This study evaluated the effects of time-restricted eating (TRE) on CGM-measured glycaemic control in people with type 2 diabetes. Participants wore blinded intermittently scanned CGM devices and filled in paper- or app-based dietary logs throughout, and had a 2-week period of normal habitual eating followed by 4 weeks of TRE, in which eating was restricted to the hours of 10 am to 7 pm for at least 5 out of 7 days per week.
Nineteen adults with type 2 diabetes (mean HbA1c 60 mmol/mol) completed the study and had sufficient data for analysis. The mean eating window was 2.5 hours shorter in the TRE study arm; however, daily dietary intake, physical activity and sleep duration did not differ between the arms.
Compared with the normal eating period, mean 24-hour glucose concentration fell by 0.7 mmol/L (P=0.02) during the TRE period, and the 24-hour glucose area under the curve fell by 0.9 mmol/L/hour (P=0.01). Time in range also increased by 10% (to 73%) and time below range fell by 10% (to 26%).
The authors conclude that following a 9-hour window of TRE for at least 5 days a week improves daily measures of glycaemic control, despite calorie intake remaining the same, in people with type 2 diabetes. The main study limitations were the pre–post design and lack of a control group, and the short follow-up.