Diabetes Diet

January 7, 2025

This page was reviewed under our medical and editorial policy by Shaelyn Gurzick, RDN, CDCES, CNSC, clinical dietitian and diabetes educator, Department of Diabetes, Endocrinology & Metabolism, City of Hope^® Cancer Center Orange County

Diabetes is a condition in which the body is unable to regulate levels of sugar (glucose) in the blood. Because of this, it has trouble turning food into energy.

Glucose is mainly from food and is the body’s main energy source. Normally, a hormone called insulin helps people get glucose from the bloodstream into cells. However, if there is not enough insulin or the body is unable to use it appropriately, glucose builds up, causing high blood sugar levels.

There are different types of diabetes.

Type 1 diabetes: The body does not make insulin at all. The likely reason is an autoimmune reaction that stops insulin production in the pancreas. Without insulin, glucose builds up, leading to high blood sugar levels.

Type 2 diabetes: The body is unable to use insulin well, leading to abnormal levels of glucose in the blood.

Gestational diabetes: When a woman who has never had diabetes develops the condition during pregnancy, it is called gestational diabetes. Typically, blood sugar levels go back to normal after pregnancy, but the baby and mother have a higher risk for developing type 2 diabetes and obesity in the future.

Prediabetes: This occurs when blood sugar levels are higher than normal but not yet in the diabetes range. Prediabetes may be preventable with changes in eating and exercise habits, but without these changes, it may progress to type 2 diabetes.

Other types: Less common types of diabetes may also develop, many of which require dietary and lifestyle changes.

Food and Blood Sugar Levels

The body breaks down carbohydrates (carbs) that are eaten into glucose for energy. Foods like bread, pasta, rice, fruits and sugary snacks are particularly high in carbs, so eating them tends to cause blood sugar levels to rise.

Once carbs are broken down into glucose, it enters the bloodstream. How fast this happens depends on the type of carbohydrates someone eats, the amount eaten, the time they are eaten and sometimes what they are eaten with.

Carbohydrates are categorized into three main types. Each type affects blood sugar levels differently.

Simple carbohydrates (sugars): These are found in some whole foods like fruit and milk, or they may be added to processed foods like soda, cookies and candy. These carbohydrates digest quickly, causing rapid spikes in blood sugar.

Complex carbohydrates (starches): These are found in foods like grains, beans and starchy vegetables. They break down slowly, leading to a gradual rise in blood glucose.

Fiber: This is found in plant-based foods, and most is indigestible, so it does not raise blood sugar. Instead, it contributes to steady glucose levels.

For people with diabetes or insulin resistance, tracking carbohydrates during the day is crucial to ensuring blood sugar levels stay stable. 

What Is a Diabetes Diet?

The goal of a diabetes diet is to help manage blood sugar levels by eating at the appropriate times, and eating the appropriate foods in the proper amounts. This may help regulate insulin needs and prevent blood sugar spikes.

A diabetes diet varies for each individual. No single plan works for everyone. Factors like medications, weight, exercise habits and other health conditions all play a role in figuring out the most appropriate diet. It is also important to consider food preferences, available time for cooking and budget.

Good Foods for Diabetes

To manage diabetes, it is essential to focus on a variety of healthy foods that help maintain stable blood sugar levels. Here are some recommended options:

• Fruits that are fresh, frozen or canned with no added sugar like apples, oranges, blueberries, cherries, pears, plums, grapefruit and peaches
• Non-starchy vegetables like green beans, eggplant, carrots, cauliflower, mushrooms, tomatoes, spinach, onions and peppers
• Whole grains like whole wheat, brown rice, quinoa, oats, barley, popcorn, wild rice, bulgur and sorghum
• Lean proteins like chicken, turkey, fish, eggs, cheese, nuts, beans, lentils, tofu and lean cuts of pork, lamb and beef
• Nonfat or low-fat dairy like milk, yogurt and cheese with no added sugar
• Healthy fats such as olive, canola, avocado, and soybean oils, avocados, olives, and nuts

Foods to Limit for Diabetes

Certain foods and drinks should be avoided or limited to control blood sugar levels. Items that may cause blood sugar spikes include:

• Starchy vegetables like peas, potatoes, corn, yams, and plantains in large amounts or with added fats or sugars (such as maple-roasted yams)
• Sugary foods like candy, cookies, cake and ice cream
• Sweetened beverages such as soda, fruit juice, sports or energy drinks and alcohol
• Refined grains like pasta, white bread, white rice, breakfast cereals and tortillas
• Fried foods and those high in saturated or trans fats, like French fries, fried chicken, pastries, cakes, and other baked goods
• Foods that are high in sodium

Portion Size and Food Preparation

It is important to pay attention to portion size, or the amount of food selected to eat at one time, during meals and snacks. This is especially important when eating out, as restaurant entrees may be 3 or 4 times larger than a healthy portion size. One way to deal with this is to ask the restaurant to wrap up half the meal to eat later.

At home, being intentional about measuring out snacks and meal servings is key to sticking with healthy portion sizes. The U.S. Centers for Disease Control and Prevention suggests using the size of your hand to estimate portion sizes. Some examples of portion sizes include:

• 3 ounces of meat, fish or poultry: palm of hand
• 1 ounce of cheese or meat: thumb
• 1 cup or 1 medium fruit: fist
• 1-2 ounces of nuts or pretzels: cupped hand

Portion sizing is a way to gauge how much to eat. Serving sizes on food products are a bit different. It’s a measure from the manufacturer of what most people are likely to eat at one sitting and the nutrition facts for that serving.

Preparing food at home provides the greatest opportunity for diabetes-friendly meals. Choose lean cuts of meat, poultry or fish, and remove any skin or visible fat. Instead of frying, bake, roast, broil, grill or boil instead. When frying is necessary, use healthy oils like olive oil.

What Is the Glycemic Index?

The glycemic index (GI) measures how quickly carbohydrate-containing foods boost blood sugar levels. Low GI foods cause a slower, gradual rise in blood sugar, while high GI foods trigger a rapid increase.

The GI scale ranges from 0 to 100, with 100 being pure glucose. Focusing on low GI foods, which help maintain steady blood sugar levels, is a strategy to manage diabetes. Being aware of a food’s GI number, alongside carbohydrate counting, may also support weight management.

Glycemic Index Chart

Choosing more of the high GI foods can make it harder to manage diabetes. Choosing low GI foods most of the time may help manage diabetes.

Keep in mind that fats, oils and meats do not have a GI but may still affect blood sugar levels.

How to Use the Glycemic Index in a Diabetes Diet

Though the glycemic index is limited to carbohydrate foods, GI is a useful tool in managing a diabetes diet. Choosing low GI foods like whole grains, legumes and non-starchy vegetables may help maintain stable blood sugar levels. Not all meals contain only low GI foods, however. Balancing high GI foods with lower GI options may bring down the overall impact on blood sugar (glycemic load). For example, pairing white bread with a salad or protein may moderate its glycemic effect.

In addition to the GI, the glycemic load (GL) offers a more exact way to understand a food’s impact on blood sugar. While GI measures how quickly a type of carbohydrate raises blood sugar, GL considers how much of the carbohydrate a person would eat in a serving. For example, watermelon has a high GI, but a low GL because it is mostly fiber and water — and not much sugar in one serving. Foods with a low GL tend to also have a low GI, while those with a medium or high GL may have varying GI levels, ranging from low to high.

GI and GL may be difficult to use because they are not found on food labels, but they are useful tools to understand how different foods affect blood sugar levels, hunger, insulin needs and fat storage in the body.