Whole-body energy expenditure is the summed metabolic activities of tissues and, to remove the influence of body size, ratios of energy expenditure to body mass are often applied but can generate spurious differences. In 2011, a group of experts proposed adoption of ANCOVA for the analysis of metabolic rate but, seven years later, analyses based on ratios remain the most frequent. We discuss some of the barriers to adopting better analytical procedures.
Fernández-Verdejo, R., Ravussin, E., Speakman, J. R., & Galgani, J. E. (2019). Progress and challenges in analyzing rodent energy expenditure. Nature methods, 16, 797-799. https://doi.org/10.1038/s41592-019-0513-9