Hypocaloric start (≤ 70% of expenditure) in the first days, advance to 80-100% after day 3, protein about 1.3 g/kg/day, adjust for obesity and count non-nutritional calories.
At the bedside
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Weight
Use actual weight if BMI < 30; for obesity use adjusted or ideal body weight (see table).
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Early phase (days 1-3)
Day 1-3Hypocaloric: ≤ 70% of energy expenditure; avoid overfeeding.
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Later phase
Day 3-7After day 3 advance to 80-100% of measured or estimated energy expenditure.
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Protein
Target ~1.3 g/kg/day progressively; very high protein (≥ 2.2 g/kg) early did not improve outcomes and may harm patients with AKI or high organ failure scores (EFFORT Protein).
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Shock
In ventilated patients with shock, lower energy/protein in the first week (NUTRIREA-3) was associated with faster recovery and fewer complications.
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Count non-nutritional calories
Propofol 1.1 kcal/mL, dextrose 5% (~170 kcal/L), citrate in CRRT; reduce feed if large.
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Micronutrients and glucose
Provide micronutrients with feeding; insulin if glucose > 180 mg/dL (target about 140-180 mg/dL).
Practical targets
| Group | Energy | Protein |
|---|---|---|
| BMI < 30, early phase | ≤ 70% of EE (~15-20 kcal/kg) | Start low, advance |
| BMI < 30, after day 3 | 20-25 → 25-30 kcal/kg | ~1.3 g/kg (ESPEN); 1.2-2.0 (ASPEN) |
| BMI 30-50 (ASPEN) | 11-14 kcal/kg actual weight | 2.0 g/kg IBW (BMI 30-40); 2.5 g/kg IBW (BMI ≥ 40) |
| BMI > 50 (ASPEN) | 22-25 kcal/kg IBW | 2.5 g/kg IBW |
| CRRT | As above | Add ~0.2 g/kg/day for losses (up to 1.5-1.7 g/kg) |
Calculators for this topic
Predicted (ideal) body weight
ARDSNet predicted body weight from height and sex. Use for tidal volume, not for most drug doses.
Adjusted body weight
IBW + 0.4 × (actual − IBW). Used for some drug doses (e.g. aminoglycosides) and nutrition in obesity.
Body mass index
Weight ÷ height². Asian cut-offs differ (overweight ≥ 23, obese ≥ 25 in Indian guidance).
References
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Pathophysiology
In the acute phase, endogenous glucose production (up to 50-75% of needs) cannot be suppressed by feeding, so full exogenous calories cause overfeeding; autophagy may be beneficial early. Anabolic potential increases in recovery.
Evidence
- ESPEN 2019/2023: hypocaloric early, 1.3 g/kg protein progressively [Singer 2019; 2023].
- EFFORT Protein (1,329 patients): higher protein did not improve time to discharge alive; possible harm in AKI and high SOFA [Heyland 2023].
- NUTRIREA-3: low vs standard calories/protein in shock - similar mortality, faster readiness for discharge [Reignier 2023].
- TARGET: energy-dense EN (1.5 kcal/mL) did not improve survival [TARGET 2018].
Controversies
- Optimal protein dose and timing; indirect calorimetry for all.
🇮🇳 India notes
- Indian patients may have lower muscle mass ('thin-fat' phenotype) - assess muscle by ultrasound or clinical judgement; use IBW-based estimates for obesity.
- Vegetarian diets are common; commercial high-protein formulas or whey/soy protein supplements are used to meet targets.
References
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