For the literature review and meta-analysis, the researchers looked at 23 studies that included 1,357 participants. The subjects were primarily overweight and obese and had a diagnosis of type 2 diabetes. The researchers evaluated the effect of different carbohydrate intakes on the subjects’ health, specifically as it related to diabetes.
The study featured two types of low-carb diets: A low-carbohydrate diet and a very low-carbohydrate diet. A low-carbohydrate diet was defined as less than 26% carbohydrate intake of a 2,000 calorie diet, and a very low-carbohydrate diet was defined as carbohydrate intake making up more than 10% of a 2,000 calorie diet.
After six months, the people on low-carbohydrate diets achieved higher rates of diabetes remission (defined as a Hemoglobin A1C of less than 6.5% or a fasting glucose level of less than 7 mmol/L) compared to people on (mostly) low-fat control diets.
Additionally, the subjects saw improvements in weight loss, triglyceride levels, and insulin sensitivity at six months. However, those effects diminished at 12 months, specifically among the group following the low-carbohydrate diet.
Following very low-carbohydrate diets did not result in as much weight loss at six months. The authors noted that this might be because a very low-carbohydrate diet can be difficult to adhere to.
Should Everyone With Diabetes Limit Carbs?
There is not a one-size-fits-all amount of carbohydrates that people with diabetes should eat. However, the American Diabetes Association suggests that people with the condition aim to get about half of their daily calories from carbs.
The Benefits
Low-carbohydrate diets (typically defined as more than 20% carbohydrates) are increasingly being used to help people with obesity and type 2 diabetes better manage their health.
Studies have shown that low carbohydrate diets are safe and can help people achieve weight loss, lower medication doses, and even diabetes remission.
The Risks
Hailey Crean, MS, RD, CDE, CSOWM, registered dietitian and certified diabetes educator at Hailey Crean Nutrition, LLC, tells Verywell about a concern they have about the current study’s findings: the health effects of a low-carb diet that were not necessarily related to diabetes.
Even though the subjects who followed a low carbohydrate diet did exhibit positive outcomes, the researchers also “found what they define as ‘clinically important, but not statistically significant, worsening of quality of life and low-density lipoprotein (LDL) cholesterol at 12 months.’"
“With the increased cardiovascular disease risk and dyslipidemia (abnormalities on a lipid panel test) that can occur in type 2 diabetes, LDL increases would be important to monitor for individuals wanting to follow a low carb diet,” Crean says.
Carbs: Quantity vs. Quality
While researchers assessed the carbohydrate quantity of the subjects’ diets, the quality of the food was not taken into account. Crean says that consuming carbohydrates from highly processed sources as opposed to whole grain and vegetable sources is a key factor for a healthy diet.
A meta-analysis published in The Lancet in 2018 found that low carbohydrate diets were associated with increased mortality, with minimal risk observed at 50% to 55% carbohydrate intake. Low-carbohydrate diets that were rich in animal protein and fat were associated with higher mortality.
However, the diets that focused on plant-based proteins and fat were associated with lower mortality. The findings highlighted that the quality of the food, and not just the carbohydrate content, should be considered when focusing on mortality risk.
How To Choose Carbohydrates to Manage Diabetes
Regardless of whether you are eating a very low carb diet, a moderate carb diet, or something in between, the type of carbohydrates that you eat matters.
Brittany Scanniello, RD, a Colorado-based registered dietitian, suggests that when considering carbohydrate options, people with diabetes choose foods like:
Whole grains like brown rice and oatmeal Fruits like pears and blueberriesStarchy vegetables like sweet potatoes and peasPulses like lentils and chickpeas
At the same time, people with diabetes can benefit from limiting their intake of refined carbohydrates, such as:
White breadSugar and concentrated sweetsSodaCookiesRefined snacks like pretzels made with white flour
Choosing nutrient-dense foods fuels your body with key vitamins and minerals, as well as fiber. Research has shown that consuming dietary fiber can reduce fasting blood glucose levels and lower hemoglobin A1C values.
