Practical implications of "personalized nutrition therapy"

When considering "personalized nutrition therapy," particularly in the intensive care unit (ICU), the default response is indirect calorimetry (IC). However, predictive equations (PEs) remain more commonly used due to cost and logistical constraints. A recent paradigm shift in how nutrition support is viewed during the early phases of critical illness has also called into question if exact energy targets are what constitutes "personalized nutrition therapy." This review examines recent evidence comparing IC and PE based nutrition support in the ICU, highlighting practical issues around timing, patient selection, and nutrition adequacy and aims to redefine the focus of personalized nutrition therapy moving forward.

Systematic reviews and meta-analyses from 2020 to 2025 yield mixed results. Some suggest that IC-guided nutrition may reduce short-term mortality; others report higher mechanical ventilation days. Studies also show IC-based protocols typically deliver more calories than PE-based methods, potentially risking overfeeding if not carefully managed. Special populations - large burn cases, patients with obesity, and older adults - can show wide discrepancies between measured vs. predicted energy expenditures.

While IC can capture individual metabolic demands more accurately than PEs, especially in complex patients, logistical barriers and uncertainty about the ideal calorie target complicate its adoption. Evidence to support early use of IC in the ICU remains inconclusive. Further research into emerging patient identifiers based on phenotypic, metabolomic, or mechanistic profiles may redefine personalized critical care nutrition.