The Glycemic Index, GI, can be a very handy gauge to monitor the types of carbohydrates we’re eating and their impact on our energy levels and appetites. There is even a diet that focuses on low GI foods and it’s very popular among celebrities, nutritionists and dietitians. So what is it and how can it work for us, you ask?
The Glycemic Index, or GI, is a measure of how certain foods (namely carbohydrates) affect our body’s blood sugar levels. In 1981, Dr. David Jenkins tested numerous foods and their impacts on the body’s blood sugar level for 2 hours following ingestion. The studies conducted primarily focused on diabetics, because they have to closely monitor their blood sugar and insulin levels. Foods are tested and weighted on a scale of 1-100. A GI of 100 is equivalent to glucose which has an immediate and dramatic affect on the body’s blood sugar level.
The outcome separated foods into three general GI categories:
- Low 0 – 55 (Foods: milk, yogurt, non-starchy fruits & vegetables, pasta)
- Moderate 56 – 69 (Foods: Rye bread, pizza, raisins)
- High 70+ (Foods: White bread, bagels, rye bread, white rice)
The foods with low glycemic index numbers provide a more gradual blood sugar release which makes you feel full or satisfied for a longer period of time than the foods in the “High” category. These foods are absorbed slower by the stomach and provide energy over a longer period of time. The premise for the GI diet is that by eating lower GI foods you’ll have more satisfying meals and snacks will that prevent you from craving more food unnecessary binging or snacking.
Studies have shown that people that eat low GI diets have significantly reduced risk of getting type-2 diabetes and coronary heart disease. The spike in the blood sugar levels consistent with High GI foods can cause oxidative constant energy level. In addition, to the unwanted rise and fall in energy, these spikes can also cause oxidative damage to our cardiovascular system. While High-GI foods can be helpful to restore our post-workout glucose levels in the muscles (i.e. bowl of rice after a long run), these high-GI foods can also lead to over-eating and mod swings associated with our energy levels.
Reducing the GI of foods is quite tricky. Milk chocolate actually has a low GI. Peanuts are very low. White bread is very high. Rye bread is low. So it could be tricky if you’re trying to track the GI of foods that you eat daily, without finding a very comprehensive list. Eating foods together also changes the absorption and thereby creates a combination GI which is not easily figured out. A dietician or nutritionist can assist you in formulating a GI diet and calculating the meals GI value.
So what do we do with this information? If you are a diabetic or someone that has experienced hyperglycemia you should consult your physician on the pros and cons of a GI diet. Monitoring the GI of so many foods, especially given the fact they can vary significantly within their respective categories, can be a real challenge. (Examples: Potatoes – High GI / Corn – Low GI; Cornflakes – High GI / Oatbran – Low GI). Personally, my use for the Glycemic Index is limited, but effective for me. I know that I over-snack in the afternoon, so I try to eat small low-calorie, low-GI snacks that will stave on the hunger until dinner time. Summary: Be aware of the Glycemic Index and how it fits best in your fitness plan. It’s just another tool in your fitness tool box.