Our Guide to Low Glycemic Index Food

By Temma Ehrenfeld  @temmaehrenfeld
February 17, 2023
Our Guide to Low Glycemic Index Food

Don’t get caught up in the numbers. Just eat more low glycemic index food — vegetables and fewer white carb-laden foods — to control your diabetes.

When you eat carbohydrates, your blood sugar rises. It also matters what kind of carbohydrates you eat. A big baked potato can have the same effect on your body as pure table sugar — a fast, sharp spike in blood sugar and insulin. In the form of lentils, the same amount of carbs acts more slowly and has a smaller impact. 


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Low glycemic index food

Avoiding those spikes is good for your health. Even if you don’t have a blood sugar issue, choosing your carbs carefully will help you steer clear of various cancers and heart disease as well as type 2 diabetes. The glycemic index (GI) measures how much a food boosts blood sugar, comparing its effect to either table sugar or white bread. A food with a glycemic index of 100 has the same effect as table sugar (or bread). On the other hand, lentils have a GI around 30, compared to sugar.

When you look at GI tables, you’ll also see information on the glycemic index per serving. The tables are based on averages, which can include big variations. This list, for example, covers 62 foods. It’s also important to remember that GI tables are based on the reactions of people with normal blood sugar responses. If you have prediabetes or diabetes, you may experience bigger spikes. (You can also use this GI calculator to search for specific foods.)

You already know the foods that are heavy in starch. The glycemic index tables will help you realize just how starchy they are. A big baked russet potato has a GI of 111, compared to sugar, and 158 compared to bread. Sushi rice is just slightly better. 

How the low glycemic index diet works

Low glycemic index foods have a GI, compared to sugar, of 55 or less. This group includes nuts, beans, legumes, most fruits and vegetables, al dente pasta, dairy foods, and nuts.

Moderate GI foods run from 56 to 69. You’ll find corn, some kinds of rice, and small potatoes or yams and some breakfast cereals in this group.

The high glycemic index foods, those with a GI of 70 or higher, are the problem. This group includes all the “white” foods, including bread, rice cakes, bagels, most crackers, and packaged breakfast cereals.

Add in sugar in cakes and cookies and your GI will soar. 

When you’re preparing meals for a family, you can swap out white rice and potatoes for brown rice and yams, and substitute peas or pasta for corn. 

Fat and fiber tend to lower the GI of a food. In general, the more cooked or processed a food, the higher the GI. Juice has a higher GI than whole fruit, for example. Choose a whole grain over a refined grain. A sweeter, riper fruit has a higher GI than if the fruit is less ripe. Cooking can increase GI by reducing fiber, so al dente pasta has a lower GI than soft pasta.  

Learning the fine points

There are some fine points you’ll learn. Brown rice has a lower glycemic index than a potato or most white rice but isn’t necessarily a low-GI food. Depending on the rice, it may have a GI from 50 to 90, compared to sugar.

Converted long-grain rice can be healthier. Carbs with a low GI (55 or less) are digested more slowly and cause a lower and slower rise in your blood sugar.

Unless it helps make healthy eating fun, you don’t need to get too involved with the math. The main message:

  • Choose foods with a low GI, eat small amounts of the foods in the middle, and save high GI foods for treats.
  • Meats and fats don’t have a GI because they do not contain carbohydrates.
  • To lower the total GI of a meal, eat less of the higher-GI foods and combine them with low-GI food.
  • Healthy fats are your friends; they add calories to fill you up and won’t add to your GI count at a meal.    

GI isn’t your only consideration. You’re looking for nutritious foods and meals that are healthy. You may feel compelled to eat more meat to make up for the missing potato. There’s some evidence, however, that a vegetarian diet is helpful for type 2 diabetes, so try not to load up on steak. Gradually move towards more beans, legumes, and vegetables. 

If you’re like most Americans, you’re eating too many starchy or sugary snack foods. The GI index is another reminder of why that’s a habit to break.


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February 17, 2023

Reviewed By:  

Christopher Nystuen, MD, MBA