ABSTRACT
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.
Abbreviations
EF: | = | eating frequency |
LDL: | = | low-density lipoprotein |
HDL: | = | high-density lipoprotein |
IGF-1: | = | insulin-like growth factor-1 |
GH: | = | growth hormone |
mRNA: | = | messenger RNA (ribonucleic acid) |
FHCRC: | = | Fred Hutchinson Cancer Research Center |
BMI: | = | Body Mass Index; measured in kg/m2 |
NSAIDS: | = | nonsteroidal anti-inflammatory drugs |
DEXA: | = | dual-energy X-ray absorptiometry |
ELISA: | = | enzyme-linked immunosorbent assay |
GEE: | = | generalized estimating equation |
NCI: | = | National Cancer Institute |
SD: | = | Standard deviation |
Acknowledgments
We thank the Meals and Grazing Study subjects and the FHCRC Prevention Center staff for their help completing this project. We also thank Pamela Yang for providing technical assistance on laboratory assays. This work was supported by the FHCRC and grant R25CA094880 from the National Cancer Institute.
Disclosure Statement
The authors declare that they have no conflicts of interest.
Authors' Contributions
M. L. N. and M. P. conceived of the study, carried out study design and coordination, and drafted the manuscript. A. D. and M. K. provided guidance for study design and manuscript preparation. C. W. provided oversight for data analysis. X. S. carried out sample analysis. M. L. N. oversaw all aspects of study design, coordination, and data analysis; drafted the manuscript; and secured study funding. All authors read and approved the final manuscript.