because the process they undergo while being packaged for sale can compromise their quality.
Try to always read the ingredients label before buying.
Leaving the theories aside for a while, I want to tell you that many healthy foods that we shall eat have a high GI. For example, carrots may have a high GI, but they contain very little carbohydrates, so they do not affect blood glucose very much.
- Simple carbohydrates often lead to a faster rise in blood sugar and insulin secretion from the pancreas – which can have negative health effects.
- Many complex carbohydrate foods contain fiber, vitamins and minerals, and they take longer to digest – which means they have less of an immediate impact on blood sugar, causing it to rise more slowly. But other so called complex carbohydrate foods such as white bread and white potatoes contain mostly starch but little fiber or other beneficial nutrients. Junk food such as burgers, hot-dogs or even white pasta have a high GI.
The GI has several practical applications not only for exercise enthusiasts wanting performance benefits but also for those looking to improve glucose control. Currently, research doesn’t support low GI eating as a magic bullet for weight loss. It comes back to eating less, being more active, and consuming a healthy diet containing plenty of whole grains and other fiber containing foods (e.g., fruits and vegetables). However, others sustain that low GI diets has an impact on weight loss, making it more sustainable over time. My recommendation for you will be to focus more on low GI diet and let the high GI sources to come only from fruits and organic honey. Avoid sweets of any kind.
Simple carbs are quickest source of energy, hence if I want to boost my energy a bit for the upcoming workout then I will most likely grab some watermelon, banana or even honey instead of eating starches. Starchy foods will just require too much time until I will feel energic enough to perform properly. Read more about simple and complex carbohydrates here: Basics of Nutrition.
How does a low GI help?
Overcoming hunger: Low GI foods take longer to digest and help you feel satisfied by triggering natural appetite suppressors. In contrast, high GI foods cause stress hormones to be released, which can stimulate appetite.
Speeds up fat burning: High GI foods cause a sharp increase of blood glucose that triggers the body to release a rush of the hormone insulin. A large surge of insulin will leave you feeling tired, hungry, craving more sugar and also lowers the speed at which the body burns fat. Eating low GI carbohydrate foods causes a steady rise of blood glucose, which only results in a small and gentle rise in insulin. Small increases in insulin keep you feeling full, energized for hours and encourages the body to burn fat.
Going low GI is easy! It’s all about making the right choices:
- Swap high GI foods for low GI foods. Table of Carbohydrate foods, according to GI
- Eat at least one serving of a low GI carbohydrate food at each meal, and choose low GI snacks.
- Keep your eye on serving sizes. Eating too much food, even if it’s a healthy choice, isn’t good for you.
Most people don’t eat too much carbohydrates – they just eat the wrong type. The GI is a scientifically proven way of ranking carbohydrates in food to help you eat only high quality carbohydrates (choose sweet potatoes rather than French fries).