Do People With Diabetes Have to Follow a Low-Carb Diet?

How a very low carb diet may affect your blood sugars

Complex carbohydrates are okay for a person with diabetes.
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If you're living with type 2 diabetes, you may be wondering if you should follow a low-carb diet. In fact, some recent studies suggest that an ultra-low carbohydrate may be able to reverse diabetes. Let's take a look at the role of carbohydrates in a healthy diet for people with diabetes, and what studies to date have been telling us about the impact of low-carb or very low-carb diets on blood sugar.

The Role of Carbohydrates in Our Diet

Carbohydrates include sugars and starches and together they make up one group of macronutrients; the other two are protein and fat. When you consume carbohydrates, your digestive system breaks carbohydrates down into individual sugar units that are absorbed into your blood. This triggers the release of insulin, a protein that helps move glucose out of your blood and into your body's cells so it can be used for energy. Sugars that aren't immediately used for energy are either stored for a while or converted to fat (when you eat more food than your body needs).

You need to consume carbohydrates every day because they are your body's primary energy source. The Academy of Nutrition and Dietetics and the Dietary Guidelines for Americans, 2015-2020 recommends you get about half of your daily calories from carbohydrate sources; this includes people with diabetes. This translates to roughly 250 to 300 grams of carbohydrates every day, but it depends on your size, sex, and how active you are.

History of Carbohydrates in a Diabetic Diet

The amount of carbohydrates recommended in a diabetic diet has had a roller-coaster history, and at the current time remains an area of some controversy.

Before insulin or diabetes medications were available, eating a low-carb diet was the only treatment available. That changed with both the discovery of insulin and medications and when we began to learn about the role of fat in heart disease. Since fat was considered a major culprit in heart disease, and since heart disease is common in people with diabetes, the recommended intake of carbohydrates actually increased. Since a low-carb diet means more fat, it was not recommended. Now we are learning that the amount of fat in our diet is much less important than we once thought. In addition, eating a low-carb diet became the new way to achieve weight loss, also important with diabetes.

What are the current arguments both for and against a low-carb diet for people with diabetes?

Argument Against a Low-Carb Diet for Diabetes

According to the Academy of Nutrition and Dietetics, diabetic research hasn't supported any combination of carbs, fat, and protein to be any better than what's recommended for a regular healthy diet. What's thought to be more important is choosing healthful sources of complex carbohydrates, keeping your daily carbohydrate intake consistent, and losing weight if you're overweight or obese.

Argument for Low-Carb Diet for Diabetes

In talking about a low-carb diet and its effect on diabetes, it's important to define what this means. A low carb diet is defined as one in which carbohydrates make up 26 percent or less of calories. In contrast, a "very low-carb diet" or "ultra low-carb" diet has been looked at more extensively. A very low-carb diet is much more restrictive, with carbohydrates limited to only 10 percent of calories or less.

A 2015 review looked at almost 100 studies to see if there were any advantages to eating a very low-carb diet. The authors drew several conclusions, some of which included:

  • A low-carb (very low carb) diet resulted in lower blood sugars.
  • A reduction in blood sugars on a low carb diet didn't require weight loss, though weight loss was often a "side effect" of a low carb diet. (Learn more about weight loss on a low carb diet).
  • People with type 2 diabetes were sometimes able to reduce the dose of their diabetic medications or eliminate them completely.
  • Changing to a low carb diet was fairly easy.
  • There were no side effects on the low carb diet.

Overall, they concluded that a low-carb diet should be the first step in treating type 2 diabetes.

There are arguments both for and against their claims, but for those who find this information compelling, it's not just diabetes and lipids that might improve. There are several health benefits of a low-carb diet that have been found in medical studies ranging from improvements in conditions ranging from irritable bowel syndrome to acne.

If You Choose to Adopt a Low-Carb Diet

If you're interested in following a low-carb diet it's important to talk to your health care provider, diabetes educator, or a dietician or nutritionist who specializes in medical nutrition therapy for diabetes prior making any dietary changes. Since your blood sugars may very well decrease, talk with your doctor about medications and low carb diets. In addition to affecting your diabetes medications, changing to a low-carb diet may affect your high blood pressure medications as well.

Since the major "side effects" of a low-carb diet are weight loss and low blood sugar, it's important to monitor your blood glucose very closely and keep a journal of dietary intake alongside your readings at first. The the first week on a low carb diet can be challenging, with people complaining of both carb withdrawal in the first few days followed by a "carb crash" occurring roughly 3 to 5 days after your switch.

Take a moment to learn the basics of a low-carb diet as well as common mistakes people make when starting a low-carb diet.

After you talk with your doctor and learn about low-carb diets, here are some low-carb dinner recipes to get you started.

Bottom Line on a Low-Carb Diet for Diabetes

In general, it's been thought that a low-carb is unnecessary for people with diabetes, though some studies suggest that a very low-carb diet may sometimes even reverse the disease. Before making any changes, it's important to talk with your doctor. In general, going on a low-carb diet has few side effects with the exception of weight loss, but doing so may result in changes in your blood sugars which could affect the medications you are taking. This is currently an area of active research, and it's likely we will be learning more about the "ideal" intake of carbohydrates in a diabetic diet in the near future.

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