Understanding and Managing Blood Sugar

Low glycemic foods good for blood sugar management

/ Author:  / Reviewed by: Robert Carlson, M.D

Carbohydrates include some of the tastiest foods out there, like pasta and pie. But they also get a bad rap when it comes to their nutritional contributions. Do they deserve it?  Well, yes and no. The problem is that all carbs are not created equal, just as not all proteins and all fats are equal. Understanding the differences in these macronutrients, which make up all the foods we eat, can help you learn how to make healthier diet choices.

Many people realize that protein is good, but that doesn't mean you should eat a pound of bacon every day. Healthier sources of protein, with less sodium and less fat, include fish and chicken.

We need fat in our diet too, and researchers are trying to learn more about what the differences are between saturated and unsaturated fats to guide dietary advice.

When it comes to making healthy choices about carbohydrates, one of the most helpful things to understand is the food's glycemic index.

What's a Glycemic Index?

A food's glycemic index is a score that tells you how much a certain food will increase your blood sugar, compared to how much straight sugar (glucose) will increase your blood sugar.

A food with a high score will increase your blood sugar faster and higher than a food that has a low score.

For example, hummus has a glycemic index of 6. That means it increases your blood sugar only 6 percent of what pure glucose would. Grapefruit, with a glycemic index of 25, increases your blood sugar 25 percent of what straight sugar would.

On the other hand, a plain white bread baguette has a glycemic index of 95. By increasing your blood sugar 95 percent as much as glucose would, a baguette by itself is almost like eating pure sugar as far as your body's blood sugar response is concerned.

Another high glycemic food is typical white rice, which has a glycemic index of about 89. Choosing foods with lower glycemic index numbers, or pairing a high glycemic food with a low glycemic food to balance it, can help keep your blood sugar levels in check.

How Does "Blood Sugar" Work?

Your blood sugar level is one indicator of your metabolic health. Although blood sugar provides the main source of energy in your body, having levels that are too high can lead you to develop diabetes over time.

Blood sugar levels come from the sugars and starches (carbohydrates) contained in food that your body breaks down. As the sugars move through the blood, a hormone called insulin helps push the sugar from the blood into the body's cells so the body can use it.

However, if your blood sugar spikes too often and too high, you can develop insulin resistance. In this condition, the cells don't respond properly to the insulin, which means they don't gain the beneficial energy from sugar in the blood.

Meanwhile, during insulin resistance, blood sugar levels will increase, and the liver cannot properly regulate glucose levels in the blood.

Having blood sugar levels that are too high is called hyperglycemia, which can lead to fatigue, blurred vision, extreme thirst and needing to urinate a lot.

The opposite of hyperglycemia is hypoglycemia, a condition in which blood sugar levels are too low. Diabetics with hypoglycemia become sweaty, dizzy, hungry and shaky. It can be very serious if not treated.

How Do I Pick Low Glycemic Foods?

Various websites provide information on the glycemic index of different foods, including the "Glycemic index and glycemic load for 100+ foods" available on the Harvard Health website.

A low glycemic index is generally considered a number at about 55 or below. A high glycemic index is typically anything at 70 or higher.

In general, foods made with higher levels of processed carbohydrates and/or high amounts of sugar will have a higher glycemic load. Having a higher load does not mean you have to avoid that food completely.

However, you should limit how often you eat high glycemic foods on their own, and you should try to eat low glycemic foods at the same time.

For example, rice cakes have a glycemic index of 82, and soda crackers have one of 74. But pairing these crackers with hummus, which has a glycemic index of 6, can help prevent your blood sugar from spiking quickly.

Just because a food is a fruit or vegetable does not mean it will have a low glycemic index. White potatoes have a high glycemic index of 82, and sweet potatoes are only a little lower, at 70. Carrots, meanwhile, are lower, at 35, and green peas are in the middle, at 51.

Even though fruits have natural sugars, there are many fruits that have middle range or low glycemic loads, such as apples at 39, oranges at 40, and pears at 38. Strawberries have a glycemic index of 40, and blueberries have an index of 53. Grapefruit has one of the lowest glycemic indexes of 25.

High glycemic fruits include, among others, watermelons at 72, and bananas are a medium glycemic fruit at 62.

One way to help control your blood sugar is to make swaps of higher glycemic foods for similar ones that have a lower glycemic index. You could eat brown rice instead of white rice, or steel-cut oats instead of instant oatmeal.

Bran flakes have a lower glycemic index than corn flakes, and whole grain bread is a better pick than white bread.

If you are craving a piece of sugary white cake, however, try to have a food with fat or protein at the same time to slow down the blood sugar rush. Low sugar ice cream may provide the perfect pairing.

Reviewed by: 
Review Date: 
February 19, 2013
Last Updated:
January 7, 2014