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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.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.Participants (17 women/3 men with mean [SD] age 45.5 [12.1] years and BMI 34.1 [7.5] kg/mIn 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.

Obesity is a well-established risk factor for insulin resistance and type 2 diabetes mellitus, and body fat distribution has important implications for this metabolic risk. In this cross-sectional study, we used dual X-ray absorptiometry body composition data from 123 young adult participants with overweight or obesity, and correlated with 2 indices of insulin resistance calculated from oral glucose tolerance tests. Participants were 70% women, with mean (standard error) age 30.1 (0.6) yr, body mass index (BMI) 34.0 (0.6) kg/m(2), homeostatic model assessment of insulin resistance (HOMA-IR) of 2.1 (0.2), and Matsuda insulin sensitivity index (Matsuda ISI) of 5.8 (0.4). In women, the strongest correlations were observed with the android-to-gynoid ratio (r = 0.52, p < 0.001 for HOMA-IR; r = 0.46, p < 0.001 for Matsuda ISI), and these correlations remained significant after adjustment for BMI. For men, the strongest correlations were with android fat mass (r = 0.40, p = 0.01 for HOMA-IR; r = 0.37, p = 0.02 for Matsuda ISI). Visceral adipose tissue was correlated with HOMA-IR and Matsuda ISI in women, and only with Matsuda ISI in men. BMI correlated with HOMA- IR and with Matsuda ISI in both women and men. Regional adiposity determined by dual X-ray absorptiometry correlates with indices of insulin resistance in sedentary young adults with overweight and obesity.

Background: Despite the benefits of aerobic exercise on body composition, runners with high body mass index (BMI) remain understudied. We examined body composition differences between sedentary insulin-resistant [obese insulin-resistant sedentary (OS-IR)], sedentary insulin-sensitive [obese insulin-sensitive sedentary (OS-IS)], and trained [obese trained (OT)] individuals with high BMI (≥25 kg/m(2)). We hypothesized that after matching for high BMI, OT individuals would have less fat mass (absolute and relative) and greater lean mass than OS-IR or OS-IS individuals. Methods: This is a retrospective analysis of OS-IR, OS-IS, and OT participants selected for similar age, sex, and BMI. Activity was self-reported. OT participants exercised at least 30 min/day (predominantly running) for 3–5 days/week. OS-IS and OS-IR participants actively exercised