How many carbs should you eat if you are prediabetic

When you receive a diagnosis like diabetes, the first thing your care team will probably want to talk about is your diet-and specifically, how many carbohydrates you're getting on a daily basis. That's because carbohydrates play an outsized role in the management of diabetes, as their breakdown in your digestive system causes your blood sugar to rise. And, by now, you probably know that controlling your diabetes is directly related to controlling your blood sugar.

So even if you haven't spent much time thinking about carbs in the past, now you might be wondering what, exactly, carbs are, in addition to wondering which foods have carbs and how many grams you should aim to eat daily.

But before you settle on a number or stop eating carbs altogether, educate yourself about different types of carbs and how they affect your diabetes diet plan. Once you're a little more familiar with where you'll find carbohydrates and how they fit into a diabetes-management plan, then you'll be able to zero in on the right carb count for you.

Nutrition basics for diabetes-friendly eating

Carb counting goes hand-in-hand with calorie counting. So before getting into the nitty-gritty of counting carbohydrates, it's helpful to do a quick refresher on what makes up a calorie. Calories come from three nutrients: carbohydrate, protein and fat, which are also known as macronutrients. Alcohol also has calories. In contrast, vitamins and minerals are micronutrients and don't have any calories. The foods we eat are made up of varying amounts of carbohydrates, protein and fat. For example, a potato is mostly carbohydrate with a small amount of protein. Top it with sour cream and you've added calories from fat. A piece of skinless chicken breast-like the one in the recipe for Chicken Burrito Bowls above-contains mostly protein, a small amount of fat and no carbohydrate. How the chicken is prepared can add other nutrients and calories. For example, breading chicken will add more carbohydrates; frying it will add more fat.

What foods contain carbs?

There are three types of carbohydrates: sugar, starch and fiber. If you're counting carbohydrates, you want to pay attention to the Total Carbohydrates on the nutrition label, which is the sum of all three types.

You probably already know that there are carbohydrates in a slice of bread or a bowl of pasta. But here are some other foods that mostly derive calories from carbohydrates (some also contain protein and fat).

• Grains: Bread, cereal, pasta, rice, tortillas, crackers, oats, whole grains
• Legumes: Lentils, beans, peas
• Starchy vegetables: Potatoes, corn
• Nonstarchy vegetables: All other vegetables (e.g., green beans, tomatoes, lettuce, carrots, asparagus, cauliflower, broccoli, spinach, kale, beets, etc.)
• Fruit: All kinds
• Dairy products: Milk, yogurt
• Sugary beverages: Regular soda, fruit juice
• Sweets: Ice cream, candy, baked goods

What's the connection between carbs, insulin and blood sugar?

You might be wondering why your care team is so concerned about carb counting, and why it's important to space out the carbs you eat over the day. Here's why: When you eat foods with carbohydrates, the carbohydrate is broken down into glucose (sugar), which enters your bloodstream, raising the amount of sugar in your blood. This signals the pancreas to release insulin. Insulin then takes the sugar from your blood to your cells to be used for energy. Subsequently, the amount of sugar in your blood comes down. The next time you eat, this process happens again.

If you have diabetes, your body doesn't use insulin properly, making it hard for your body to regulate the amount of sugar in your bloodstream. Because carbohydrates cause your blood sugar to rise, controlling your intake of carbohydrates helps control your blood sugar as well.

But here's a little tip: While there are three types of carbohydrates-sugar, fiber and starch-they are not all digested the same.

Nonstarchy vegetables contain mostly fiber and little to no sugar, so they don't raise your blood sugar very high and therefore, not as much insulin needs to be released. (So pile those nonstarchy vegetables on your plate!)

In contrast, fruit juice, soda and refined grains (e.g., white pasta, rice or bread), contain little to no fiber, so they spike your blood sugar and more insulin is released. The glycemic index further explains the effect that different foods have on your blood sugar level, but eating a healthy, low-carb, vegetable-packed diet is a good place to start.

Why should I eat foods that have carbs?

Lemon-Herb Salmon with Caponata & Farro

While it might seem as though drastically reducing or eliminating carbohydrates from your diet would be a good idea if you have diabetes, it's not a realistic-or healthy-goal. Carbs are your body's preferred source of energy. Unlike protein and fat, which are digested more slowly, carbohydrates provide quickly available energy. Fruits, vegetables and whole grains, which are all carbohydrates, also provide essential calories (energy), vitamins, minerals and antioxidants that are important for good health. A diet rich in fruits, vegetables and whole grains is associated with maintaining a healthy weight, having a healthy heart, reducing risk of cancer, keeping blood pressure and blood sugar levels healthy and living longer.

Plus, fruits, vegetables and whole grains are also full of fiber, which is the indigestible part of plant foods. Most fiber is passed through the intestines and not digested. Because it's not digested, fiber does not raise blood glucose like sugar and starches. Studies show that people with diabetes who eat enough fiber are better able to control their blood sugar than those who eat less fiber.

Fiber also lowers cholesterol, keeps your bowel movements regular and keeps you full longer. The current daily recommendation for fiber is to eat 25-35 grams per day. Most Americans eat half this amount. Look for recipes prioritizing vegetables, whole grains and lean protein, like the Lemon-Herb Salmon with Caponata and Farro above, which provides a good mix of fiber, protein and carbohydrates.

What percentage of calories should come from carbs?

There is no one-size-fits-all diet plan for people with diabetes. It's important to work with your doctor and dietitian to figure out what percent of carbohydrates, fat and protein you should be eating each day.

The Dietary Guidelines for Americans recommend that 45-65 percent of daily calories come from carbohydrates. However, some studies suggest that if you have diabetes, eating less than that may be beneficial for two reasons. First, the fewer carbohydrates you eat, the lower your blood sugar levels. Second, eating fewer carbohydrates equates to eating fewer calories (if you don't replace the carbohydrates with calories from protein or fat) and eating fewer calories results in weight loss. Losing weight is associated with better blood sugar control and fewer health complications from diabetes.

Joslin Diabetes Center, a Harvard Medical School affiliate and diabetes clinic, recommends sticking closer to 40 percent of calories coming from carbohydrates and 20-30 percent coming from protein to promote weight loss.

How to count carbs

Keeping track of carbohydrates is key if you're following a diabetes-friendly diet, but if you've never had to count carbs, you might be wondering where to start. There are 4 calories in 1 gram of carbohydrate, so you have to convert calories of carbohydrates into grams to know how many grams to consume each day. First, sit down with a dietitian to figure out your daily calorie needs. If, for example, you need 2,000 calories per day and are aiming for 40 percent from carbohydrates, you need to take 40 percent of 2,000:

0.4 x 2,000 = 800 calories

Then divide by 4, since there are 4 calories in 1 gram of carbohydrate:

800 / 4 = 200 grams

You'd want to aim for 200 grams of carbohydrates for the day. Be sure to space them evenly throughout the day in your meals and snacks. It's also important to pair carbohydrates with protein and fat to slow digestion, prevent a blood sugar spike and keep you feeling fuller longer. Work with your health care provider to figure out how to balance carb intake with your medications, insulin and exercise routine-all will affect how and when you eat carbs.

Why choose carbohydrates with fiber, rather than sugar?

Remember that carbohydrates can be further broken down into fiber and sugar. Research shows Americans eat too much added sugar (about 22 teaspoons a day, which translates to about 350 calories!) and not enough fruits, vegetables, whole grains and low-fat dairy foods. Added sugar is anything that's not plain dairy or fruit. The American Heart Association recommends women eat less than 24 grams of added sugar per day (6 teaspoons) and men consume no more than 36 grams per day (9 teaspoons).

Instead, try to prioritize carbohydrates that provide fiber. Aim to get 25-35 grams of feel-full fiber each day. Focus on the quality of carbs you eat, aiming to make half your plate nonstarchy vegetables, a quarter of your plate whole grains and a quarter of your plate protein at most meals. Reduce your consumption of low-fiber, sugary foods and beverages, including desserts, muffins, soda, sugary coffee beverages, fruit juice, ice cream and baked goods, which add carbs without much nutrition.

The above recipe for Strawberry & Tuna Spinach Salad provides 20 grams of protein and 10 grams of fiber for a healthy, satisfying meal that's also diabetes-friendly.

What's the deal with low-carb diets and diabetes?

Low-carb diets are often trending, and if you have diabetes, it might be tempting to try it out. But be aware: It's difficult to study low-carb diets because there is no consensus on how many carbs a low-carb diet contains. In general, it's less than 45 percent of calories from carbs, but could be as low as 10 percent, like in the ketogenic diet.

If you're eating for diabetes, you also have to consider what's being studied-the effect of a low-carb diet on blood sugar control? Insulin sensitivity? Weight loss? A1C? Cholesterol levels?

In the short term, low-carb diets lead to weight loss and improved blood sugar control. However, one study found that after one year, there was no difference in weight lost or A1C levels between those who ate a low-carb diet and those who ate a low-fat diet.

Here's something else to think about: When people eat low-carb diets, they tend to eat more fat and protein. Choosing saturated fats like red meat and dairy can raise cholesterol levels. So while you might improve your blood sugars eating low-carb, you could worsen your heart health in the process.

What about the ketogenic diet and diabetes?

Less than 5-10 percent of calories come from carbohydrates on the ketogenic diet (about 20-50 grams/day). While this diet has been around for many years for seizure control in patients with epilepsy, it has gained popularity in recent years because its very low carb intake results in rapid weight loss. When your intake of carbohydrates is extremely low, the body uses fat (ketones) for energy instead of carbohydrates. While this sounds good in theory, it's difficult to maintain ketosis long-term. Some recent studies show successful weight loss and lowered A1C levels in those following a ketogenic diet, but the studies are small, have limitations and lack long-term research.

The bottom line on low-carb and keto: you don't need to eat a very low-carb diet to see improvements in blood sugar control or lose weight. The most effective diet is the one you can stick with for the long term. Most people can't sustain eating just 5-10 percent of their calories from carbohydrates, as is required on the ketogenic diet. However, you may be able to sustain 40-45 percent of your calories from carbs, which is the lower end of the recommended 45-65 percent. Talk to your health care provider to come up with a plan before you try anything drastic.

What to know about weight loss and diabetes

Vegetable Weight-Loss Soup Recipe

Research shows that losing weight can help you hit your blood glucose targets and control or slow progression of your prediabetes or type 2 diabetes. Studies haven't shown a low-carb diet to be more effective than a low-fat diet for long-term weight loss and maintenance. But you do need to maintain a calorie deficit if you want to lose weight.

Two large, multi-year studies funded by National Institutes of Health-the Diabetes Prevention Program (DPP) in prediabetes and Look AHEAD (Action for Health in Diabetes) in type 2 diabetes-used a lower-calorie eating plan and encouraged people to be more aware of their fat consumption by counting fat grams and calories. They didn't focus on carbs. Both studies showed that people who lost weight-and kept it off-experienced numerous health benefits over the years. Both studies also encouraged physical activity almost every day.

Joslin also recommends 60-90 minutes of moderate-intensity physical activity most days of the week. This includes both cardio and strength training. Muscle burns calories, so if you're only doing cardio, consider upping the resistance training to get more calorie burn throughout the day.

Here's the bottom line on weight loss and diabetes: You can lose weight eating low-carb or low-fat, as long as you're eating fewer calories. But the hard part is keeping it off. So work toward creating a healthy lifestyle that you can maintain for the long term. This usually involves being physically active most days, eating more fiber by prioritizing vegetables and whole grains, eating less sugar, swapping out saturated fats for mono- and polyunsaturated fats, consuming adequate protein and self-monitoring your progress.

How many carbs are right for you?

To determine the right amount of carb grams to aim for in your eating plan, choose one of the categories below that best matches your stature, weight status, weight goals and activity level.

Consider the targets a starting point. Get a referral from your primary care provider or endocrinologist to meet with a dietitian and diabetes educator, and/or to attend a diabetes self-management education and support (DSMES) program to determine the best goals for your health.

Category 1: A Woman of Small Stature Who Wants to Lose Weight

You're a woman who wants to lose weight, is small in stature and/or gets limited exercise. Consider the following:

Height: 4'10" to 5'2"

Daily calorie range: 1,200–1,400

Carb grams/day range*: 135–228 grams

Carb grams/meal range (3 meals per day): 45–76 grams

*Based on 45–65% of calories from carbohydrate

Category 2: A 65-Year-Old Woman Who Wants to Lose Weight

You're a woman who is 65 years of age or older, wants to lose weight, has an average to large stature and/or gets limited exercise. Here are some basic calorie and carb recommendations:

Height: 5'3" to 5'8"

Daily calorie range: 1,400–1,600

Carb grams/day range*: 158–260 grams

Carb grams/meal range (3 meals per day): 53–87 grams

*Based on 45–65% of calories from carbohydrate

Category 3: A Woman Who Wants to Maintain Weight

You're a woman who is under 65 years of age, is of moderate to large stature and is at a healthy weight. Consider the following:

Height: 5'8" to 6'

Daily calorie range: 1,600–1,900

Carb grams/day range*: 180–308 grams

Carb grams/meal range (3 meals per day): 60–103 grams

*Based on 45–65% of calories from carbohydrate.

Note: Women who are under 65 years of age, moderate to large in stature, at a healthy weight and get a lot of exercise may need more calories and grams of carbohydrate.

Category 4: A Man of Small Stature Who Wants to Lose Weight

You are a man who is 65 years of age or older, are smaller in stature, want to lose weight, and/or get limited exercise. Here are your recommendations:

Height: 5'4" to 5'8"

Daily calorie range: 1,600–1,900

Carb grams/day range*: 180–308 grams

Carb grams/meal range (3 meals per day): 60–103 grams

*Based on 45–­65% of calories from carbohydrate.

Note: These recommendations are the same for a woman of small stature who wants to maintain weight.

Category 5: A Man Who Wants to Maintain Weight

You're a man who is 65 years of age or younger, is moderate to large in stature, at a healthy weight and gets limited exercise. Here are some basic calorie and carb recommendations:

Height: 5'8" or taller

Daily calorie range: 2,300–2,800

Carb grams/day range*: 259–455 grams

Carb grams/meal range (3 meals per day): 86–151 grams

*Based on 45–65% of calories from carbohydrate.

Note: Men who are under 65 years of age, moderate to large in stature, at a healthy weight and get a lot of exercise may need more calories and grams of carbohydrate.

What if you're making healthy choices and still have high blood sugar?

According to American Diabetes Association guidelines, most people with type 2 diabetes should start taking a blood glucose-lowering medication, typically metformin (a generic medication that helps the body better use the insulin you still make), as soon as they are diagnosed.

Most people diagnosed with type 2 diabetes have had blood sugar levels in the diabetes range for months if not years before diagnosis. Don't think of taking blood glucose-lowering medication as failing. Type 2 diabetes, with prediabetes as its starting point, is a progressive disease during which people slowly lose their insulin-making capabilities over time. It's of no health value to severely restrict the amount of carbs you eat to manage your blood sugar levels and/or to delay medication. The recommended course of action to stay healthy with type 2 diabetes is to get blood glucose, cholesterol and blood pressure numbers under control soon after the time of diagnosis-and maintain target goals-adjusting diet and medication as needed.

The bottom line

The amount of carbs you should eat per day depends on a variety of factors, such as your gender, weight and height. But, getting closer to 40-45 percent (or less) of your calories from carbohydrates may better improve blood sugar control and aid weight loss. It's most important to choose quality carbs-that is, carbs that are high in fiber and low in sugar-and limit refined sugars. Space carbs evenly throughout the day, and stick to a low-to-moderate carb count that you can keep up with long-term. Losing weight will improve diabetes control, but more research is needed to determine if a low-carb or low-fat diet is most effective long-term. There is no "one-size-fits-all" recommendation. Talk to your physician, dietitian and/or diabetes educator to learn more about what works best for you in order to create your individual care plan.

Related:

Some original reporting by Hope Warshaw, RD, CDE

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