Pair-Feeding Study Designs Can Create Biases and Inflate Type I Error Rates: A Simulation Study

Authors

• Wasiuddin Najam
• Daniel E Kpormegbey
• Deependra K Thapa
• Bret Rust
• Lilian Golzarri-Arroyo
• Lance H Baumgard
• Louis Wai-Tong Fan
• Joseph G Ibrahim
• Edith J Mayorga
• David B Allison

Language

English

Publication Date

2-1-2026

Journal

Obesity

DOI

10.1002/oby.70079

PMID

41286579

PMCID

PMC12850568

PubMedCentral® Posted Date

11-24-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Objective: Pair-feeding is a study design element where one group's food intake is provided to another group to assess whether a treatment effect is independent of food intake. Investigators often assume equivalent food intake across experimental conditions and exclude it from the statistical analysis. However, the impact of this practice on type I error (T1Er) rates has not been quantified.

Methods: We conducted a Monte Carlo simulation in which animals were assigned baseline weights and food intakes, then randomized to non-pair-fed or pair-fed groups. Daily food intake for both groups was initially drawn from the baseline food intake distribution. For pair-fed animals, food intake was truncated if it exceeded the previous day's intake of the matched non-pair-fed animal (individual pair-feeding) or the group's average (group pair-feeding). Weight changes were calculated as a function of food intake, and final weight change was analyzed with and without adjusting for mean food intake.

Results: Both individual and group pair-feeding inflated T1Er rates ranging from 0.12 to 0.71 in unadjusted models. However, adjustment for food intake reduced error rates to around 0.05.

Conclusions: Under some circumstances, pair-feeding designs can inflate T1Er rates. Investigators can mitigate this inflation by adjusting the analyses for food intake.

Keywords

Animals, Monte Carlo Method, Eating, Bias, Research Design, Computer Simulation, Body Weight, Feeding Behavior, bias, data analysis, pair‐feeding, rigor, statistical science, study design, type one error

Published Open-Access

yes

Recommended Citation

Najam, Wasiuddin; Kpormegbey, Daniel E; Thapa, Deependra K; et al., "Pair-Feeding Study Designs Can Create Biases and Inflate Type I Error Rates: A Simulation Study" (2026). Children’s Nutrition Research Center Staff Publications. 328.
https://digitalcommons.library.tmc.edu/staff_pub/328