Calculating Basal Energy Expenditure for Underweight Patients with Severe Stress

Estimating Basal Energy Expenditure

The European Society for Clinical Nutrition and Metabolism (ESPEN) recommends estimating basal energy expenditure using the Harris-Benedict equation for men (BEE = 66.4730 + 13.7516 × weight + 5.0033 × height - 6.7550 × age), then multiplying by a stress factor of 1.5-2.0 for severe stress to determine total energy requirements 1, 2
For older adults (≥65 years), ESPEN suggests a simplified weight-based approach: REE ≈ 18-20 kcal/kg/day 5
The Harris-Benedict equation shows reduced accuracy in patients with low BMI, with prediction accuracy dropping to around 45% in severely malnourished patients 7

Energy requirements increase during severe stress due to inflammation, fever, and metabolic demands, with a commonly used severe stress factor of 1.5-2.0 5
Total Energy Expenditure (TEE) can be calculated as BEE × stress factor, with an example calculation for an underweight patient: TEE = 1,470 kcal × 1.5-2.0 = 2,205-2,940 kcal/day 5, 4

Severely underweight patients are at high risk for refeeding syndrome, and the target caloric intake should be achieved cautiously and slowly, starting with lower caloric intake and gradually increasing over 7-10 days 9
Protein needs are 1.2-1.5 g/kg/day for older patients with illness, which equals 59-74 grams protein/day for a 49kg patient 7, 4
Close monitoring of body weight is mandatory, with intake adjusted accordingly, and indirect calorimetry is the preferred method for measuring energy expenditure if available 7, 4, 9, 2