Sticking to a low-carbohydrate diet helped people with prediabetes bring down their HbA1c in just a few months, a randomized clinical trial found.
Compared with those eating their typical diet, people with an untreated, elevated HbA1c who ate a low-carb diet saw a significantly greater improvement in fasting plasma glucose (-10.3 mg/dL, 95% CI -15.6 to -4.9) at month 6, reported Kirsten S. Dorans, ScD, of Tulane University School of Public Health and Tropical Medicine in New Orleans, and colleagues.
Those on the low-carb diet, which also included dietary counseling, also saw a 0.23% greater drop in HbA1c at this time (95% CI -0.32 to -0.14), they wrote in JAMA Network Open.
Although the researchers acknowledged this HbA1c reduction was “modest,” they explained it was still a little greater than the 0.17% reduction seen in the lifestyle intervention arm of the DPP trial, which subsequently led to a 58% reduced risk for type 2 diabetes progression over 2.8 years.
Participants on the low-carb diet also spent longer in target glucose range (70-120 mg/dL) according to readings from their continuous glucose monitors. In addition, they had significantly lower average 24-hour glucose levels than those eating their usual diets.
And low-carb-dieters also saw a 5.9 kg (95% CI -7.4 to -4.4) greater reduction in body weight (about 13 lb) after being on the diet for half the year. This was likely due to the significant decrease in caloric intake seen among those on the low-carb diet.
“Few participants had detectable urinary ketones, suggesting ketosis was unlikely to account for the findings,” the authors noted.
The authors cautioned that “the study was unable to evaluate its [low-carb diet] effects independently of weight loss.”
Still, Dorans said in a statement that “The key message is that a low-carbohydrate diet, if maintained, might be a useful approach for preventing and treating type 2 diabetes, though more research is needed.”
Her group noted that study limitations included self-report of dietary intake, which is subject to potential recall bias. Also, “participants…