Prediabetes: Nutrition Basics

What is prediabetes?

Prediabetes refers to having blood glucose (sugar) levels that are high, but not yet high enough to be diagnosed with type II diabetes. Prediabetes can develop into type II diabetes. You can learn about diabetes here.

Glucose (sugar) is the primary source of energy our body uses, and it primarily comes from food and drinks. Insulin is a hormone made by an organ in your body called the pancreas, which controls your body’s ability to use and store glucose. After we eat, glucose from the food enters our blood. Insulin allows glucose to leave blood and enter the cells. This keeps blood glucose levels in a normal range. If our body does not make enough insulin or does not respond to insulin as well as it should (also called insulin resistance), blood glucose levels become high.

How is prediabetes diagnosed?

Prediabetes can be diagnosed through blood tests that measure blood sugar levels. Doctors often use the Hemoglobin A1c test which measures your average blood sugar over 3 months. They may also use a fasting blood sugar test, which can be done after you haven’t eaten for at least 8 hours or overnight.

Result	Hemoglobin A1c	Fasting blood sugar
Normal	<5.7%	<100mg/dL
Prediabetes	5.7%-6.4%	100-125mg/dL
Diabetes	>6.5%	>126mg/dL

Prediabetes is reversible with the help of lifestyle changes like adopting healthier eating habits and increasing physical activity, and, if recommended by your doctor, with the support of medication.

What do I need to know about insulin and carbohydrates?

The insulin level in your blood goes up after you eat. It goes up the most after you eat or drink something that is high in carbohydrates. Carbohydrates are found in grains (such as bread, pasta, rice, and cereal), most snack foods (such as chips, cookies, and candy), sugary drinks such as soda and juice, and in fruits and vegetables.

Are all carbohydrates the same?

No. Even if you eat two foods that have the same amount of carbohydrates, they may have a different effect on your insulin level. This effect has a lot to do with the type of carbohydrate in the food. Carbohydrate foods with fiber such as whole grains, fruits, and vegetables, are also called “low glycemic index foods” or “complex carbohydrates” meaning they cause less of an increase in blood sugar and insulin levels. Carbohydrate foods that are sugary or refined (such as soda, juice, white bread, and white rice), also called “simple carbohydrates” or “high glycemic index foods” can cause insulin levels to spike higher. Foods and drinks that cause a big spike in blood sugar and insulin levels are not very filling, which means you may feel hungry shortly after eating them. This is one reason dietitians recommend choosing high-fiber, low-sugar foods.

If I have prediabetes, do I need to buy special foods?

No. You don’t need to go out of your way to buy special foods. Just like with any healthy eating plan, your meals should include a balance of vegetables, fruits, whole grains, plant-based protein, lean meats and fish, dairy, and healthy fats. Most foods fit into a healthy eating plan for prediabetes, but you should read food labels to help you pick out the healthier options. Look for high–fiber grains such as brown rice, whole–wheat pasta, and whole–wheat bread rather than low–fiber grains such as white rice, pasta, or white bread.

Don’t be fooled by fat–free treats. They usually have a lot of added sugar. Also, some sugar–free foods (such as baked goods) are made with refined grains such as white flour which can raise your insulin levels the same way that sugar can. Other sugar–free foods are carbohydrate-free. These foods, sweetened with artificial sweeteners, may be a good alternative if they don’t upset your stomach. There is currently no scientific data that suggests moderate amounts of artificial sweeteners are harmful to our health. It is important to remember that these foods often lack other necessary nutrients. Try to stick to the most natural, whole form of each food (ie, lemon sliced in water instead of diet lemonade).

Try these healthy food “swaps” if you’re looking for alternatives to refined carbohydrates.

Instead of:

• Sweetened juice, canned fruit in heavy syrup, or sweetened applesauce
• Starchy vegetables such as potatoes, corn, and peas
• Refined grains made with white flour such as white bread and pasta, bagels, or white rice
• Sugared cereals such as those that are frosted, contain marshmallows, or are sweet and fruity, and other sweetened grains such as cereal bars, breakfast pastries, and donuts
• Sugary drinks such as soda or juice
• Sugary foods such as cookies, cakes, and candy
• Snacks such as potato chips and tortilla chips

Choose:

• Fresh fruits or frozen/canned fruit without added sugar, or unsweetened applesauce
• Non–starchy vegetables such as broccoli, spinach, tomato, mushroom, peppers, and carrots
• Whole grains such as whole wheat pasta, brown rice, oats, quinoa, and whole wheat bread
• High fiber cereals such as shredded wheat, and bran flakes. (Look for cereals that have at least 5 grams of fiber per serving or sprinkle ½ cup of bran cereal or unprocessed bran on a low–fiber cereal to increase the fiber)
• Water or seltzer, flavored with fruit if desired, unsweetened iced tea
• High fiber baked goods made from whole wheat flour and oats
• Crackers and snacks with fiber such as woven whole wheat crackers, whole grain crispbread, or popcorn

Should I cut out carbohydrates?

No! Carbs (carbohydrates) give your body energy. Some people have heard that eating carbs will make them gain weight, but carbs are essential to appropriately fuel your body. Many other important nutrients like vitamins and minerals come from food with carbohydrates, so avoid cutting out carbs completely If you think you’re eating more carbohydrates than your body needs, try to check if the carbohydrate foods are taking up more than ¼ of your plate and then reduce your serving size based on your hunger and fullness cues if they are.

What about foods that have fats and proteins in them?

Protein foods such as beans, hummus, nuts, nut/seed butter, tofu, eggs, fish, chicken, meat and vegetarian meat substitutes, and fats such as olive oil, nuts, and avocado are an important part of a prediabetes–friendly eating plan. Combining foods that contain protein and/or fat with a carbohydrate will help to slow down the absorption of the carbohydrate and keep insulin levels low. For example, instead of plain rice, have rice with beans and a little avocado.

Keep in mind that some fats have more nutritional benefits than others. Heart-healthy fats, also referred to as unsaturated fats, are found in olive oil, canola oil, nuts, avocados, and fish. Try to incorporate healthy unsaturated fats and proteins as alternatives to butter, margarine, creamy sauces or dressings, and red meat.

Do I need to follow a diet that is extra high in protein?

No. Extremely high protein diets (such as the Atkins, Paleo, or Ketogenic diet) are not a good option for teens/young adults because they can be low in some important nutrients such as fiber, B vitamins, and vitamin C, and they can stress your kidneys. It’s also important to remember that even if you limit your carbohydrate intake, overeating fat or protein can cause unintentional weight gain. You should aim to eat a balanced diet that contains protein, high-fiber carbohydrates, and some fat.

Should I follow a low glycemic diet?

Glycemic index is a term used to describe how a food affects blood sugar. The higher a food raises blood sugar, the higher the glycemic index. High–fiber carbs have a lower glycemic index than sugary or refined carbs. Combining a carbohydrate food with another food (such as a protein) can lower the glycemic index because it allows your body to absorb the carbohydrate more slowly. For example, if you have a cupcake immediately after a meal it will not raise your blood sugar as high as it would if you ate the cupcake on its own an hour or two after a meal. Having prediabetes doesn’t mean you have to follow a low-glycemic diet, but keeping in mind the equation of protein+fiber will be helpful when planning meals and snacks.

What fruits and vegetables are good options when I have prediabetes?

Vegetables such as asparagus, broccoli, carrots, cauliflower, celery, cucumber, green beans, spinach, tomatoes, and zucchini and fruits such as apples, berries, grapes, oranges, peaches, and plums have a low glycemic index.

Fruits and vegetables with more sugar or starch, such as dried fruit, tropical fruit, corn, potatoes, squash, and peas, have a higher glycemic index.

If I choose the right foods, do I still need to pay attention to portion sizes?

Yes; in addition to what you eat, how much you eat also affects your insulin levels. For example, your insulin will go up much more if you have 3 cups of pasta than if you have 1 cup of pasta, even if the pasta is whole grain. This means it’s usually better to have several small meals and snacks throughout the day than it is to have a few really big meals. Having more frequent smaller meals and snacks will keep your insulin level lower and help you avoid big spikes in blood sugar levels throughout the day.

Is it important for me to exercise?

Yes! It’s really important that young people with prediabetes are physically active, because exercise brings down insulin levels, can help with weight management, is important for cardiovascular health, and can help improve mood. Exercise can be especially helpful in lowering insulin and blood sugar levels directly after a meal. So, if possible, go for a walk or find an enjoyable way to move your body after you eat a meal. Any activity helps, so find a type of movement that you enjoy. If you aren’t already exercising, start slowly, and build up to your fitness goals. If you currently only exercise occasionally, try to make it more regular. Work towards increasing your physical activity to at least 5 days per week for 60 minutes per day.

Do I have to lose weight?

Weight loss is often recommended to people with prediabetes. However, you do not necessarily need to lose weight to improve your blood sugar. Some recent research has shown that health behaviors (eating balanced meals, exercising, not smoking, etc) are better indicators of long-term health than how much you weigh. So while some weight loss can improve insulin sensitivity, weight management should be approached very carefully with guidance from a medical provider and dietitian to support healthy growth and development.

Can’t I just take medication to lower my blood sugar?

There are medications that can help manage blood sugar, though changes to eating habits and exercise are still needed to support health in the long term. The goal of medication would be to aid in lowering your blood sugar while you also work on healthy habits. Often times, metformin (an oral medication used for people with diabetes) can be prescribed to people with prediabetes, but it’s important to talk to your health care provider so you can make the best decision for you and your health.

I already have PCOS, how is that different than prediabetes?

The difference between Polycystic Ovary Syndrome (PCOS) and prediabetes is that PCOS  is a hormonal imbalance and often has other side effects like irregular periods, acne and excess hair growth. Insulin resistance is also common in those with PCOS, which means someone with PCOS may have increased blood glucose levels and an increased risk of developing prediabetes. This means that the same exercise and diet changes that are recommended for someone with prediabetes will also be helpful for someone with PCOS. You can read more about these recommendations in our PCOS guides.

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