Daily Dose: Low-carb Diet May Help Improve Untreated HbA1c

Patient Care brings primary care clinicians a lot of medical news every day—it’s easy to miss an important study. The Daily Dose provides a concise summary of one of the website's leading stories you may not have seen.

On October 26, 2022, we reviewed a study published in JAMA Network Open that analyzed the effect of a behavioral intervention promoting a low-carbohydrate diet compared with usual diet on 6-month changes in HbA1c among persons with elevated untreated HbA1c.

The study

Adults aged 40-70 years with untreated HbA_1c of 6.0% to 6.9% were randomized to a low-carbohydrate diet intervention (target <40 net grams of carbohydrates during the first 3 months; <60 net grams for months 3 to 6) or usual diet. The low-carbohydrate diet group received dietary counseling.

Researchers identified 2722 participants for potential study inclusion of which 962 were screened and a total of 150 were randomized equally to the low-carbohydrate dietary intervention or to the usual diet intervention.

The results

Adherence to the low-carbohydrate dietary intervention was associated with significantly greater reductions at 6 months in HbA1c (net difference, –0.23% [95% CI, –0.32% to –0.14%]; P<.001), fasting plasma glucose (–10.3 mg/dL [95% CI, –15.6 to –4.9 mg/dL]; P<.001), and body weight (–5.9 kg [95% CI, –7.4 to –4.4 kg]; P<.001) compared to adherence to usual diet.

Author's Conclusion

“In this 6-month randomized clinical trial, a low-carbohydrate diet intervention led to larger reductions in HbA1c than usual diet among adults with elevated untreated HbA1c (6.0–6.9%), though we were unable to assess its effects independently of weight loss. This dietary approach may be an option for people with or at high risk of T2D to improve glycemic and other markers and should be studied further and over longer time periods in other populations and settings."

Click here for the full study review.