The glycemic index of food is among the most widely used modern criteria in classifying foods. But what exactly is the glycemic index? It is simply a measure of how certain food (containing carbohydrates) affects blood sugar and insulin levels.
The value of a food’s glycemic index is dependent on its ability to raise the glucose levels and how rapidly it does so. The rankings of GI (glycemic index) are generally classified into high, medium, low, and very low.
Foods with high glycemic index increase the blood glucose levels rapidly and by large values whereas those with low glycemic index cause a little increase in blood sugar levels if any.
Why the Glycemic Index of foods is important to health
Between thirty and forty-five minutes after eating, the blood glucose level goes through a peak before progressively recovering its initial value. But our body does not digest and assimilate different foods at the same speed, it depends on the type of nutrients that compose them, the amount of fiber they contain and the composition of the food already present in the stomach and intestine.
The normal functioning of the human body is such that when food is taken into the body it is broken down into smaller parts constituting these foods. Carbohydrates are broken down into sugars that are the building blocks.
During the digestion process, these are absorbed into the blood where they make up the blood sugar levels. These levels need to be maintained at optimal levels. When these levels fall either too low or too high, a health condition occurs.
The mechanism by which the maintenance is achieved is a complex procedure involving the release of insulin and glucagon hormones by the pancreas.
When an excess of blood glucose occurs, insulin acts to convert it into glycogen stored in the liver and muscles. When there is too little blood sugar, the glucagon converts the stored glycogen to circulating glucose.
This mechanism ensures that there are only adequate amounts of glucose in the blood at a given time.
Glycemic Index Food Video
When the glycemic index of a portion of food is high, it causes a rapid rise in blood sugar that makes insulin’s work difficult to accomplish. The amount of blood sugar, therefore, remains high for long which is not good for the health of any human.
Intake of high glycemic index foods has been shown to increase the risk of diseases associated with high blood sugar levels. These include cardiovascular diseases, weight gain, obesity, stroke, depression, gallstones, type 2 diabetes (due to insulin resistance in body cells as a result of too much insulin release aimed at curbing the high sugar levels), metabolic syndrome and so on.
On the other hand, the glycemic index of foods could be low, and these have been noted to have no harm to the healthy living of a person. They have actually been proven to reduce the risk of getting the above conditions.
Glycemic index of foods measurement and its application in dietary plans
During previous times, the total amount of carbohydrates in food was what was used to decide what dietary plans were appropriate for special groups of people in the society such as pregnant women, those who want to lose weight and the obese among others.
With the understanding of the glycemic index, however, the use of this information was termed as obsolete. This is because not all carbohydrate in food is absorbed into the blood system.
The absorption rate is not directly proportional to the carbohydrate levels of food but is dependent on several other factors such as chemical composition.
For instance, whole grains contain a lot of carbohydrates but have a lower glycemic index than glucose which has less carbohydrate content.
The glycemic index of foods is measured in accordance with the serving that will give 50grams of available carbohydrate. Available carbohydrate is that which will be readily digested, absorbed and metabolized by the body.
This is the only portion of carbohydrate food that will affect the blood sugar levels. Once this serving amount has been determined, the glycemic index of every food is determined experimentally by allowing volunteers to take the food serving after which their blood sugar levels are measured in two-hour intervals, and the results plotted on a graph.
The area under the curve shows the impact of the food on blood glucose or sugar levels. Comparing the particular food’s effect on blood sugar levels to the effect of pure glucose and white bread is what is used to determine the glycemic index of foods.
Eating a carbohydrate-rich meal in the four-hour period before exercise improves endurance or performance during prolonged moderate-intensity exercise.
The vast majority of studies show that consuming carbohydrates before exercise has a positive impact on performance.
When purchasing foods, it is important to check the glycemic index of a portion of food and avoid those with high values.
The range is from one to a hundred arbitrary units with 0-55 being termed as low glycemic index foods, 56-69 as medium and 70 and above as high. This will normally be indicated on the package of processed carbohydrates.
Healthy dietary plans are those incorporating food with a low glycemic index that would otherwise affect the health of a person negatively.