Glycemic index
- ciaralitchfield
- Jan 8, 2015
- 3 min read
Carbs existing everything! The obvious sources include bread, rice, pasta and potatoes but carbohydrates are also present in fruit, veg, dairy and beverages. Sugar is the simplest form of carbohydrate which is why they make up the main energy source in our diets. Sugars can be natural, such as Fructose from fruit and Lactose from milk, but many are added during processing.
They can be divided into ‘Good’ and ‘Bad’ groups.
The Bad carbohydrates are simple sugars. This group includes sugary cereal, deserts, fizzy drinks and refined white bread. These foods are broken down quickly but provide very little but empty calories and a sudden boost of energy. This energy may not be used straight away so will be stored as glycogen inside our cells. If the glycogen remains unused it will be converted to fat. These foods tend to be processed so most of their natural vitamins, minerals and fibre have been stripped away leaving an unnutritious product. On top of this the sudden hit of energy gives your body a taste of the glucose is should be getting so makes you crave more. It’s not unusual to feel tired after eating such a product as your body almost crashes once the energy hit has gone. Continued boosts and crashes of energy can lead to health problems such as type-2 diabetes, heart disease, obesity.
The good carbohydrates are more complex and include such foods as whole grains, bran cereals, fresh fruit and green vegetables. These provide us with lots of fibre and nutrients as well as keeping us full for longer. They do this by making our bodies work harder to break them down into the sugars we need for energy. This process stimulates metabolism and allows the energy provided by the food to be released over a longer period of time keeping us more satisfied. The group is knows as complex as this describes their structure. The chemical structure of the carbohydrate is more fibrous and complex which is what makes breakdown more difficult. Most sugars should come from this source as the energy released is more sustained.
This difference is key to why many of us choose whole grain breads, pasta and rice over the white version. Wholegrain is often lower in sugar as they contain more fibre. The fibre content is key in these products as it affects the nature of the carbohydrate present.
A core concept in making this easier to grasp is something called Glycemic Index or GI. The ability of a carbohydrate to provide either a slow release or quick hit of energy can be graded using the Glycemic index. The GI of a food is determined by the length of time needed for its energy ( given in the form of glucose) to be released into the blood. It’s represented in a graph with Time along the horizontal axis and blood glucose levels along the vertical axis. In the case of white bread, a food with a high GI, its curve would look steep almost like a point. Whole grains breads curve would look more like a gentle mountain where the peak is not so obvious. In general lower GI is better as energy is sustained, the lower the carbohydrate/sugar contents the lower the GI of a food.
Keep an eye out for my ‘Sugar swap’ blog providing tips on how to stick to a low GI diet and rid your routine of hidden sugars.
