What is a low carb diet?
Carbohydrates (also called “carbs”) are found in both healthy and unhealthy foods. Carbs include bread, beans, milk, potatoes, cookies, pasta, soda, and corn. For a person with diabetes, lowering the amount of carbs can help improve blood sugar control.
However, there are different definitions of a “low carb diet.” For example, a low carb diet can range from less than 10% to less than 26% of daily calorie intake coming from carbs. Some research suggests that diets are low carb if they are made up of 37% or less carbohydrates, compared to 50% for higher carbohydrate diets. Diets with even lower carb intake levels (less than 10% of daily calories) cause ketones to appear in the blood; this is known as a ketogenic (or keto) diet.
Very low carbohydrate diets, especially those that cause ketones, are controversial. For example, there are concerns about diets high in saturated fat, which often occurs when eating a very low carb diet. So far, there is limited research on low carb diets for people with diabetes; most studies lasted less than a year. In addition, supporters of plant-based diets have environmental concerns about low carb diets. This is because low carb diets are usually high in animal products, such as meat. You can lower carbs when following a vegetarian or vegan diet. However, vegan ketogenic diets are more difficult to follow.
What do we know?
A new report from the U.K. suggests that a diet lower in carbs can be helpful for up to 6 months for adults with type 2 diabetes who are overweight or obese. For some people with type 2 diabetes, a low carb diet might even move their HbA1c levels into a healthy (non-diabetic) range. It can also reduce the need for medicines for diabetes.
Another benefit is that people on these types of diets lose more weight compared to people on higher carb diets over 3 months. After 3 months, the research is unclear. We also do not know whether it would work for all adults with type 2 diabetes, rather than just for those with overweight or obesity. Adults with type 2 diabetes eating a lower carb diet should include whole grain or higher fiber foods and a variety of fruits and vegetables, but limit saturated fats.