If you’re one of those people who can’t stand all the counting, tracking, adding, and graphing that some diets require, you might find refuge in a simple numerical scale: the glycemic index. On the other hand, you may find it just another maddening way to complicate the simple act of eating.
The glycemic index is a measure of the quality of carbohydrate foods. It’s kind of like good carbs/bad carbs, depending on how they affect blood sugar. Although not new, it started getting a lot of publicity when the anti-carb movement took hold.
It works like this: on the glycemic index, pure glucose is arbitrarily assigned a score of 100; it doesn’t mean anything in particular; it’s just a fixed benchmark of how your blood sugar has affected about two hours after eating. Then all other foods in the index are given a number relative to glucose and its effect on blood sugar.
Foods with a low index generally break down slowly and don’t cause drastic fluctuations in blood sugar. Foods with a high index usually do. For example, green peas have an index of 39, while cornflakes have an index of 92.
Originally developed to help people, especially diabetics, control blood sugar, the index includes mostly carbohydrate foods, because protein and fat don’t have an immediate effect on blood sugar.
But assigning numbers to different foods based on their glycemic effect creates a scaled list of foods that ends up being a very useful tool for people with obesity and other health issues. This is because simply following a low-glycemic index diet tends to guide people toward healthier eating and weight loss, even when that’s not their specific goal.
Consider: Type II diabetes, as well as various types of cancer and cardiovascular disease, are highly correlated with high-index diets. There is plenty of research showing that lowering the overall glycemic index also lowers the risks of these problems.
This is because, almost by default, a low-index diet will include more fresh fruits and vegetables, more fiber, more dairy, all foods that offer essential nutrients, are more likely to be low in calories, and tend to keep the body satiated for longer. , holding off the next hunger spell. All of that generally adds up to weight loss, no matter the program.
Proponents of the index say it’s more useful than counting calories or grams of fat or carbohydrates, and actually offers a simplified approach to learning how to eat better, but some experts caution that people shouldn’t worry too much about precise numbers. Instead, they urge people to pay attention to whether the foods they eat have a low, medium, or high index.
That’s because, as with any rule, there are exceptions to the fairly consistent physiological rules that underlie the index. For example, watermelon has a fairly high glycemic index, around 75, which is even higher than table sugar. Does that make it bad for you? No. Because despite its high index, watermelon actually has a fairly low glycemic load. That’s a measure based on how much food you would actually eat, not just some arbitrary amount used in tests, like with the index.
The glycemic load of a food can be determined by using the food’s glycemic index, divided by 100, and multiplied by the available carbohydrates you would eat. With most foods, a low index is consistent with a low load, but there are rare exceptions. Of course, to find them, you’d have to do a lot of math again, and that’s not the way people normally eat.
That’s why doctors and nutrition experts encourage people trying to develop a healthy diet to avoid getting caught up in the numbers game and take a more general look at the foods on the index, leaning toward those that are found at the lower end. Anything above 70 is considered high, 55 to 69 is medium, and below 55 are low glycemic index foods.
And look at what’s in those groups: High-index foods include most breakfast cereals, white bread and other processed baked goods, most potatoes, ice cream, candy, and table sugar, your real Atkins nightmare.
The lowest index foods include cherries, grapefruit, broccoli, vegetables like lentils and beans, most whole-grain baked goods, and most dairy products. So even without counting calories or keeping track of specific index numbers, you can see that targeting your diet toward the lower end of the index is sure to do you good.
We like to encourage patients to think of the glycemic index and glycemic load as two more tools that can be helpful in developing healthier thinking and planning about eating habits.
One last thing to remember: There is no list of standardized glycemic indices, and most indices include brand-name items that people buy on a typical shopping trip, as well as more generic items like vegetables and fruits. This is one of the most useful aspects of lists, but only if you get one that is related to where you live.
If your average Southwest Florida resident looked at an index created in Australia, it wouldn’t help much, because really, when was the last time you had a couple of Golden Pikelets with a nice glass of Milo?
THROUGH THE FORCES AND THE FRUITS
Fruits tend to be high on the glycemic index, so I recommend that people take their fruit with a meal or with a protein such as cottage cheese or regular cheese. These protein sources help mitigate the glycemic effect of the fruit. Don’t let a high index number keep you from your daily apple.
