You may have noticed the words “low GI” on some of the food you buy and wondered what it meant. GI or the Glycemic Index is the method for measuring what kind of impact various foods have on your system. It was devised approximately twenty years' ago to help with dietary recommendations for diabetics.
Those researchers who worked on the glycemic index found that the effect of a carbohydrate on blood-glucose levels was not actually determined by just any sugar or starch but by how quickly a particular food released insulin into the body after eating. As the blood-glucose levels rise, more insulin is produced and absorbed by body tissue. There are some foods that go through this cycle in quick, sharp spikes while others proceed more slowly and gradually. The former will fall under high GI and the latter under low GI.
Why is low-GI important?
Eating low-GI is an important nutrition message that goes hand-in-hand with other healthy eating guidelines such as consuming less saturated fats while eating more fruit and vegetables.
According to Joanna McMillan-Price, a Sydney, Australia, nutrition scientist and co-author of The Low GI Diet book, GI is a ranking (from 1 to 100) which measures the effect of a food on your blood-glucose level over the two hour period following eating.
She goes on to explain: "You get a bell-shaped curve when you eat food containing carbohydrates; the blood-glucose rises and, as your body produces insulin, it pushes the glucose out of the blood and into tissues, and then you see the blood-glucose level falling. When you eat high GI foods, you get a very high bell curve response with a dramatic drop. With a low-GI food, there is a slower and steadier rise in the blood-glucose level.”
The body can’t always handle those sudden sharp spikes, and it can lead to a higher risk of heart disease, diabetes and other diseases impacted by blood-glucose levels. When it comes to blood-glucose, slower is definitely preferable, enabling your body to process the blood-glucose easier and function better overall.
How does the slowing process work?
This slower processing helps prevent the risk of disease and even weight gain. With low GI food, you feel full for longer so you are less likely to over eat plus your energy levels keep going for longer.
Many of the foods that have a high GI are the more refined and processed foods such as sugary breakfast cereals, white breads and bagels, white rice and potatoes but do include pumpkin, parsnips, watermelon and dates while those with a low GI are the more natural and whole foods such as oats, wholegrain bread, most vegetables and many fruits such as cherries, plums and grapefruit.
For a very helpful GI chart on all types of foods, go to http://www.the-gi-diet.org/lowgifoods/
The number listed next to each food is its glycemic index. The value can vary slightly from person to person and from one type or brand of food and another. For example Special-K produced different results in tests in the USA and Australia because of different ingredients in each location. Nevertheless, in spite of such variation, the index gives you a good idea of what foods to eat and those to avoid.
If you are worried about weight gain and/or cardiac health, eating a low GI food diet is definitely a step in the right direction along with stress relief, plenty of exercise, good quality sleep and all those other important lifestyle choices.