What is Glycemic Index (GI)?
The scoring is between 0 to 100 with glucose being the reference food with a GI value fixed at 100. It is a new system of classifying carbohydrate containing foods, according to how quickly they raise blood glucose levels in the body.
The term ‘GLYCEMIC INDEX’ (GI) was first invented by David Jenkins & Thomas Wolever at St. Michael hospital in Toronto, Canada in 1981. Since then, it has been a subject of debate. More recently, an effort to expand GI has been made by Jennie Brand-miller & her associates in Sydney, Australia.
To better comprehend GI index, we need to understand that all carbohydrates, from starches to plain sugar (commonly called as “Table sugar”), share a basic biological property i.e. they can be digested and converted to glucose in our body. The common misconception among the general public is that by avoiding ‘plain sugar’ they can avoid diabetes and take care of their ‘sugar’ level in the blood. I do not eat any ‘Mitha’ (‘Mitha’ means sugar in Hindi); is a common reply from the patients when they are asked to avoid sugar.
When a doctor or dietician refers to ‘sugar’ in the food, they mean Carbohydrates and the patient understands it as table sugar.
GI is possibly one of the scientific ways of looking at carbohydrate- rich food and finding out which item when consumed is likely to increase the level of glucose in the blood.
Carbohydrates with high GI causes a rapid increase of blood sugar, whereas diet based on low GI are low in sugar but high in fiber. They cause a slow rise of blood sugar and are, therefore, ideally suited for diabetic patients.
Here’s a quick overview of what’s high and what low In GI is
|Low GI||55 or less||Most fruits and vegetables (except potatoes, watermelon), grainy bread, brown rice, fish, egg|
|Medium GI||56-69||Whole wheat products, basmati rice, sweet potato, table sugar, white rices|
|High GI||70 or more||Flakes, rice krispies, baked potatoes, white bread, straight glucose (100)|
Importance of Glycemic indexOur body has an obligatory requirement for glucose depending on metabolic demands of our body. It is usually around 200gms/day. Our brain completely depends on glucose and oxygen.
Maintaining a constant blood glucose level is important for our health and well being. Both low or high levels can be dangerous, sometimes even fatal. If you are feeling lethargic and hungry during the day after hard work , it is most likely due to low blood glucose level.
- Blood sugar level below 40mg/dl (known as ‘Hypoglycemia’ in medical terms) causes coma, stupor and even death.
- Blood sugar level more than 180mg/dl (known as ‘Hyperglycemia’ in medical terms) causes long-term complication of diabetes mellitus.
- Levels above 300 to 500 mgs/dl can cause acidosis and also lead to a state of coma Excess glucose that is stored is most often converted to fat. Food with high GI makes you initially feel very energetic but as the fat increases, with time, it makes you lethargic.
- Lowers risk of heart disease.
- Prevents Type 2 diabetes (Genetically determined diabetes where the individual body is resistant to insulin actions).
- Help to evade serious side effects, if you have diabetes.
- Curbs appetite, so you lose weight.
- Helps to feel more energetic and this is important for a person’s well being.
GL of 10 or below are considered low whereas 20 or above are considered high. So if you love to eat food with High GI then try and consume very little for the purpose of your satiety, so that GL is kept less than 10.
Glycemic Index and Weight LossGLYCEMIC INDEX (GI ) diet programs are highly successful for weight loss and all diet plans for this are based on GI. For sustaining weight loss the person should have some knowledge about the foods that have high GI and avoid them. The common food includes refined carbohydrates (white bread), sweets, puddings, desserts, cakes, potato and rice to name a few.
The Insulin Connection - A surge in glucose causes high secretions of insulin from the islets of Langerhans in your pancreas. The insulin helps to push the glucose inside the cell for its utilization. Constant insulin production results in overworked islets and eventually over a period of time results in diabetes. Keeping your glycemic load below 10 helps avoid diabetes and keeps your weight under control.
|Effects of eating high GI food||Effects of eating low GI foods|
|Cell dysfunction||People tend to lose weight|
|Increased insulin production||Increase the body’s sensitivity to insulin|
|Increased free fatty acid accumulation in body||Reduce blood cholesterol levels|
|Raise the risk for obesity, type 2 diabetes and heart disease||Reduce the risk of heart disease, reduce hunger, refuel carbohydrate stores after exercise|
ConclusionsOnce you have understood these basic concepts of GI plan out your diet sensibly. Speak to a dietician, tell them what food you like and what you don’t and they would help you with a diet plan for loosing weight. For diabetics, it is essential to understand these concepts to control their 'sugar' or rather glucose level in the blood.
Latest Publications and Research on Glycemic IndexGlycemic index treatment using Japanese foods in a girl with lennox-gastaut syndrome. - Published by PubMed
Ileal Interposition with Diverted sleeve gastrectomy for treatment of Type 2 diabetes. - Published by PubMed
Comparision between body mass index and abdominal obesity for the screening for diabetes in healthy individuals. - Published by PubMed
Clinical Profile of Long-Term Survivors and Nonsurvivors With Type 2 Diabetes. - Published by PubMed
A Study of Glycemic Response to Corinthian Raisins in Healthy Subjects and in Type 2 Diabetes Mellitus Patients. - Published by PubMed