In Reply Dr Brand-Miller and colleagues suggest that the duration of the OmniCarb study was too short, citing a systematic review and meta-analysis.1 However, that review only concerned glycemic control in patients with diabetes, a topic that does not pertain to the OmniCarb study. A more relevant meta-analysis2 of 14 trials with durations of at least 6 months found no effect of lowering glycemic index on lipid levels or fasting glucose, although fasting insulin was reduced. In addition, the trials cited in our article of at least 6 months’ duration found lowering glycemic index did not affect insulin sensitivity or blood pressure.
Sacks FM, Appel LJ, Carey VJ. Low vs High Glycemic Index Diet—Reply. JAMA. 2015;313(13):1372-1373. doi:10.1001/jama.2015.2081