Time‐restricted eating did not alter insulin sensitivity or β‐cell function in adults with obesity: A randomized pilot study

OBJECTIVE: Decreased insulin sensitivity and impairment of β‐cell function predate and predict development of type 2 diabetes mellitus. Time‐restricted eating (TRE) might have a benefit for these parameters. The objective of this pilot study was to investigate this possibility. METHODS: Secondary analysis of a randomized controlled trial comparing 12 weeks of TRE (8‐hour eating window) to unrestricted eating (non‐TRE) was performed. Participants were adults with overweight or obesity and without diabetes. Two‐hour oral glucose tolerance testing was performed at baseline and end‐intervention. Glucose tolerance test‐derived measures of insulin sensitivity, insulin secretion, and β‐cell function were compared between groups. RESULTS: Participants (17 women/3 men with mean [SD] age 45.5 [12.1] years and BMI 34.1 [7.5] kg/m(2)) with a prolonged eating window (15.4 [0.9] hours) were randomized to TRE (n = 11) or non‐TRE (n = 9). The quantitative insulin sensitivity check index (QUICKI), Stumvoll index, Avignon index, insulinogenic index, insulin area under the curve/glucose area under the curve, and oral disposition index did not differ between the TRE and non‐TRE groups at end‐intervention. CONCLUSIONS: In adults with overweight or obesity and without diabetes, TRE did not significantly alter insulin sensitivity, insulin secretion, or β‐cell function over a 12‐week intervention. Whether TRE is beneficial in adults with prediabetes or type 2 diabetes mellitus warrants further investigation.