The Glycemic Index Diet for Dummies - Meri Raffetto [18]
The glycemic index actually simplifies that technical mumbo jumbo a bit. Instead of focusing on complex versus simple carbs to find your best food choices for weight loss, you can focus on choosing low-glycemic foods that have a high nutrient content. Low-glycemic foods are therefore the new "friendly" carbs, and high-glycemic foods are the new "foes."
Most people think of sugar, sweets, or white flour as simple carbohydrates that make for unhealthy choices. However, the issue isn't quite that black and white. Consider the case of white flour. Often mistakenly lumped in the simple-sugars category, white flour is actually a complex carbohydrate, and complex carbs are typically labeled as "good carbs." So not all complex carbs are necessarily the healthiest choices. White flour is an example of a high-glycemic "foe," spiking the blood sugar much higher and faster than its whole-wheat counterpart (a low-glycemic "friendly" carb).
You can't tell what food is friend or foe just by looking. Instead, the food must undergo scientific testing to determine how it responds in the body. Keep reading to find out how to know which foods are friends and which foods are foes.
Measuring a Food's Glycemic Index
What makes a food low- or high-glycemic? First off, only foods that contain carbohydrates can be considered low-, medium-, or high-glycemic. Foods such as meats, poultry, fish, and fats (think oil and butter), don't contain carbohydrates, which means you have to rely on your nutrition know-how to determine what kinds and how much of them to eat.
The glycemic level of a food measures how fast that food is likely to raise your blood sugar. A food that raises your blood sugar quickly is considered high-glycemic, and a food that raises it slowly is considered low-glycemic. Foods that fall somewhere in the middle have (you guessed it) a medium glycemic level.
Basing food choices solely on the glycemic index can be dangerous because that means you're only looking at one aspect of food and ignoring other important ones (such as calories, amount and type of fat, and vitamin and mineral content). Many people think that whole grains, fruits, and vegetables naturally fall into the low-glycemic category. Although this is true much of the time, it isn't always the case. Some of these foods actually have a high glycemic index, and many nonnutritious foods, like certain candies and chips, have a low gcemic index. Don't simply take the road of "all low-glycemic foods are okay, so I can eat as much of them as I want." That's what happened during the lowfat craze of the '80s and '90s. People started eating fat-free everything, even if it meant higher sugar and calorie content. The same trend is emerging with low-glycemic foods; don't give in to it!
The glycemic index is a great tool, but you also need to make sure you're eating nutritious foods most of the time and not filling up on candy and chips just because they're low-glycemic. Don't toss everything you know about good nutrition out the window.
The next sections help you understand how scientists calculate the glycemic index and explain a few of the resulting caveats.
Comparing foods to pure sugar with human help
Because the glycemic index deals with your blood sugar's reaction to various foods, determining a particular food's glycemic index calls for the help of human test subjects. First, researchers feed 50 grams of available carbohydrates (that's total carbohydrate minus fiber) to ten or more volunteers to test how the food raises blood sugar levels at different intervals over a two-hour period after it's consumed. They then plot these changes in blood sugar on a graph and compare the volunteers' responses to the test carbohydrate to their responses to the same amount of pure sugar or white bread. The average blood sugar response