Short-term low carbohydrate diet may target type 2 diabetes, study finds

Patients with type 2 diabetes who follow a strict low carbohydrate diet for six months may experience greater rates of remission compared with other recommended diets without adverse effects, according to a new study published by The BMJ.

Type 2 diabetes is the most common form of diabetes worldwide, and diet is recognized as an essential part of treatment. However, uncertainty remains about which diet to choose, and previous studies have reported mixed results, the researchers said.

For the study, researchers set out to assess the effectiveness and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes, compared with (mostly low fat) control diets. Their findings are based on analysis of published and unpublished data from 23 randomized trials involving 1,357 participants.

LCDs were defined as less than 26% daily calories from carbohydrates and VLCDs were defined as less than 10% daily calories from carbohydrates for at least 12 weeks in adults (average age 47 to 67 years) with type 2 diabetes.

Outcomes were reported at six and 12 months and included remission of diabetes or reduced blood sugar levels with or without the use of diabetes medication, weight loss, adverse events, and health-related quality of life.

Although the trials were designed differently, and were of varying quality, the researchers said they were able to allow for this in their analysis. Based on low to moderate certainty evidence, the researchers found that patients on LCDs achieved higher diabetes remission rates at six months compared with patients on control diets, without adverse events.

For example, based on moderate certainty evidence from eight trials with 264 participants, those following an LCD experienced, on average, a 32 percent absolute risk reduction, 28 fewer cases per 100 followed, in diabetes remission at six months. LCDs also increased weight loss, reduced medication use, and improved body fat and triglyceride concentrations at six months.

The researchers acknowledge that most benefits diminished at 12 months, but said providers might consider short-term strict low carbohydrate diets for managing type 2 diabetes, while actively monitoring and adjusting diabetes medication as needed.

"Future long term, well-designed, calorie-controlled randomized trials are needed to determine the effects of LCD on sustained weight loss and remission of diabetes,” they said in a statement, “as well as cardiovascular mortality and major morbidity.”