Randomized Trial Testing the Effects of Eating Frequency on Two Hormonal Biomarkers of Metabolism and Energy Balance.

BACKGROUND Eating frequency (EF) may influence obesity-related disease risk by attenuating postprandial fluctuations in hormones involved in metabolism, appetite regulation, and inflammation. MATERIALS/METHODS This randomized crossover intervention trial tested the effects of EF on fasting plasma insulin-like growth factor-I (IGF-1) and leptin. Fifteen subjects (4 males, 11 females) completed two eucaloric intervention phases lasting 21 days each: low EF ("low-EF"; 3 eating occasions/day) and high EF ("high-EF"; 8 eating occasions/day). Subjects were free-living and consumed their own meals using individualized structured meal plans with instruction from study staff. Subjects completed fasting blood draws and anthropometry on the first and last day of each study phase. The generalized estimated equations modification of linear regression tested the intervention effect on fasting serum IGF-1 and leptin. RESULTS Mean (± SD) age was 28.5 ± 8.70 years, and mean (± SD) Body Mass Index was 23.3 (3.4) kg/m2. We found lower mean serum IGF-1 following the high-EF condition compared to the low-EF condition (P < 0.001). There was no association between EF and plasma leptin (P = 0.83). CONCLUSION These results suggest that increased EF may lower serum IGF-1, which is a hormonal biomarker linked to increased risk of breast, prostate, and colorectal cancer.