Fig. 1

Examples of experimental variables for systems nutrition research. Reductionistic approaches typically focus on measures of physiology (human on the right) and one or a few environmental variables (left). Some variables may represent both input and output of the human system, and some output variables may affect other input variables (e.g., stress effect on diet). The input of systems nutrition research would capture and conceptually organize those environmental variables that alter physiological variables, as well as comprehensive analyses of physiological processes. Some environmental variables may be challenging to quantify (e.g., the built environment) but may be recorded as metadata associated with the experimental results and important for interpretation of the data. This figure describes primarily the data that may be captured for analyses, and a separate process captures the analysis pipeline