What is low GI?
A food item’s Glycaemic Index (GI) score reflects the amount of carbohydrates present and the overall effect this item has on blood sugar levels. A low GI score means that the food item takes longer to be absorbed/digested thereby releasing energy in the form of glucose slowly into the body. In terms of feeling full, what this does it that it keeps you fuller for longer due to the way such items are digested.
In theory such an approach to a healthy diet could work as it would help individuals with diabetes navigate through food items to help them control their blood sugar levels. Here’s the main items often listed according to their GI score:
Low GI Foods (55 or less)
- 100% stone-ground whole wheat or pumpernickel bread
- Oatmeal (rolled or steel-cut), oat bran, muesli
- Pasta, converted rice, barley, bulgar
- Sweet potato, corn, yam, lima/butter beans, peas, legumes and lentils
- Most fruits, non-starchy vegetables and carrots
Medium GI (56-69)
- Whole wheat, rye and pita bread
- Quick oats
- Brown, wild or basmati rice, couscous
High GI (70 or more)
- White bread or bagel
- Corn flakes, puffed rice, bran flakes, instant oatmeal
- Shortgrain white rice, rice pasta, macaroni and cheese from mix
- Russet potato, pumpkin
- Pretzels, rice cakes, popcorn, saltine crackers
- melons and pineapple
A glance at this list and you’d be forgiven for thinking it’s all ok. However, what is not mentioned on such a list is that simple sugars such as fructose have a GI score of 11 and can therefore be considered to be “healthy” and a tool to be used for weight loss. Fructose, unlike other simple sugars such as glucose (GI 100), lactose (GI 46) and maltose (GI 105) is the only natural sugar which has such a low score.
Unfortunately, nutrition is not as straightforward as other branches of chemistry where we are dealing with inanimate objects. Nutrition not only deals with the digestion of food items but also with the intricate biochemistry that is each and every human being.
Fructose is metabolised primarily by the liver and is absorbed by a different mechanism than glucose by the gut. Once fructose is absorbed, unlike other foods, it will not instigate an insulin response. Insulin is required as it is one of the main hormones responsible for appetite regulation. In other words energy released by fructose intake is not registered by the body. The final result being that dietary fructose contributes to increased energy intake and weight gain.
Obesity experts such as Dr. Lustig now believe that the rise in fructose consumption in the form of High Fructose Corn Syrup (HFCS) and agave nectar in beverages and pre-prepared foods are responsible for the current obesity and type 2 diabetes epidemics. Unfortunately, a recent ruling by the EFSA will allow beverages and food items containing only fructose as the sweetener, to claim that such products are beneficial of health.
Therefore, it is important to understand that just because an item is labelled as low-GI; it does not mean that it is low in carbohydrates or that it will help control blood glucose levels.