Carbohydrates are a major food group and consumed in the largest quantities in the modern diet. Starches like bread, corn, potatoes and rice constitute the bulk of most meals. However, not all carbohydrates are made the same. The quantities of fiber, proteins and vitamins and minerals varies in each type of starch. More importantly though is that the manner in which these carbohydrates affects the blood glucose levels differs. Most starches are complex carbohydrates that are digested and absorbed into the bloodstream as simple carbohydrates, mainly glucose. Glycemic index is a measure of the degree to which a carbohyrate raises the glucose levels in the blood. This is very important for maintaining a constant energy supply for long periods of time, and especially in diabetics and those aiming to control their weight.
Glucose has to be maintained within a narrow range with the bloodstream or it can damage cells in the body. When glucose enters the bloodstream, the pancreas secretes the hormone insulin. This hormone helps to stimulate the cells to take in glucose and consume it for energy production. Other processes are also triggered to reduce the blood glucose level. Excess glucose is stored in the liver as glycogen and some is converted into fatty acids and stored in the fat tissues within the body. When needed the body can call up these stores and use it for energy. This efficient mechanism ensures that the body has a constant supply of nutrients like glucose for energy but at the same time the blood glucose levels are maintained within a narrow range.
These are foods which raise the blood glucose levels faster. This increases the need for the body to secrete insulin and remove the glucose from the bloodstream. High GI foods are also commonly referred to as fast releasing carbohydrates due to its effect on blood glucose. In diabetics, there is a deficiency of insulin and the glucose levels cannot be brought down as quickly as is needed. The circulating excess of glucose therefore damages the body cells. Even in a healthy person, high glucose index foods has a profound effect on energy and body fat. It enters the bloodstream faster and is then quickly removed and stored of fat.
A person will therefore experience a slight ‘sugar rush’ followed by a dip in energy levels. It will also increase the body’s fats stores especially if the calories consumed in a day exceeds the calories needed for daily physical activity. Most foods that are made with refined starches like white flour and white sugar are high GI foods. Some of the other foods which are also high GI includes corn flakes, broad beans, puffed rice, corn and potato chips, parsnips and dates. Therefore these foods should be avoided by those trying to lose weight and diabetics.
Low GI foods do not cause spikes in the blood glucose levels as it gradually enters into the bloodstream. It is therefore commonly referred to as slow releasing carbohydrates. This means that cells in the body can utilize the glucose in the bloodstream for its energy needs without having to store much, if any, away as glycogen or fat. In this way low GI foods are able to sustain a person for longer allowing for a constant supply of energy over a period of time unlike the ‘sugar rush’ experienced with high GI foods.
It is also the better choice of carbohydrates for diabetics who do not have the efficient mechanisms to process high glucose levels in the blood. The more common low GI foods are brown rice, wholegrain foods, most vegetable and fruits, milk and foods made with unrefined starches. Some of these foods are classified as moderate GI and it is therefore important to consult with a dietitian about an appropriate low GI diet. High protein and high fiber can also help to lower the GI of some moderate to high GI foods but only to a certain degree.
The benefits of consuming low GI foods is important to every person irrespective of their age, weight or presence of diabetes mellitus. For the elderly who may not be diabetic, the body’s ability to regulate glucose control with age may not be as efficient and a low GI diet can therefore be helpful even for the non-diabetic. A low GI diet can also help with weight control which is significant in the elderly who are at a higher risk of many chronic diseases. Obesity is a risk factor for many of these major and common chronic ailments and most are exacerbated in a person who is overweight.