Research

Energy balance

Post-hoc exclusion of participants based on 'Unaccounted Energy' (a post-randomization variable) in feeding studies introduces severe confounding bias, artificially attenuating the observed increase in Total Energy Expenditure (TEE) associated with low-carbohydrate diets.

When evaluating low-carb diet studies, be skeptical of analyses that exclude participants who didn't 'adhere' perfectly. These exclusions often rely on flawed metrics (like Unaccounted Energy) that introduce bias. The original findings of increased energy expenditure on low-carb diets remain robust even when accounting for these methodological errors.

StrongRefutesHIGH confidence
Here, we show why that analysis, based on a post-randomization variable linked to the outcome, introduced severe confounding bias. With control for confounding, the diet effect on TEE remained strong in a reanalysis.
David S. Ludwig et al. · European Journal of Clinical Nutrition · 2020

Why this rating

Based on a rigorous reanalysis of a randomized controlled trial (RCT) data with covariate adjustment.

Source

Testing the carbohydrate-insulin model of obesity in a 5-month feeding study: the perils of post-hoc participant exclusions

David S. Ludwig et al. · European Journal of Clinical Nutrition · 2020

DOI 10.1038/s41430-020-0658-8

rct · n=145Cited 10×
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DOI resolved against Crossref · corpus check 2026-06-10

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